patchwayraver
Active Member
How To Grow Hydroponic Marijuana
When you grow hydroponic marijuana yourself, you know the crop will be potent (if you started with good seeds) and clean. That is something you can't always count on when buying from someone else. This is especially important if you are growing for medical reasons.
Using hydroponics to grow plants is fairly simple once you understand how it works. Anyone who wants to learn to grow hydroponic marijuana will succeed in time.
When you know how to grow your own, you will not have to pay ridiculous prices for top grade marijuana and you will never run out.
You can use a hydroponic garden to grow just about any kind of plant, not just marijuana. The experience you gain growing hydroponic marijuana can be applied to any other hydroponic crop you decide to grow in the future.
A hydroponic garden will require monitoring to make sure everything is working properly. If you are away from the grow area for long periods of time, growing hydroponic marijuana might not be possible.
How it works: A seed that has been germinated and sprouted a root or a plant cutting (clone) is placed in a hydroponic garden and supplied with nutrients (food) and light. After this, the plant develops a root system and leaves. Plants are given about 16-18 hours of light a day during this (the seedling) stage of growth.
After the plant has put down a solid root system and grown some leaves, it enters the next stage of the marijuana plant life cycle. This is called the growth or vegetative phase. During this phase the light source is on 18 to 24 hours a day. When growing hydroponic marijuana indoors the seedling/vegetative stage usually lasts 4 to 8 weeks.
The next stage is called flowering. When growing indoors, the flowering stage is started by cutting the light down to 12 hours on and 12 hours off per 24 hour period. With most marijuana strains, the flowering stage lasts about 8 to 12 weeks. Almost all THC (the primary cannabinoid that causes marijuana intoxication) is produced during the flowering stage.
Total time from germinating to harvest is about 4 months. This can be shortened to 3 months or less by using two growing areas, one for the first stages of life and another strictly for flowering. At the end of flowering, marijuana plants are harvested then allowed to air dry.
Where To Grow Hydroponic Marijuana
This guide is about growing hydroponic marijuana indoors, so the growing will be done indoors. Where to grow your marijuana depends on what space you have available. An attic, closet or similar space will do, but a room dedicated to growing is preferred.
Things to consider include:
airflow - has to be good
water - easy access to water
well hidden - minimize the chance of theft
electricity - enough power to run everything
temperature - cool area that stays above 60 degrees F
The biggest problem most new growers face is heat. A room with an exhaust fan on the ceiling is a good choice, if it is available. The exhaust fan on the ceiling will help keep the temperature cool, and if needed, you can upgrade to a stronger fan to remove a larger volume of hot air (created by the grow-lights).
A section of a basement also makes a very good area to set up a grow room. An attic will work but heat can be a real problem unless very well ventilated. All grow rooms require fresh air (from another room or outdoors) to replace carbon dioxide that the plants breathe when the grow light(s) are on. Almost any grow room will need some kind of exhaust fan that will move hot air out of the grow room.
After you have decided where you are going to grow, you have to clean the area and keep it clean. That means scrubbing walls, cleaning equipment, washing floors, etc. Carpets should be removed, if possible.
Everything in the growing area should be cleaned then sterilized with something like lysol, bleach, or some other germ killer to prevent the marijuana plants from being harmed by germs, bacteria, molds, etc.
If you are going to grow in an area where the floor may be damaged by water spills (there will be some), the area where the hydroponic system is placed should have some kind of floor covering that will protect it. A thick drop cloth (the plastic sheets painters use to protect items from paint damage) will do a good job.
Once clean, you can paint the walls and ceiling with white paint to reflect light or use black/white visqueen plastic (white side towards the plants so light is reflected). Commercial reflectors like mylar are sometimes used for this purpose because they are more efficient. Do not use mirrors because they absorb light.
gloss white paint is about 70% to 75% reflective
flat white paint is about 75% to 80% reflective
white visqueen plastic is about 70% to 80% reflective
mylar is about 95% reflective
Indica And Sativa
Before you can start to grow, you will need marijuana seeds or clones. There are two species of cannabis that are grown to produce marijuana, they are Cannabis indica and Cannabis sativa. Even though there are dozens, if not hundreds of marijuana strains, most strains used to grow marijuana are mainly indica, mainly sativa, or an indica/sativa mix.
All things considered, mainly indica plants are by far the best plant for hydroponic beginners growing indoors. They are easier to grow, don't get as tall, and produce a larger harvest than sativa plants. The only drawback is indica plants have lower THC levels than sativa plants, this makes them a bit less potent.
As a grower gains experience they may try growing an indica/sativa mix. When very experienced, an indoor hydroponic grower may try a mainly sativa strain. But for the first few crops, stick with indica or indica/sativa plants.
Hydroponic System For Growing Marijuana
Now you have a basic idea of how things work, let's get into more detail. If you are going to be growing hydroponic marijuana and have chosen a suitable location, you will need a hydroponic system, also called a hydroponic garden.
There are different types of hydroponic systems available to marijuana growers. If you would like to know more about hydroponics and the different types of hydroponic systems, there is a good article at wikipedia.
The most common systems for growing marijuana are:
aeroponics
deep water culture
drip (top feed or top irrigation)
ebb and flow
nutrient film technique (NFT)
The method you choose should meet your budget and be able to fit in your growing area. NFT and aeroponic systems are the most efficient types of systems, but they are a bit harder to maintain.
