Nutrients/Various Problems
Nutrient Deficiencies - Nutrient deficiencies in modern gardens are really rare. What most people see as a ‘Nutrient Deficiency’ is, 9 times out of 10, a pH problem. A pH that is too high or too low ‘locks out’ your plants ability to uptake nutrients. Since the plant can not uptake those nutrients they appear to be deficient. When in fact, there are plenty of nutrients in the solution/soil but, due to pH Lock-out, they are unavailable to the plant. Adding supplements or more nutrients (which is what most do) will only compound this problem by throwing the pH off even more and further raising the nutrient PPM. The best thing to do if you suspect ANY form of nutrient deficiency is to check and adjust the pH as necessary. The proper pH ranges for both hydroponics & soil is shown in the chart below. Pay particular attention to the ranges that certain nutrients are available and when they are locked out.
Over Watering - Signs of over watering include: Leaf wilting/drooping and Chlorosis (Leaf Yellowing). Also, smelly soggy soil is another indication in soil gardens.
Solution - Increase the temperature and airflow to evaporate some of the excess water. Also, you can add some h2o2 when watering to help the roots still receive O2. And just don’t water as much. You should only water when your soil/medium is dry. If you have smelly soggy soil the best thing to do is transplant it into fresh dry soil.
Over Fertilizing - Signs of over fertilization include: dead/burnt leaf tips/margins and leaves curling under.
Solution - Check and adjust the pH level as necessary. Flush and decrease the fertilizer/nutrient level.
pH Problems - pH problems can manifest it self in many different ways. Anywhere from: nutrient deficiencies to over fertilization and leaf burn. The key to telling which you have is, knowing your pH.
Solution - Check and adjust the pH level as necessary.
Root Bound - See root bound below in the Root Problems section.
Heat Stress - Signs of heat stress can look a lot like nutrient burn, except it occurs only on the top of the plant closest to the lamps. A yellowing of the upper leaves is usually a bleaching from being too close to HID lights.
Solution - A good test to see if your lights are too close is to put your hand between the light and the plant. If your hand gets too hot for comfort, the light is too close and needs to be moved up higher.
Leaf Problems
Yellowing (Chlorosis) - Chlorosis is a yellowing of leaf tissue due to a lack of chlorophyll. Possible causes of chlorosis include poor drainage, damaged roots, compacted roots (see Root Bound below), high alkalinity, and nutrient deficiencies. Nutrient deficiencies may occur because there is an insufficient amount in the soil or because the nutrients are unavailable due to a high pH. **Note- Always check the pH before increasing nutrient level. In the last few weeks of flowering a yellowing of the leaves is completely normal as the plant uses up all stored nutrients.
Yellowing - Lower/Middle Leaves - Yellowing of the lower leaves/older growth is a sign of a possible Nitrogen (N) deficiency. Nitrogen is a transferable element (this means the plant can move it around as needed). If a plant is not receiving enough Nitrogen from the roots then it will rob Nitrogen from the older growth. Plants that are Nitrogen deficient will exhibit a lack of vigor and grow slowly resulting in a weak and stunted plant that is significantly reduced in quality and yield. In a Hydroponic system, usually the pH is too high and has locked out the available Nitrogen. In soil a yellowing of the lower leaves could also be an indication of a root bound plant (see Root Bound below).
Solution - First, check the pH, and adjust if necessary. The correct pH for marijuana is 6.3 - 6.8 in soil and 5.5 - 6.1 in a hydroponic system. Second, make sure you are giving the correct amount/type of fertilizer/nutrients. For the vegetative stage of growth marijuana needs a fertilizer/nutrient with a high Nitrogen (N) content like 2-1-1 (or 20-10-10).
Yellowing - Upper (New Growth) - Yellowing of the upper (new growth) of the plants could be a sign of a Sulphur (S) deficiency. Sulphur deficiency is pretty rare but usually start off as a yellowing of the entire ‘younger’ leaf including the veins. Other signs of sulfur deficiency are: Elongated roots, woody stems, and Leaf tips curling downward. **Note- Most yellowing of the upper leaves is a bleaching from being too close to the lights.
