by Lee G . Lyzit
Q
What ’ s the reason for marijuana plant leaves to curve at the tips ? Thanks . — Rob K . a
Hey Rob ! Thank you for your question . There are actually a few different reasons that a cannabis plant ’ s leaves will curve at the tips . Marijuana leaf tip curl , also known as clawing , is most commonly caused by overwatering or over-fertilization . When I worked at an indoor gardening centre , we called this “ loving your plants to death .” In other words , it can be harmful to give marijuana plants too much of a good thing .
Overwatering
Leaf curl , or clawing , can be the first indicator that cannabis plants are being overwatered . The damage from overwatering occurs in the plants ’ roots , due to a lack of oxygen . To remain healthy and uptake nutrients , the roots of marijuana plants need access to fresh oxygen . Along with the roots themselves , the beneficial microorganisms in the soil or medium also require oxygen to function properly . In fact , most beneficial microorganisms in the soil are referred to as aerobic organisms , meaning they survive and grow in oxygenated environments . On the other hand , pathogenic organisms , such as pythium , which negatively affect a cannabis plant ’ s roots , are anaerobic organisms and thrive in environments that lack oxygen . By overwatering marijuana plants , an anaerobic environment is created around the roots , thus hindering beneficial microorganisms and catering to anaerobic organisms . To rectify this problem , a grower should allow the soil or medium to thoroughly dry out between watering . This allows fresh oxygen to reach the roots . It is also a good idea to amend a soil or medium with aerating ingredients , such as pumice or perlite .
Over-fertilization
Besides overwatering , another common cause of cannabis leaf curl is over-fertilization . One of the initial signs of overfertilization is leaf curl on the tips of the marijuana leaves .
If the curl is accompanied by a very dark green leaf colour , then too much nitrogen is the culprit . If caught early enough , the problem can be fixed by simply reducing the concentration of fertilizer that is being used . More extreme over-fertilization cases may exhibit leaf curl combined with burnt edges of the leaves . In this case , the grower will need to flush a lot of pure water through the medium to remove the excess salts . This will require watering at least two to three times the volume of the planting container . For example , a five-gallon ( 19-litre ) container would need 38-57 litres of water to flush the medium .
Other Possible Reasons for Marijuana Leaf Curl
Although not as common as overwatering and overfertilization , there are other reasons a marijuana plant ’ s leaves may curl . Extreme temperatures ( both too cold or too hot ) can cause leaf curl on cannabis plants . Artificial lighting that is too close to the leaves can also cause a leaf curl effect . However , this is usually coupled with other tell-tale signs of light burn , such as white pigmentation or scorching of the vegetation . Lastly , wind burn can cause cannabis leaves to curl . For indoor plants , this can be corrected by repositioning fans to reduce the stress caused by too strong a wind .
Leaf curl , or clawing , is a common , early indicator of an issue in a cannabis garden . As long as the source of the problem is identified and rectified in a timely manner , the plants can usually fully recover . I hope this answers your question .
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 .
16 Maximum Yield