The number of plants your garden can sustain and the area your garden covers will determine how much light you need. Read the section in this guide about lighting before deciding on a hydroponic system.
A hydroponic system is made to grow plants without soil. Plant nutrients are mixed with water and 'delivered' to the plants roots by a pump or other method. This delivering of nutrients means that the plant doesn't have to use as much energy making roots in search of the nutrients it requires.
Energy not used looking for food is used to make the plant develop its leaves and flowers faster than they would if grown in soil.
It's not uncommon for marijuana plants in hydroponic garden to grow as much as 1 to 2 inches or more, per day, during the vegetative growth phase.
Because no soil is used, some hydroponic systems require something for the plants roots to anchor themselves to. This is usually referred to as the growing media or growing medium.
For a personal indoor hydroponic marijuana garden, plants should be grown about eight to sixteen inches apart. Some strains are bushy and they will require more space but produce a larger yield than a slender strain.
Unless you plan on growing small plants, the roots require a fairly large area to grow in. The opening for each plants roots should be about three inches (or larger). This will accommodate a marijuana plant that will produce a half ounce of marijuana or more. Smaller plants can be grown with a smaller space for roots.
The hydroponic garden pictured here is an NFT type garden but other types of hydroponics systems can be found with similar dimensions. It's 24 inches off the floor and covers a 48 inch by 48 inch area.
A reservoir (shown in black in the picture) placed below the area where the plants grow (shown in white in the picture) is filled with water and nutrients. A pump moves this nutrient solution from the reservoir and supplies it to the roots of the plants growing above.
Openings for the plants root system are about 3 inches by 3 inches, ideal for 3 inch rockwool cubes. Capacity is 23 plants spaced about 9 inches apart. Plants grown 9 inches apart will only be able to branch 4.5 inches away from the main stem before competing for light with adjoining plants.
This might be ok for slender plants, but with marijuana plants that will produce 1/2 to 1 ounce each at harvest time, you would only be able to grow a maximum of 9 to 12 plants in a garden with these dimensions. Some of the plant openings wouldn't be occupied. The extra room would allow plants to branch further and produce a larger crop.
If you grew 9 to 12 marijuana plants in a hydroponic garden with these dimensions and used a 400 watt lighting system, the expected yield would be about 1/2 to 1 ounce per plant, every four months.
An indica or indica/sativa strain grown in a properly maintained hydroponic garden like this (9-12 plants supplied with 400 watts of light) would provide enough marijuana to allow you to consume about 2 ounces a month without ever having to buy marijuana again.
A mainly sativa strain might only produce enough marijuana to allow you to consume a bit over 1 ounce of marijuana per month. That is to say, when grown under the same conditions, some sativa plants will only yield 1/2 ounce per plant while an indica or indica/sativa plant could yield nearly 1 ounce per plant.
Lighting For Growing Hydroponic Marijuana
Choosing a hydroponic system will necessitate the consideration of the right grow light for your needs. Metal Halide (mh) and/or High Pressure Sodium (hps) are the lighting systems you need to flower hydroponic marijuana.
Fluorescent and LED grow lights are good for the seedling/vegetative stages of growth (or as supplemental light when flowering) but at the present time, they will not produce as big of a harvest as mh or hps grow lights during flowering. It will also take more time for the plant to mature.
Beware of claims by fluorescent and LED grow light sellers that say their lights will preform as good as mh or hps lights. The only light I have seen that looked like it might compete with a 400 watt mh or hps light was an LED light system that costed over $1000. A good 400 watt mh or hps grow light can be purchased for under $400.
If LED technology improves and prices come down, LED grow lights might become the best choice of grow light in the future. But if you are serious about growing marijuana now, mh or hps are the only grow lights to consider, at least for flowering.
The sun emits light energy that spans from the red to the blue end of the light spectrum. As far as marijuana plants are concerned, in spring-summer when plants start to grow (seedling and vegetative stages) there is more blue spectrum energy, that (along with long days) promotes plant growth.
In summer-fall when plants produce flowers, there is more red spectrum energy. The change in light (and more importantly shorter days) cause hormones in plants to increase flower and THC production.
Metal halide light fixtures produce large amounts of blue spectrum energy and are best for vegetative (beginning) growth. The light produced looks similar to the 'cool white' fluorescent light found in schools, offices, stores, and other high traffic areas.
High pressure sodium light fixtures produce large amounts of red spectrum energy and are best for flowering (later) growth. The light produced looks similar to the 'warm' incandescent lights found in homes, but has a deeper orange-red color. The street lamps in many cities are hps lights.
What light should you get?
In a perfect world both metal halide (mh) and high pressure sodium (hps) would be used during both the vegetative and flowering stages of growth.
For example, a garden with 15 plants or less could use a 250 watt hps and a 250 watt mh lighting fixture. A garden with 20 plants or less could use a 400 watt hps and a 250 watt mh lighting fixture (or 250 watt hps and a 400 watt mh).
This is not always possible because the cost of two light fixtures will be more that of a single fixture. Two lights will also take up more space and might produce more heat than a single unit.
You can run
You can't use a standard high pressure sodium bulb in a metal halide fixture, but you can use a metal halide bulb in a high pressure sodium fixture of the same wattage.
There are special hps bulbs that can be used in a mh fixture and vice-versa. But these conversion bulbs cost about double the price of a standard bulb.
When I began to grow, there was only a 400 watt high pressure sodium fixture available to grow with. A 400 watt metal halide bulb was used in that 400 watt high pressure sodium fixture during the vegetative stage. The light was on 18 to 24 hours a day at this time.
