Back. 1  Vitacost Chromium Picolinate -- 500 mcg - 300 Capsules. 4.5 out of 5 stars 11. 2  Vitacost Strontium -- 680 mg per serving - 240 Vegetarian Capsules. 4.6 out of 5 stars 19. 3  Vitacost Glucomannan -- 2000 mg per serving - 180 Capsules. 3.7 out of 5 stars 51.
The most common cause of marijuana leaf cupping aka leaf margin rolling, leaf margin burn, and leaf tip curl/burn is overzealous use of marijuana plant food. In relationship to factors such as marijuana plant vigour and rate of growth. Leaf burn is often the very first sign of too much marijuana fertilizer.
When Cannabis plants are exposed to excessive heat, the serrated edges will tend to fold inwards. The same thing is seen when the plants are too close to the grow lights as this tends to create hot spots. You should also look out for humidity as this is a reason why the Cannabis leaves tend to curl sometimes. There is a difference however when the leaves of the plant curl as a result of low humidity. In the latter, the curling often causes the leaves to fold at the centre, and will most certainly resemble a taco.