DankBudzzz
Well-Known Member
Is a 250 watt hps enough or do I need a 400 watt. I plan on veggin for 1.5 months and then flowering.
HPS for 4-6 plants?
- Thread starter DankBudzzz
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Man o' the green
Active Member
I'd go for a 600W with more than four plants of that size.
High Time 420
Well-Known Member
Go with a 6oow if your going to buy a HID.
That will do a 4x4 area.
That will do a 4x4 area.
cylee89
Well-Known Member
Alright, I think you're missing the concept here.
Plants have a genetic limitation, and will only produce buds to a certain limit, given that you are doing EVERYTHING right.
In general, it is normal to see people yield 0.5g/W of light.
SO, if you are doing things right, you would be yielding 125g for a 250W HPS, and 200g for a 400W HPS (on average), no matter how many plants
You could have a hundred plants in an area under 250w HPS and you would still observe such yields on the long run.
In conclusion, your choice should depend on whether you can control heat issues or not, and how much you want to yield!
Two plants under a 250W HPS could yield a lot! Under a 400W HPS, maybe even more!
Plants have a genetic limitation, and will only produce buds to a certain limit, given that you are doing EVERYTHING right.
In general, it is normal to see people yield 0.5g/W of light.
SO, if you are doing things right, you would be yielding 125g for a 250W HPS, and 200g for a 400W HPS (on average), no matter how many plants
You could have a hundred plants in an area under 250w HPS and you would still observe such yields on the long run.
In conclusion, your choice should depend on whether you can control heat issues or not, and how much you want to yield!
Two plants under a 250W HPS could yield a lot! Under a 400W HPS, maybe even more!
Pipe Dream
Well-Known Member
Well in order to acheive those yeilds "you have to do everything right" and one of the most important variables is efficently using the light. If you grow 1 plant under a 1000 watt light it doesn't mean the plant will yeild 500 grams. It could but that would mean some good LSTing and extra veg time.Alright, I think you're missing the concept here.
Plants have a genetic limitation, and will only produce buds to a certain limit, given that you are doing EVERYTHING right.
In general, it is normal to see people yield 0.5g/W of light.
SO, if you are doing things right, you would be yielding 125g for a 250W HPS, and 200g for a 400W HPS (on average), no matter how many plants
You could have a hundred plants in an area under 250w HPS and you would still observe such yields on the long run.
In conclusion, your choice should depend on whether you can control heat issues or not, and how much you want to yield!
Two plants under a 250W HPS could yield a lot! Under a 400W HPS, maybe even more!
I would say a 600 is definately a great option but you could go as low as a 400 in my opinion. I have grown 6 plants under a 400 wat HPS and had room to spare. Currently I have some plants under a 400 MH and I vegged for 6 weeks. I topped them to keep them short and I could definately squeeze 6 of them underneath it.
Man o' the green
Active Member
HPS is not absolute light available to the plant, it is a point source. Everything that doesn't hit the plant's leaves from the source must be 100% reflected back for the above statement to be true. That is why coverage area is so important. Four plants that veg for a while will get pretty big and need higher intensity light to make up for the reflective losses and shading.SO, if you are doing things right, you would be yielding 125g for a 250W HPS, and 200g for a 400W HPS (on average), no matter how many plants
You could have a hundred plants in an area under 250w HPS and you would still observe such yields on the long run.
In conclusion, your choice should depend on whether you can control heat issues or not, and how much you want to yield!
Two plants under a 250W HPS could yield a lot! Under a 400W HPS, maybe even more!
Of course there is a relationship between product and wattage, but geometry and the inverse-sqare law makes it a little more complicated.
My opinion : Always over-engineer for your current needs. Get a relative maximum yield and deal with whatever heat is generated. If you can't deal with the heat, maybe fewer plants and less wattage is a better idea. The above poster is correct, your limit usually ends up being about heat transfer anyway. 400W is good, but if you can keep a 600W cool, go for it.
Brick Top
New Member
You can squeeze 4 plants into the light footprint of a 250-watt HID light but you said you want to/will veg for 1.5 months. You will outgrow the light penetration of a 250-watt light. Vegging beyond 10 inches max with a 250-watt HID light, especially if something is predominantly sativa, is a waste. The lower part of your plants will literally die out, your tightest branches/nodes will die off from lack of light. Roughly the lower third of the plants that do survive will produce little. The middle third will produce half-decent and the upper third will produce fairly well.