When the plants were ready to start flowering, the 400 watt metal halide bulb was replaced with a 400 watt high pressure sodium bulb. During the flowering phase the high pressure sodium light cycle was changed to 12 hours on and 12 hours off a day. Running a mh bulb in an hps fixture is not recommended operating procedure, but it does work if the need should arise.
If you can only afford a single fixture, get a high pressure sodium fixture with a high pressure sodium bulb and a metal halide bulb (both bulbs rated for the same wattage as your light fixture). Use the metal halide bulb for vegetative growth and the high pressure sodium for flowering. When you have enough money, get a proper metal halide fixture.
The list below gives an approximate idea of the area covered and how many marijuana plants can be grown with a certain wattage light system in a dark room. Any sunlight you can give the plants will increase the number of plants you can grow, and will help the plants grow faster.
The number of plants in the list below is an approximate maximum number you can grow with various wattage mh or hps grow light systems. It is not exact, but it should give you an idea of the area a grow light can cover, and the number of marijuana plants that can be grown in that area.
A 600 watt light system should be started 4 to 5 feet above the tops of the plants, a 1000 watt light system should be started 5 to 6 feet above the tops of the plants.
The light should be lowered a few inches everyday until the light is as close as it can be without harming the plant. You will have to figure out the optimal distance yourself because it will vary depending on bulb efficiency, quality of reflector, and other things.
Whatever your light source, replace bulbs after 6 to 12 months of use. If the light is on 24 hours a day replace it after 6 months. If the light is on 18 hours a day replace it after 9 months. If the light is on 12 hours a day replace it after 12 months.
One note about replacement bulbs, they can be divided into three categories: vertical, horizontal, universal. Vertical bulbs have to be used with fixtures in the vertical position. Horizontal bulbs have to be used with fixtures in the horizontal position. Universal bulbs can be used in a horizontal or vertical position. If you aren't sure what to buy, make sure you get a universal bulb. It will work in either type of fixture.
The standard ceiling is 8 feet (96 inches) from the floor, most hydroponic systems are on a platform that is 18 to 30 inches off the floor and the plant itself will probably be 18 to 36 inches tall when fully grown.
In most cases if your ceiling isn't more than 8 feet (96 inches) from the floor, the largest light system you should get is 400-600 watts. 400-600 watt systems are used by a majority of marijuana growers who are growing for personal consumption. If you need more light, get 250, 400, or 600 watt lights rather than 1000 watt lights.
Experienced growers know how to limit the height of a plant by making plants grow horizontally as opposed to the natural vertical growth marijuana plants follow. The first time grower should use a 1000 watt light systems only in areas with ceiling heights of 10 feet (120 inches) or more.
Seeds Or Clones To Grow Hydroponic Marijuana
Now that you understand hydroponic systems and grow lights, it's time to decide on seeds or clones. Most people start from seeds but someone who is currently growing a crop will be able to provide you with clones from female plants.
Clones are simply cuttings taken from a growing plant. After a cutting is taken from the mother plant, it will develop into an adult plant, if provided with reasonable growing conditions. Clones will be exact copies of the plant they are taken from.
Make sure to get seeds or clones from someone who can tell you the origin of the strain (indica or sativa), expected yield size, expected flowering time, and if the seed is meant to be grown indoors or outdoors.
Marijuana seeds can be hard to obtain. In the past In the past I have ordered from dutch (Holland) seedbanks. Unfortunately some people (like myself and other growers) are paying for seeds and not getting them.
Instead of ordering from Holland (the netherlands, amsterdam, etcetera), it is safest to buy marijuana seeds through a seedbank that ships from Canada, especially if you are ordering from the United States or Canada. In Europe, try ordering from the UK. Make sure to get an outdoor strain if you plan growing outside, or an indoor strain if you want to grow inside.
A mainly indica strain is probably the best choice for an indoor gardener to start with (growing with either hydroponics or soil). They easy to grow indoors, produce a large yield, don't grow tall, and the high is good.
After you grow hydroponic marijuana from seed, you should learn to clone your plants. Once you know how to clone marijuana, you will not have to buy seeds to start a new crop again.
To ensure a supply of seeds for future propagation, you can produce your own by selectively pollinating a single flower on a female plant (not the entire plant) with pollen from a male plant. When the plant is harvested, the single flower that was pollinated will contain hundreds of seeds.
Set up your hydroponic garden and check your light before you germinate the seeds or get clones. Add plain water with no nutrient solution and start your hydroponic system. Make sure everything works and there are no leaks.
Let it run for a day or more before putting the plants in. Tap water must be aged for 3 days or longer prior to being used in a hydroponic garden. So if you added water right from the tap, wait for 3 days before putting the plants in.
When you are sure that your garden functions properly, you will need to germinate your seeds. If you germinated the seed directly onto your growing medium, you can put it in the garden when you know the seed has sprouted a root that is about a quarter of an inch long.
If you germinated the seed on paper towel, wait till after the seeds have germinated and the root is about a quarter of an inch long. When you see that it is, place the seed (root down) in the hydroponic system growing medium according to the manufacturers instructions.
Wash your hands prior to touching the seeds for any reason, and be very gentle. Do not touch the root itself, it is very sensitive and may be permanently damaged if mis-handled. You don't have to, but some growers find tweezers the best way to work with seeds.
