Answer: This plant is showing classic signs of root problems like root rot. The fact that your plant is drinking less than normal also seems to indicate that there's a problem at the roots. When the whole plant seems to just "deflate" overnight, it's often caused by root problems. Heat can be a trigger (root bacteria love warm temps) and will also make this problem worse.
Root problems often hit growers in soil or coco coir soon after the flip to the flowering stage, especially with less powerful lights like CFLs. This is because plants use a lot more water when they're receiving 24 hours of light a day. When you flip to 12/12 light for the flowering stage, it's easy to overwater plants if you continue watering them on the same schedule. It's important to user proper watering practices throughout your grow. If you think you may have root problems, there are two easy ways to deal with this. 1.) You can purchase Hydrogen Peroxide in 3% – 35% strength. Mix 1 cup of 3% Hydrogen Peroxide with a gallon of water.
For 35% strength Hydrogen Peroxide, mix one tablespoon to a gallon of water. Water your plants with the mixture to kill any bacteria living in your root area. Unfortunately, hydrogen peroxide also kills good bacteria, which can protect your plant from future infections. 2.) (My prefered method) Conversely, you can start adding Aquashield to your nutrient-water when you feed. This will build up colonies of good bacteria that out-compete the bad bacteria and actually promote plant growth. In addition, the beneficial bacteria will offer protection for those times when the temperature of the grow area rises at a time when you can't control it. When I first got started with bubbleponics, I had a few tough bouts with root rot. Over the last few years, I've tried many "good bacteria" products including the ($$$) Great White and Subculture B additives, but no product has ever worked 1/4 as good at maintaining healthy roots as super cheap, readily available Aquashield. My soil / coco coir / growing medium seems to stay wet no matter what. If plant medium seems to stay wet no matter what you do, you may need better drainage . It may also help to move plants to a smaller pot until they get bigger and start drinking more. Make sure that water drains freely from the bottom of your container (it's recommended that you provide enough water to get at least 20% extra runoff every time you water your plants). You should see water coming out the bottom within a minute or two after watering. Then don't water your plants again until the soil is dry up to your first knuckle. For soil / coco coir grows, you generally only want to water the plant when the soil feels dry if you press a finger in it. You can also use the "lift the pot" method to decide when to water your plants (basically wait until your pot feels "light" since the plants have used up all the water). For other growing mediums besides soil, your watering method will vary, but if your plants are drooping and you've been feeding them a lot of water, it's a good idea to cut back and see if that helps. If your plants are already overwatered, you can try to increase airflow to help the water evaporate more quickly. You can also use a pencil to gently poke some air holes into the growing medium to provide extra aeration and oxygen to the roots. Some growers will even replant a heavily overwatered plant, to get some oxygen immediately to the roots. Problem: After watering, your plants start drooping. Usually the droopy leaves will feel firm and appear curled down (the whole leaf will be curled, not just the tips, which is often a sign of nitrogen toxicity). With overwatered cannabis plants, you may also notice Chlorosis (leaf yellowing that is similar to a nitrogen deficiency).
Overwatered cannabis plants are droopy with leaves that curl down. As a result of overwatering, leaves often turn yellow or show other signs of nutrient deficiencies (especially when it comes to younger plants and seedlings!) Overwatering does not always mean you’ve been giving the plant too much water. It can also mean that you’ve been giving the plant water too often , or growing plants in a growing medium that holds onto water without enough air, or doesn’t have good drainage out the bottom. Cannabis plants use their roots to get oxygen, almost like they’re breathing. Oxygen is dissolved in water, and there’s also air pockets in their grow medium to provide a source of oxygen. When you water your plants too often, the roots end up sitting in stagnant water. The reason your plants droop is because basically their roots are starving for oxygen. This sick marijuana seedling has several symptoms including droopiness and leaves with brown spots that appear to be a nutrient deficiency. Surprisingly, the true cause of both problems actually is the thick, wet, muddy soil. The main sign of a cannabis plant being overwatered are the droopy leaves, though other symptoms often appear around the same time!
Drooping / Curling is the first sign of overwaterd marijuana plants Plants start drooping soon after watering Leaves are firm and curled down all the way from the stem to the leaf Will eventually lead to leaf yellowing and other signs of nutrient problems if not corrected. The drooping cannabis plant below did not have drainage holes (water could not drain out the bottom of the pot). After watering the plant which appeared healthy the night before, the grower came back to this drooping plant the next day – this case of overwatering was caused by too much water being held near the roots due to lack of drainage: Solution: The best thing you can do for overwatered plants is give them time between waterings, and then start off watering slowly until things seem back to normal.