by Lee G . Lyzit
Q
One of my cannabis plants ’ leaves are turning over to expose the down-facing side . The plant looks very healthy ( lots of rich green leaves , no spots ), and the other ones are growing normally . I thought that it was too close to the light , but I adjusted that and there ’ s been no change . Any thoughts ?
— Jacqueline Snyder a
Thank you for your question . There are several reasons why a cannabis plant ’ s leaves will turn over . Some are serious issues , while others can be easily corrected . This can be a frustrating problem , especially when the plant seems healthy otherwise . Perhaps the most common reason for leaves turning over on a cannabis plant is excess heat . Since you already adjusted the light , the intense heat from your artificial light source is probably not the culprit . However , if the ambient temperature of your garden is too high , the leaves can turn due to stress . Ideally , the temperature of your growroom while the lights are on should fall in the 20-27 ° C range and should drop no more than 5-10 degrees during the lights-off stage . Humidity could be a factor as well . Large swings in humidity levels can also cause leaves to twist , curl , or turn . Make sure you have consistent humidity levels in your grow area ; preferably in the 40-50 percent range ( vegetative growth can be a little higher ). Another cause of leaves turning , especially if it is happening in one specific area of the garden , is intense wind . Air movement in a growroom is crucial , but if a fan is too close or the air movement is too powerful , the plants can become stressed . If the plant you are having issues with is closest to a fan , I would suspect this is your problem . Light leaks during the dark period can also cause leaves to turn toward the unintended light source . Make sure you have a completely dark growroom during the lights-off period . When the lights are on , underside lighting or reflective material on the underside of the leaves can both cause the leaves to turn toward the light .
Side lighting is generally acceptable , but underside lighting or reflective materials should be avoided . Some nutrient deficiencies can cause the leaves to twist or turn as well . Generally , this would be accompanied by discolouration or wilting . However , during the early stages of a deficiency , the plants may exhibit leaf turn . Deficiencies in calcium and / or magnesium are commonly associated with this , so be sure these essential elements are available to your plants . Also , make sure to monitor and adjust your pH level . A pH level out of the desired range can lock nutrients out even when they are being supplied to the garden . For soil , a pH range of 6-6.8 will ensure calcium and magnesium are available for absorption . In hydroponic systems , a lower pH ( 5.5-6.0 ) is preferred . Residuals from foliar sprays have been known to cause the leaves to turn ; especially if the plant is sensitive to the ingredients in the spray . However , issues from foliar sprays would typically be universal throughout the plants and not just in a small section of growth . Lastly , insect pests , such as spider mites , can cause leaves to twist and turn . Examine your plants closely ; paying special attention to the underside of the leaves for eggs and larvae . If a pest insect is the issue , a treatment should be implemented immediately to negate further damage .
I hope this answers your question and helps resolve your issue .
Keep on Growing , Lee G Lyzit
LL
Lee G . Lyzit has been involved in the cannabis industry for nearly 20 years . His passion for natural healing motivates him to learn as much as he can about the miraculous cannabis plant . Lee ’ s knowledge of cannabis gardening stems from his own extensive cultivation experiences and his past work as a hydroponic shop owner and manager .
14 Maximum Yield