If you have obtained clones, set up your hydroponic garden. When you are sure it functions properly, put the clones in the hydroponic system according to the manufacturers instructions.
After the seeds or clones are put into the garden, allow them to remain in darkness for 8 to 10 hours before turning on the light. This is to allow for recovery from the shock of transplanting, this is more important for clones than seeds.
You can start the seedlings or clones off with hps or mh light from the start. But a better idea is to begin with fluorescent light turned on for 16-18 hours a day until you are ready to grow under hps or mh.
The reason for starting off with fluorescent lighting is to not give the plants too much light. Let them build up to it as they would in nature where the seedlings would take root in spring when the sun is not as strong as it is during summer. It also saves energy.
Use a standard double light 48 inch fluorescent fixtures with two 'cool' 30-60 watt bulbs. A 48 inch fixture with bulbs will cost under $50 at most hardware stores. Place the fluorescent fixtures about 3 to 10 inches above the plants.
4 to 6 inches is good, but you might have to raise the light a bit higher so all the plants get some light. Depending on the size of your setup you might need two fixtures, but in most cases one will be enough.
When the plants have a solid root system, they will start to produce leaves. After a minimum of two or three sets of leaves have appeared (usually in 1 to 2 weeks) the plants are ready to really start growing.
Growing Hydroponic Marijuana
Now the plants are ready to start growing (vegetative phase of life). The hydroponic system is working and the plants have two or more sets of leaves. Remove the fluorescent lighting then install and adjust the height of your metal halide or high pressure sodium fixture.
When you first start the metal halide or high pressure sodium light the distance from the top of the plants to the light source should be started at the following height and lowered daily until you find an optimal distance:
You want the plants to be as close to the light as possible without being burned. If the parts of the plants closest to the light dry out, raise the height of the light source, they are too close. If the plants are too far from the light they will stretch and be tall but not have much bud. That is a waste of space and light energy.
Start high and lower the light a few inches daily until you think the height is right and. Don't forget to raise the light as the plants grow. Plants can grow 3 inches in a single day.
As the plant grows, some leaves will die and should be removed from the plant by cutting them rather than pulling them off by hand. You may also want to prune your plant, see why and how to prune and pruning tips for an explanation.
The plant is allowed to grow in the vegetative stage until it is big enough to provide a worthwhile amount of marijuana when harvested. When growing hydroponic marijuana indoors, the seedling/vegetative stage usually lasts 4 to 8 weeks.
You can let the vegetative stage last several months with no negative effects on the plant. But the vegetative phase can be ended (and the flowering stage began) as soon as the plants are large enough.
Hydroponic Marijuana Flowering
Flowering is the phase of marijuana growth that produces the most THC (the primary chemical that produces intoxication). You could start flowering when the plants are a minimum of about six inches high and have at least four sets of leaves, but the amount of marijuana produced by a plant of this size would be small.
Starting the flowering process when the plants are about twelve inches tall is recommended when using a 400 watt light source (usually after 4 to 8 weeks of vegetative growth). Any taller and the bud isn't as potent because the light can't reach some of the lower branches, any shorter and the harvest is too small.
If you are using a 250 watt light try flowering when the plants are about eight inches tall. Marijuana plants grown under 600-1000 watt systems can be eighteen inches or taller before flowering. Higher wattage bulbs produce enough light to penetrate to the lower branches. The higher the wattage, the taller (more buds) your plants can be without loosing potency.
When the plant is large enough to force into flowering, turn off the light and allow the plant to remain in complete darkness for 24 to 36 hours (you don't have to do this but I've found the plants flower faster by doing so).
To initiate flowering, adjust the light timer to turn the light on for 10-14 hours a day. Most people start a light cycle of 12 hours a day on 12 hours a day off. If the plant got 20-24 hours of light per day prior to flowering, it will flower when the light is on for between 10-14 hours a day.
Less than 12 hours light a day and the plants will be ready to harvest sooner but they will produce a smaller yield. More than 12 hours of light a day and the plants will produce a lager yield but it will take longer for them to mature and harvest.
When you grow hydroponic marijuana indoors the height of the plant will continue to increase for about two to four weeks after flowering has been started.
After two to four weeks of flowering, the height of the plant will stop increasing and most of the female plants energy will be used for flower production, unless pollinated when some energy will be used to produce seeds.
During flowering, the dark period must be perfectly dark. No room light, sun light, or any other light should reach the plant in the 12 hours of darkness that the plant must get everyday.
The strongest light that should reach the plant during the dark period of flowering would equal that of moonlight and only for short periods. Stronger light than this will delay flowering, and if it continues there is a chance that the plant will not flower, but stay in the vegetative phase.
This is more important in the fist 4 weeks of flowering. When the plants have started to flower for over a month, small amounts of light for short periods of time during the dark period are not as harmful.
You will know the plants are flowering when you see what look like little sacks appearing on the male plants and white hairs (pistils) developing at bud sites of female plants. They should be visible after about two weeks of the flowering light cycle.
The white hairs turn color as the plant ages. They will eventually be the red/brown hairs that you see on marijuana that you have probably smoked in the past or are smoking now.
When you grow hydroponic marijuana yourself, you know the crop will be potent (if you started with good seeds) and clean. That is something you can't always count on when buying from someone else. This is especially important if you are growing for medical reasons.
Using hydroponics to grow plants is fairly simple once you understand how it works. Anyone who wants to learn to grow hydroponic marijuana will succeed in time.
When you know how to grow your own, you will not have to pay ridiculous prices for top grade marijuana and you will never run out.