Solution - Check and adjust the pH level as necessary. Check your fertilizer/nutrient levels and make sure you are giving the correct amount/type for you particular stage of growth. Also a good test to see if your lights are too close is to put your hand between the light and the plant. If your hand gets too hot for comfort, the light is too close and needs to be moved up higher.
Leaf Curling Up - Leaf curling up can be a sign of a Magnesium (Mg) deficiency caused by too low of a pH level. Magnesium deficiency will show as a yellowing (which may turn brown and crispy) and interveinal (in between the veins) yellowing beginning in the older leaves. Interveinal chlorosis (yellowing) will start at the leaf tip and progressing inward between the veins. It could also be a sign of excess heat and humidity in the grow room.
Solution - Check and adjust the pH level as necessary. When the pH is not at the proper level marijuana will lose its ability to absorb some of the essential elements required for healthy growth. If you’re growing in soil Magnesium will begin to be locked out at a pH of 6.5 and lower, in hydro it starts at 5.8 and below. If the pH is correct, then add 1 teaspoon of Epsom salts per each gallon to your water. Or, to foliar feed them, add a ½ teaspoon per quart to a spray bottle. **Note- If your tap water is over 200 ppm Magnesium will be locked out due to the calcium in the water. Magnesium can get locked out by too much Calcium (Ca), Chlorine (Cl) or Ammonium Nitrogen (NH4+). If this is your problem we suggest using bottled or RO (reverse osmosis) water.
Leaf Curling Down - When the leaves curl under and burn at the tips and margins it’s usually a sign that the nutrient level is too high.
Solution - Check and adjust the pH level as necessary. Flush and decrease the nutrient level.
Droopy Leaves - Leaves that are drooping are most likely caused by over watering/under watering or lack of light.
Solution - First off, for soil, Place you finger into your soil a few inches and see if it's dry or wet. If over watering is your problem, increase the temperature and airflow to evaporate some of the excess water also you can add some h2o2 when watering to help the roots still receive O2. **Warning!- Chronic over watering can lead to soggy roots and stagnant, icky soil. if you slide the plant out of the pot to check the soil and it stinks or is soggy then transplant into fresh dry soil. For a hydroponic system, check to see if your medium is dry or wet before you water (or your pump comes on). If your medium is still pretty wet, then you are over watering and need to water less often. If your medium is very dry before watering, under watering is your problem, just water more frequently. And lastly, If lack of light is the problem, Add more light.
Root Problems
Root Bound - Root bound is where the roots of your plant outgrow the container they are potted in. Plants that are root bound exhibit stunted growth, stretching, smaller and slower bud production, easier to burn with nutrient solution, needs watering too often, and wilting. A root bound plant will always start yellowing with the bottom leaves and work its way up the plant until all the fan leaves are gone.
Solution - To fix this problem you need to transplant your plant into a bigger pot. The 'rule of thumb' with soil is 1 gallon of soil for every foot of growth except for clones which can use a smaller size. So a 2' tall plant is going to need AT LEAST a 2 gallon container. First thing you need to do is gently remove your plant from it’s smaller container. While it’s out, inspect its roots, if the roots run in a tight circle around the outside of the root ball, you caught it just in time. Very carefully use your fingers to dig into the outside 1/2" of these circular roots, loosen them up and pull them gently (yes, I said gently ) outward. If the roots are extremely tight, you can VERY carefully slice a thin layer (less then a ½") off the outside of the entire root-ball. Once you have tended to the roots It’s time to replant it. Set the now un-bound root-ball into its new larger pot.**Note- Do not pack down this new soil, you want the soil to be settled (with no air pockets) but loose enough to allow the roots to easily penetrate it.
Stunted Roots - Stunted roots (slow or no new root growth) is could be caused by a calcium deficiency, aluminum toxicity, copper toxicity, pH acidity, or soil toxicity.
Solution - As always check and adjust the pH level as necessary. If soil toxicity, of any kind, is your problem then you need to flush it real good.
Stem Problems
Stem Breakage - Everyone from time to time has had this problem or will. This is when your stem is broken. Stem breaks can come from a number of things: training, dropping something on it, animals, weather. No matter how it happened the most important thing is to not panic.
Solution - Fixing this is not really a problem. Splint it with something and tape it in place. Marijuana has a great ability to come back even after a stem break. Give her a week or so to recover before she will start to grow again. And be more careful next time!
