Plants droop from too much light
Drooping leaves on a cannabis plant can be caused by a few different issues and will be a plant problem for many people during cultivation. An experienced grower will know the main factors that cause drooping leaves but we will quickly cover all the reasons below. If you are certain the leaves are drooping due to too much light (you will know for sure by checking the leaves during the dark period and seeing if they droop or stand strong), then you may want to skip the paragraph below.
Before a grower starts making any changes to their light or light schedule, they should ensure these common issues below are not the cause of the problem.
Other reasons for leaves drooping
- Over watering or under watering
- Nutrient deficiency
- Grow room temperatures incorrect
- cold roots
Both of these symptoms look the same, but checking the medium will make it obvious as to which is the issue. In extreme cases watering issues can even cause the stem to go floppy and limp.
The leaves can droop from nutrient deficiencies, but there will always be bad leaves combined with the droop.
Generally, temperatures should be between 75F to 85F for lights on and about 65F to 70F light off. Whilst the top of the plants might be the correct temperature, the rest of the plant might be cooler below the canopy.
Even when the grow room temperatures are correct, the roots could be too cold. This can cause a number of issues such as stunted growth or drooping leaves. If using air pots then wind movement from fans could be causing cold roots. Simply making a barrier around the pots with cardboard could help solve this problem. Also, ensure the water is room temperature or slightly warmer as anything cold will make the problem much worse.
Are drooping leaves a problem
Drooping leaves are not always an issue and can sometimes be ignored. Some strains can just droop more than others yet yields and quality will still be top class. But trying out a few small changes can still make those leaves stand up stronger.
Fixing drooping leaves caused by too much light
If all of the points above are in check and not causing the issue, then it is most likely an issue with the light or light schedule. To be 100% sure, the grower can check the leaves 2 minutes before the lights come on. If the leaves are still drooping at the end of the dark period then too much light is not the problem.
Firstly, the light schedule needs to be looked at. If using a photoperiod plant the light schedule is normally 18 hours on and 6 hours off (for veg). Some growers use 20 hours on, if leaves are drooping then pull the light schedule back to 18/6 and check the difference after a few days. For flower always stay at 12/12.
Using too much light in a small space can cause light burn where the leaves loose their green colour and turn white. Check all leaves at the top of the plant for this. Moving the light further away from the plants will fix the issue. Another symptom could also be the drooping leaves. Instead of moving the light further away you may be able to dim the light using a dial (many LED lights and digital ballasts have this). Check for results after a few days.
After reading this guide a grower can easily confirm whether or not too much light was the problem. If it is the problem, then the two paragraphs above explain how to fix it.
Even if the problem is not fixed it does not often cause major problems. Many indica strains or plants with landrace genetics in them tend to droop their leaves during growing and/or flowering.