You can use a hydroponic garden to grow just about any kind of plant, not just marijuana. The experience you gain growing hydroponic marijuana can be applied to any other hydroponic crop you decide to grow in the future.
A hydroponic garden will require monitoring to make sure everything is working properly. If you are away from the grow area for long periods of time, growing hydroponic marijuana might not be possible.
How it works: A seed that has been germinated and sprouted a root or a plant cutting (clone) is placed in a hydroponic garden and supplied with nutrients (food) and light. After this, the plant develops a root system and leaves. Plants are given about 16-18 hours of light a day during this (the seedling) stage of growth.
After the plant has put down a solid root system and grown some leaves, it enters the next stage of the marijuana plant life cycle. This is called the growth or vegetative phase. During this phase the light source is on 18 to 24 hours a day. When growing hydroponic marijuana indoors the seedling/vegetative stage usually lasts 4 to 8 weeks.
The next stage is called flowering. When growing indoors, the flowering stage is started by cutting the light down to 12 hours on and 12 hours off per 24 hour period. With most marijuana strains, the flowering stage lasts about 8 to 12 weeks. Almost all THC (the primary cannabinoid that causes marijuana intoxication) is produced during the flowering stage.
Total time from germinating to harvest is about 4 months. This can be shortened to 3 months or less by using two growing areas, one for the first stages of life and another strictly for flowering. At the end of flowering, marijuana plants are harvested then allowed to air dry.
Where To Grow Hydroponic Marijuana
This guide is about growing hydroponic marijuana indoors, so the growing will be done indoors. Where to grow your marijuana depends on what space you have available. An attic, closet or similar space will do, but a room dedicated to growing is preferred.
Things to consider include:
airflow - has to be good
water - easy access to water
well hidden - minimize the chance of theft
electricity - enough power to run everything
temperature - cool area that stays above 60 degrees F
The biggest problem most new growers face is heat. A room with an exhaust fan on the ceiling is a good choice, if it is available. The exhaust fan on the ceiling will help keep the temperature cool, and if needed, you can upgrade to a stronger fan to remove a larger volume of hot air (created by the grow-lights).
A section of a basement also makes a very good area to set up a grow room. An attic will work but heat can be a real problem unless very well ventilated. All grow rooms require fresh air (from another room or outdoors) to replace carbon dioxide that the plants breathe when the grow light(s) are on. Almost any grow room will need some kind of exhaust fan that will move hot air out of the grow room.
After you have decided where you are going to grow, you have to clean the area and keep it clean. That means scrubbing walls, cleaning equipment, washing floors, etc. Carpets should be removed, if possible.
Everything in the growing area should be cleaned then sterilized with something like lysol, bleach, or some other germ killer to prevent the marijuana plants from being harmed by germs, bacteria, molds, etc.
If you are going to grow in an area where the floor may be damaged by water spills (there will be some), the area where the hydroponic system is placed should have some kind of floor covering that will protect it. A thick drop cloth (the plastic sheets painters use to protect items from paint damage) will do a good job.
Once clean, you can paint the walls and ceiling with white paint to reflect light or use black/white visqueen plastic (white side towards the plants so light is reflected). Commercial reflectors like mylar are sometimes used for this purpose because they are more efficient. Do not use mirrors because they absorb light.
gloss white paint is about 70% to 75% reflective
flat white paint is about 75% to 80% reflective
white visqueen plastic is about 70% to 80% reflective
mylar is about 95% reflective
Indica And Sativa
Before you can start to grow, you will need marijuana seeds or clones. There are two species of cannabis that are grown to produce marijuana, they are Cannabis indica and Cannabis sativa. Even though there are dozens, if not hundreds of marijuana strains, most strains used to grow marijuana are mainly indica, mainly sativa, or an indica/sativa mix.
All things considered, mainly indica plants are by far the best plant for hydroponic beginners growing indoors. They are easier to grow, don't get as tall, and produce a larger harvest than sativa plants. The only drawback is indica plants have lower THC levels than sativa plants, this makes them a bit less potent.
As a grower gains experience they may try growing an indica/sativa mix. When very experienced, an indoor hydroponic grower may try a mainly sativa strain. But for the first few crops, stick with indica or indica/sativa plants.
Hydroponic System For Growing Marijuana
Now you have a basic idea of how things work, let's get into more detail. If you are going to be growing hydroponic marijuana and have chosen a suitable location, you will need a hydroponic system, also called a hydroponic garden.
There are different types of hydroponic systems available to marijuana growers. If you would like to know more about hydroponics and the different types of hydroponic systems, there is a good article at wikipedia.
The most common systems for growing marijuana are:
aeroponics
deep water culture
drip (top feed or top irrigation)
ebb and flow
nutrient film technique (NFT)
The method you choose should meet your budget and be able to fit in your growing area. NFT and aeroponic systems are the most efficient types of systems, but they are a bit harder to maintain.
The number of plants your garden can sustain and the area your garden covers will determine how much light you need. Read the section in this guide about lighting before deciding on a hydroponic system.
A hydroponic system is made to grow plants without soil. Plant nutrients are mixed with water and 'delivered' to the plants roots by a pump or other method. This delivering of nutrients means that the plant doesn't have to use as much energy making roots in search of the nutrients it requires.
Energy not used looking for food is used to make the plant develop its leaves and flowers faster than they would if grown in soil.
