Common Marijuana Plant Growing Problems
Common Marijuana Plant Problems
TIP #8
Are your marijuana plants showing signs of problems? Discoloration, blotches, drying up, and wilting are just some of the ways the leaves of a marijuana plant will let you know something is wrong. They are not as happy as they would like to be. Stressing the marijuana plant can lead to low yield or even its demise. First rule out these things:
- Plants have plenty of water
- PH is 5.6 – 5.9
- Your light cycles are correct
- Your medium is not saturated
- Constant fresh air
With the above ruled out, use the below to help diagnose your plants problem!
Bigger leaves are turning a yellowish color while the smaller leaves are green.
- Nitrogen deficiency – add nitrate of soda or organic fertilizer.
Older leaves will curl at edges, turn dark, possibly with a purple cast.
- Phosphorous deficiency – add commercial phosphate.
Mature leaves develop a yellowish cast to least veinal areas.
- Magnesium deficiency – add commercial fertilizer with a magnesium content.
Mature leaves turn yellow and then become spotted with edge areas
turning dark gray.
- Potassium deficiency – add muriate of potash.
Cracked stems, no healthy support tissue.
- Boron deficiency -add any plant food containing boron.
Small wrinkled leaves with yellowish vein systems.
- Zinc deficiency – add commercial plant food containing zinc.
Young leaves become deformed, possibly yellowing.
- Molybedum deficiency – use any plant food with a bit of molybdenum in it.

March 9th, 2009 at 4:36 pm
I have six HOG plants in my cab right now. One showed up with powdery mold so I raised the lights cut them off early and hit them with a mist of neem soap and water.cool. well the next day one of them has significant black necrotic looking patches all over and is rapidly yellowing (just the fan leaves). Have any clue on the possible problem? It doesn’t doesn’t fit the common Disease and Def. tables I’ve looked at. I’ve since isolated this plant away from the rest and it looks like iy’s going to die in a few days if I don’t find a solution. They all get F.F. nutes and are in Ocean forest/ Verm/ and per mix. Please help.
March 14th, 2009 at 6:36 am
how old is the plant? is the same plant that showed mold or a different? whats the humidity of room? are the patches in the leaf or is it smearable like its on the leaf? make sure to let your soil dry out considerably. you should get 2 knuckles deep of dry soil between waterings.
August 2nd, 2009 at 3:35 am
hi need help i got 3 autoflowerinf wight russain 1 is 6weeks and well into bud all the leafs started getting black spots arouned edges and pointes curling up 1 is at 5 week and leafs r getting yellow spots and poinets r turning brown the 7week looks good