Ask yourself if the additional time to veg that long, using inadequate lighting, is really worth the additional overall growing time when over one third of the plants will hardly produce any bud, none at all at the lowest levels of the plants, and not produce very impressively on another third of the plants?
A 250-watt HID light will only give you roughly 18 inches of adequate light penetration. Below that the plants are in low light conditions.
A 400-watt with a quality reflective hood will do the trick. A 600-watt would be even better but then if you are growing only 4 to 6 plants possibly there is an area limitation and that might mean possible temperature problems needing more cooling capabilities. In other words a 400-watt might be best in your case.
When you chose 1.5 months of vegging how did you come to that decision? Most say plants will double to triple in height while in flower but in my decades of experience triple is more likely than double and I have had some strains increase in height nearly six times what they were when I changed light periods.
Did you figure out just how much actual usable growing height you have to work with or did you just arbitrarily pick 1.5 months for vegging, and even if you figured it do you really know how tall your vegging plants will be at 1/5 months of growth?
For those who never figured actual usable growing height here is what you need to do. Take the overall height of your room or closet etc. For easy math lets say it is 8 exactly. Measure from the floor to the top of your growing medium. Lets say you are growing in pots and to the top of your soil is 1. Subtract 1 from 8 and that leaves you 7. Now measure how much space your light/reflective hood takes up/fills when raised as high as it can go. Lets just say that is 18 inches. Subtract 18 inches from 7 and you now have 5 ½. Then you need to subtract the minimum amount of space you need to maintain from your light to your plant tops. Again lets just say that is 1. Subtract 1 from 5 ½ and you are now down to 4 ½. That means 4 ½ feet would be your maximum usable growing height out of the entire 8 you began with and that seemed like a lot of height to work with.
Keep in mind each time you go up in wattage you need more distance between the tops of your plants and your light, shortening/lowering your overall usable growing height UNLESS you pick a CoolTube or some other type of glass enclosed vented light hood. Without picking such a light you add intense bulb heat and that takes away usable growing height.
Brick Top
New Member
Lol I'm planning to grow 6 clones in 16oz party cups under the 250W HPS. Let's see how it goes.
I can tell you how it will go. Root-bound.
Brick Top
New Member
Being part owner in a family owned nursery I have a slight bit of knowledge and experience with genetic limitations of plants but do you not believe that to a degree they can be manipulated?
A recent grow was four Nevilles Haze and four Lemon Skunk. I topped half of them, two of each strain, following Uncle Bens topping technique. Three topped plants developed for main leaders and the other plant developed three main leaders.
Each topped plant had many more budsites on it than on the plants that were not topped. About the only buds that could be compared closely would be the colas and while the colas on the topped plants were not individually as large as on the plants that were not topped, combined they produced more per topped plant than plant that was not topped.
How does that fit your genetic limitations to only produce buds to a certain limit statement?
It is just a matter of stimulating/manipulating or call it tricking, plant hormones to increase production.
Try growing tall bushes under a, or several, 250-watt HID lights, like it appears the thread starter is thinking of attempting by vegging for a month and a half and then try another grow with the same lighting and top your plants and continually tie them down or use a SCROG system and see how your grams per watts used changes. It will change.
Two plants under a 250-watt light, unless grown using a system to keep them low, will not be capable of growing much bud. The plants will outgrow the amount of usable light they receive and any part of the plants below that level of light will not produce and the area just above it will hardly produce. Only the upper portions of the plants will produce well, and that will not match the growth of a higher wattage HID light.
Growing bushes/Christmas trees with low wattage HID lighting is a waste of time. All you do is add to your overall growing time by adding time for vegging that will not result in increased production, or at the very least not an appreciable amount of increased production.
I find it amusing that many people will not grow a sativa or something predominantly sativa because of the longer flowering period but then they will grow something more indica and do it under a low wattage light setup and veg for weeks longer than they should resulting in little to nothing to show for the additional time. They add weeks to the overall timeframe of their grow. Just talking time they would be roughly as well off growing a sativa and starting it at 12/12 or only vegging for about a week and then go to flower. It would cut out weeks of vegging an indica that would bring them little to nothing in return for their time and efforts and expense, and of course the risk involved that is faced every day a grow is underway.