It's not uncommon for marijuana plants in hydroponic garden to grow as much as 1 to 2 inches or more, per day, during the vegetative growth phase.
Because no soil is used, some hydroponic systems require something for the plants roots to anchor themselves to. This is usually referred to as the growing media or growing medium.
For a personal indoor hydroponic marijuana garden, plants should be grown about eight to sixteen inches apart. Some strains are bushy and they will require more space but produce a larger yield than a slender strain.
Unless you plan on growing small plants, the roots require a fairly large area to grow in. The opening for each plants roots should be about three inches (or larger). This will accommodate a marijuana plant that will produce a half ounce of marijuana or more. Smaller plants can be grown with a smaller space for roots.
The hydroponic garden pictured here is an NFT type garden but other types of hydroponics systems can be found with similar dimensions. It's 24 inches off the floor and covers a 48 inch by 48 inch area.
A reservoir (shown in black in the picture) placed below the area where the plants grow (shown in white in the picture) is filled with water and nutrients. A pump moves this nutrient solution from the reservoir and supplies it to the roots of the plants growing above.
Openings for the plants root system are about 3 inches by 3 inches, ideal for 3 inch rockwool cubes. Capacity is 23 plants spaced about 9 inches apart. Plants grown 9 inches apart will only be able to branch 4.5 inches away from the main stem before competing for light with adjoining plants.
This might be ok for slender plants, but with marijuana plants that will produce 1/2 to 1 ounce each at harvest time, you would only be able to grow a maximum of 9 to 12 plants in a garden with these dimensions. Some of the plant openings wouldn't be occupied. The extra room would allow plants to branch further and produce a larger crop.
If you grew 9 to 12 marijuana plants in a hydroponic garden with these dimensions and used a 400 watt lighting system, the expected yield would be about 1/2 to 1 ounce per plant, every four months.
An indica or indica/sativa strain grown in a properly maintained hydroponic garden like this (9-12 plants supplied with 400 watts of light) would provide enough marijuana to allow you to consume about 2 ounces a month without ever having to buy marijuana again.
A mainly sativa strain might only produce enough marijuana to allow you to consume a bit over 1 ounce of marijuana per month. That is to say, when grown under the same conditions, some sativa plants will only yield 1/2 ounce per plant while an indica or indica/sativa plant could yield nearly 1 ounce per plant.
Lighting For Growing Hydroponic Marijuana
Choosing a hydroponic system will necessitate the consideration of the right grow light for your needs. Metal Halide (mh) and/or High Pressure Sodium (hps) are the lighting systems you need to flower hydroponic marijuana.
Fluorescent and LED grow lights are good for the seedling/vegetative stages of growth (or as supplemental light when flowering) but at the present time, they will not produce as big of a harvest as mh or hps grow lights during flowering. It will also take more time for the plant to mature.
Beware of claims by fluorescent and LED grow light sellers that say their lights will preform as good as mh or hps lights. The only light I have seen that looked like it might compete with a 400 watt mh or hps light was an LED light system that costed over $1000. A good 400 watt mh or hps grow light can be purchased for under $400.
If LED technology improves and prices come down, LED grow lights might become the best choice of grow light in the future. But if you are serious about growing marijuana now, mh or hps are the only grow lights to consider, at least for flowering.
The sun emits light energy that spans from the red to the blue end of the light spectrum. As far as marijuana plants are concerned, in spring-summer when plants start to grow (seedling and vegetative stages) there is more blue spectrum energy, that (along with long days) promotes plant growth.
In summer-fall when plants produce flowers, there is more red spectrum energy. The change in light (and more importantly shorter days) cause hormones in plants to increase flower and THC production.
Metal halide light fixtures produce large amounts of blue spectrum energy and are best for vegetative (beginning) growth. The light produced looks similar to the 'cool white' fluorescent light found in schools, offices, stores, and other high traffic areas.
High pressure sodium light fixtures produce large amounts of red spectrum energy and are best for flowering (later) growth. The light produced looks similar to the 'warm' incandescent lights found in homes, but has a deeper orange-red color. The street lamps in many cities are hps lights.
What light should you get?
In a perfect world both metal halide (mh) and high pressure sodium (hps) would be used during both the vegetative and flowering stages of growth.
For example, a garden with 15 plants or less could use a 250 watt hps and a 250 watt mh lighting fixture. A garden with 20 plants or less could use a 400 watt hps and a 250 watt mh lighting fixture (or 250 watt hps and a 400 watt mh).
This is not always possible because the cost of two light fixtures will be more that of a single fixture. Two lights will also take up more space and might produce more heat than a single unit.
You can run
- hps light through both stages of growth (ok).
- mh light through both stages of growth (ok).
- run a mh light through the veg phase of growth followed by hps light through flowering (very good).
- run both mh and hps light through both stages of growth (best).
You can't use a standard high pressure sodium bulb in a metal halide fixture, but you can use a metal halide bulb in a high pressure sodium fixture of the same wattage.
There are special hps bulbs that can be used in a mh fixture and vice-versa. But these conversion bulbs cost about double the price of a standard bulb.
When I began to grow, there was only a 400 watt high pressure sodium fixture available to grow with. A 400 watt metal halide bulb was used in that 400 watt high pressure sodium fixture during the vegetative stage. The light was on 18 to 24 hours a day at this time.
When the plants were ready to start flowering, the 400 watt metal halide bulb was replaced with a 400 watt high pressure sodium bulb. During the flowering phase the high pressure sodium light cycle was changed to 12 hours on and 12 hours off a day. Running a mh bulb in an hps fixture is not recommended operating procedure, but it does work if the need should arise.
