CannaGLAP

Cannabis grow problem library

Yellow leaves, burned tips, speckles, powder, droop. Find what your plant is telling you, how to fix it, and organic options, with Cannie showing each one early and advanced.

Start here: check your pH before you add anything. Most "deficiencies" are a nutrient the plant cannot take up, not one that is missing. Soil 6.2 to 6.8, coco or hydro 5.8 to 6.2.
Where nutrient problems show: old lower leaves for N P K Mg, new top growth for Ca Fe S Zn Mn B
Where it shows halves the list before you read a word.
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Every deficiency on one page: where it starts on the plant and what the leaf looks like. Print it and pin it by the tent.

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Nutrient deficiencies

Nitrogen deficiencyOldest, lowest leaves first, working upward.Phosphorus deficiencyLower leaves and their stems.Potassium deficiencyLower leaves, around the whole outer edge.Magnesium deficiencyLower and middle leaves.Calcium deficiencyNew growth at the top. Old leaves stay fine.Iron deficiencyThe very newest growth at the top, dramatically.Sulfur deficiencyNew growth at the top, the opposite of nitrogen.Zinc deficiencyNew growth, as a spacing problem rather than a color one.Manganese deficiencyNew growth at the top.Boron deficiencyThe growing tip itself, which stops and dies back.

Too much feed

Nutrient burnLeaf tips, across the whole plant.

Watering problems

OverwateredThe whole plant droops.UnderwateredThe whole plant droops.

Pests

Spider mitesLeaf undersides first, then webbing everywhere.ThripsUpper leaf surfaces.AphidsStems and leaf undersides, in visible clusters.Fungus gnatsFlying around the medium surface, not the canopy.

Mold and rot

Powdery mildewUpper leaf surfaces, as distinct circular patches.Bud rot (botrytis)Inside dense flower, hidden. Not on the surface.Root rotThe whole plant, as an unexplained decline.