For the number of plants being talked about a 400-watt light is totally adequate. A 600-watt would be better, IF heat issues would not then become a problem, but the footprint and light penetration of a 400-watt HID light would be enough for 4 to 6 plants, and it would be VASTLY better than a 250-watt HID, or multiple 250-watt HIDs.
shannonball
Well-Known Member
brick top is correct in his opinion. I think a 400 will do you great based on what you stated. Heat is the biggest worry you might have with a 600, even a 400 will produce heat, so plan for heat and if it doesn't happen then nothing lost. Think about where you are going to have your grow and with the summer coming on take that into consideration. We bought a 250 as we only grow two plants at a time...which is all we need late winter/late fall grows. In retrospect we wish we'd had purchased a 400 instead of the 250, but doing only two plants and two grows a year is plenty good for us. We've done well with our largest cured weight of 9.4 oz between the two plants. Our average is probably around 5-6 oz. per grow. We use LST in a 3x3 DR80 grow tent.
DankBudzzz
Well-Known Member
600 Watts or higher isn't an option for my closet. I think 400 would be perfect even with 5 plants. I also have 6 cfls and some T8s that I'm using for veg thus far so I think it will be ample enough provided I can control heat.
cylee89
Well-Known Member
DankBudzzz
Well-Known Member
Check out my first grow at two weeks. One is way bigger then the other 4.
https://www.rollitup.org/general-marijuana-growing/322165-first-grow-two-weeks.html
https://www.rollitup.org/general-marijuana-growing/322165-first-grow-two-weeks.html
sonar
Well-Known Member
So you are basically saying a 250 watt light is pretty much useless unless you do something like LST...
Touchet
New Member
I am going to stay out of the above discussion and address only a single part of it, genetic limitations. Think of your plants like yourself, how much of your brain do you use in comparison with how much you actually have? Plants are very similar, they only use a small percentage of the photosynthesis power they actually have because of genetic limitations. It's a fact. However it's history now. Without trying to sound like a rep for them, Dutch Master Gold line Liquid Light when used with penetrator takes over where mother nature left off. A big part of a plants light-processing ability lays in the amount of selected carbohydrates it has on hand to assist in maximizing its natural genetic photosynthetic power during the Calvin cycle.
I have been using their products at the recommendation of fellow long time family growers. This stuff is phenomenal, my plants are freaks and I love them. And I'm using (2) 150 watt HPS for flowering a 3ft deep 5 ft wide 4ft tall chamber. I have pics of clones that got the treatment and pics of clones that didn't going up tomorrow so people can see the change for themselves. There are currently pics in my journal of plants at the exact time frame you requested. Before I put mine into flowering cycle I remove the bottom 10-15 sets of branches off of each plant for clones. This leaves me with about 10-15 sets of branches on the top half to form the canopy.
Hope any of this helps you.
I have been using their products at the recommendation of fellow long time family growers. This stuff is phenomenal, my plants are freaks and I love them. And I'm using (2) 150 watt HPS for flowering a 3ft deep 5 ft wide 4ft tall chamber. I have pics of clones that got the treatment and pics of clones that didn't going up tomorrow so people can see the change for themselves. There are currently pics in my journal of plants at the exact time frame you requested. Before I put mine into flowering cycle I remove the bottom 10-15 sets of branches off of each plant for clones. This leaves me with about 10-15 sets of branches on the top half to form the canopy.
Hope any of this helps you.
sonar
Well-Known Member
Well I know this is an older thread, but about a month ago a bought a 250w hps off a friend of mine thinking it was going to be the shit. It was brand new in the box, but he needed money so he sold it to me for like $40. I have't had a chance to use it yet, since it was putting off too much heat for my setup. The point being, when I do get a chance to use it, is it doing to be useless? I mean, I never topped plants before, but I'm assuming that would be a method brick top was talking about. If he says so I'll believe him, but I plugged this thing in, lemme tell you, its bright as hell. On top of growing something indica dominant that stays short and squat anyway, plus topping it, I can't imagine not getting very much bud. Especially if I keep them within 3x3 space as the manufacturer recommends. Like I said I haven't used it, but having seen it in action it is hard for me to believe.