If you can only afford a single fixture, get a high pressure sodium fixture with a high pressure sodium bulb and a metal halide bulb (both bulbs rated for the same wattage as your light fixture). Use the metal halide bulb for vegetative growth and the high pressure sodium for flowering. When you have enough money, get a proper metal halide fixture.
The list below gives an approximate idea of the area covered and how many marijuana plants can be grown with a certain wattage light system in a dark room. Any sunlight you can give the plants will increase the number of plants you can grow, and will help the plants grow faster.
The number of plants in the list below is an approximate maximum number you can grow with various wattage mh or hps grow light systems. It is not exact, but it should give you an idea of the area a grow light can cover, and the number of marijuana plants that can be grown in that area.
- A 250 watt fixture will supply enough light to cover a 2.5 foot by 2.5 foot grow area. (6 plants or less)
- A 400 watt fixture will supply enough light to cover a 4 foot by 4 foot grow area. (12 plants or less)
- A 600 watt fixture will supply enough light to cover a 5 foot by 5 foot grow area. (18 plants or less)
- A 1000 watt fixture will supply enough light to cover a 6.5 foot by 6.5 foot grow area. (30 plants or less)
A 600 watt light system should be started 4 to 5 feet above the tops of the plants, a 1000 watt light system should be started 5 to 6 feet above the tops of the plants.
The light should be lowered a few inches everyday until the light is as close as it can be without harming the plant. You will have to figure out the optimal distance yourself because it will vary depending on bulb efficiency, quality of reflector, and other things.
Whatever your light source, replace bulbs after 6 to 12 months of use. If the light is on 24 hours a day replace it after 6 months. If the light is on 18 hours a day replace it after 9 months. If the light is on 12 hours a day replace it after 12 months.
One note about replacement bulbs, they can be divided into three categories: vertical, horizontal, universal. Vertical bulbs have to be used with fixtures in the vertical position. Horizontal bulbs have to be used with fixtures in the horizontal position. Universal bulbs can be used in a horizontal or vertical position. If you aren't sure what to buy, make sure you get a universal bulb. It will work in either type of fixture.
The standard ceiling is 8 feet (96 inches) from the floor, most hydroponic systems are on a platform that is 18 to 30 inches off the floor and the plant itself will probably be 18 to 36 inches tall when fully grown.
In most cases if your ceiling isn't more than 8 feet (96 inches) from the floor, the largest light system you should get is 400-600 watts. 400-600 watt systems are used by a majority of marijuana growers who are growing for personal consumption. If you need more light, get 250, 400, or 600 watt lights rather than 1000 watt lights.
Experienced growers know how to limit the height of a plant by making plants grow horizontally as opposed to the natural vertical growth marijuana plants follow. The first time grower should use a 1000 watt light systems only in areas with ceiling heights of 10 feet (120 inches) or more.
Seeds Or Clones To Grow Hydroponic Marijuana
Now that you understand hydroponic systems and grow lights, it's time to decide on seeds or clones. Most people start from seeds but someone who is currently growing a crop will be able to provide you with clones from female plants.
Clones are simply cuttings taken from a growing plant. After a cutting is taken from the mother plant, it will develop into an adult plant, if provided with reasonable growing conditions. Clones will be exact copies of the plant they are taken from.
Make sure to get seeds or clones from someone who can tell you the origin of the strain (indica or sativa), expected yield size, expected flowering time, and if the seed is meant to be grown indoors or outdoors.
Marijuana seeds can be hard to obtain. In the past In the past I have ordered from dutch (Holland) seedbanks. Unfortunately some people (like myself and other growers) are paying for seeds and not getting them.
Instead of ordering from Holland (the netherlands, amsterdam, etcetera), it is safest to buy marijuana seeds through a seedbank that ships from Canada, especially if you are ordering from the United States or Canada. In Europe, try ordering from the UK. Make sure to get an outdoor strain if you plan growing outside, or an indoor strain if you want to grow inside.
A mainly indica strain is probably the best choice for an indoor gardener to start with (growing with either hydroponics or soil). They easy to grow indoors, produce a large yield, don't grow tall, and the high is good.
After you grow hydroponic marijuana from seed, you should learn to clone your plants. Once you know how to clone marijuana, you will not have to buy seeds to start a new crop again.
To ensure a supply of seeds for future propagation, you can produce your own by selectively pollinating a single flower on a female plant (not the entire plant) with pollen from a male plant. When the plant is harvested, the single flower that was pollinated will contain hundreds of seeds.
Set up your hydroponic garden and check your light before you germinate the seeds or get clones. Add plain water with no nutrient solution and start your hydroponic system. Make sure everything works and there are no leaks.
Let it run for a day or more before putting the plants in. Tap water must be aged for 3 days or longer prior to being used in a hydroponic garden. So if you added water right from the tap, wait for 3 days before putting the plants in.
When you are sure that your garden functions properly, you will need to germinate your seeds. If you germinated the seed directly onto your growing medium, you can put it in the garden when you know the seed has sprouted a root that is about a quarter of an inch long.
If you germinated the seed on paper towel, wait till after the seeds have germinated and the root is about a quarter of an inch long. When you see that it is, place the seed (root down) in the hydroponic system growing medium according to the manufacturers instructions.
Wash your hands prior to touching the seeds for any reason, and be very gentle. Do not touch the root itself, it is very sensitive and may be permanently damaged if mis-handled. You don't have to, but some growers find tweezers the best way to work with seeds.
If you have obtained clones, set up your hydroponic garden. When you are sure it functions properly, put the clones in the hydroponic system according to the manufacturers instructions.
After the seeds or clones are put into the garden, allow them to remain in darkness for 8 to 10 hours before turning on the light. This is to allow for recovery from the shock of transplanting, this is more important for clones than seeds.
You can start the seedlings or clones off with hps or mh light from the start. But a better idea is to begin with fluorescent light turned on for 16-18 hours a day until you are ready to grow under hps or mh.
The reason for starting off with fluorescent lighting is to not give the plants too much light. Let them build up to it as they would in nature where the seedlings would take root in spring when the sun is not as strong as it is during summer. It also saves energy.
Use a standard double light 48 inch fluorescent fixtures with two 'cool' 30-60 watt bulbs. A 48 inch fixture with bulbs will cost under $50 at most hardware stores. Place the fluorescent fixtures about 3 to 10 inches above the plants.
4 to 6 inches is good, but you might have to raise the light a bit higher so all the plants get some light. Depending on the size of your setup you might need two fixtures, but in most cases one will be enough.
When the plants have a solid root system, they will start to produce leaves. After a minimum of two or three sets of leaves have appeared (usually in 1 to 2 weeks) the plants are ready to really start growing.
Growing Hydroponic Marijuana
Now the plants are ready to start growing (vegetative phase of life). The hydroponic system is working and the plants have two or more sets of leaves. Remove the fluorescent lighting then install and adjust the height of your metal halide or high pressure sodium fixture.
When you first start the metal halide or high pressure sodium light the distance from the top of the plants to the light source should be started at the following height and lowered daily until you find an optimal distance:
- 18 to 30 inches for 250 watt light
- 3 to 4 feet for 400 watt light
- 4 to 5 feet for 600 watt light
- 5 to 6 feet for 1000 watt light
You want the plants to be as close to the light as possible without being burned. If the parts of the plants closest to the light dry out, raise the height of the light source, they are too close. If the plants are too far from the light they will stretch and be tall but not have much bud. That is a waste of space and light energy.
Start high and lower the light a few inches daily until you think the height is right and. Don't forget to raise the light as the plants grow. Plants can grow 3 inches in a single day.
As the plant grows, some leaves will die and should be removed from the plant by cutting them rather than pulling them off by hand. You may also want to prune your plant, see why and how to prune and pruning tips for an explanation.
The plant is allowed to grow in the vegetative stage until it is big enough to provide a worthwhile amount of marijuana when harvested. When growing hydroponic marijuana indoors, the seedling/vegetative stage usually lasts 4 to 8 weeks.
You can let the vegetative stage last several months with no negative effects on the plant. But the vegetative phase can be ended (and the flowering stage began) as soon as the plants are large enough.
Hydroponic Marijuana Flowering
Flowering is the phase of marijuana growth that produces the most THC (the primary chemical that produces intoxication). You could start flowering when the plants are a minimum of about six inches high and have at least four sets of leaves, but the amount of marijuana produced by a plant of this size would be small.
Starting the flowering process when the plants are about twelve inches tall is recommended when using a 400 watt light source (usually after 4 to 8 weeks of vegetative growth). Any taller and the bud isn't as potent because the light can't reach some of the lower branches, any shorter and the harvest is too small.
If you are using a 250 watt light try flowering when the plants are about eight inches tall. Marijuana plants grown under 600-1000 watt systems can be eighteen inches or taller before flowering. Higher wattage bulbs produce enough light to penetrate to the lower branches. The higher the wattage, the taller (more buds) your plants can be without loosing potency.
When the plant is large enough to force into flowering, turn off the light and allow the plant to remain in complete darkness for 24 to 36 hours (you don't have to do this but I've found the plants flower faster by doing so).
To initiate flowering, adjust the light timer to turn the light on for 10-14 hours a day. Most people start a light cycle of 12 hours a day on 12 hours a day off. If the plant got 20-24 hours of light per day prior to flowering, it will flower when the light is on for between 10-14 hours a day.
Less than 12 hours light a day and the plants will be ready to harvest sooner but they will produce a smaller yield. More than 12 hours of light a day and the plants will produce a lager yield but it will take longer for them to mature and harvest.
When you grow hydroponic marijuana indoors the height of the plant will continue to increase for about two to four weeks after flowering has been started.
After two to four weeks of flowering, the height of the plant will stop increasing and most of the female plants energy will be used for flower production, unless pollinated when some energy will be used to produce seeds.
During flowering, the dark period must be perfectly dark. No room light, sun light, or any other light should reach the plant in the 12 hours of darkness that the plant must get everyday.
The strongest light that should reach the plant during the dark period of flowering would equal that of moonlight and only for short periods. Stronger light than this will delay flowering, and if it continues there is a chance that the plant will not flower, but stay in the vegetative phase.
This is more important in the fist 4 weeks of flowering. When the plants have started to flower for over a month, small amounts of light for short periods of time during the dark period are not as harmful.
You will know the plants are flowering when you see what look like little sacks appearing on the male plants and white hairs (pistils) developing at bud sites of female plants. They should be visible after about two weeks of the flowering light cycle.
The white hairs turn color as the plant ages. They will eventually be the red/brown hairs that you see on marijuana that you have probably smoked in the past or are smoking now.
