How to identify Cannabis Nutrient Deficiency in 13 steps or less
- a) If the problem affects only the bottom or middle of the plant go to #2.
b) If it affects only the top of the plant or the growing tips, skip to #10.
c) If the problem seems to affect the entire plant equally, skip to #6.
- Leaves are a uniform yellow or light green; leaves die & drop; growth is slow. Leaf margins are not curled-up noticeably.
>> Nitrogen(N) deficiency.
If not, go to #3.
- Margins of the leaves are turned up, and the tips may be twisted. Leaves are yellowing (and may turn brown), but the veins remain somewhat green.
>> Magnesium (Mg) deficiency.
If not, go to #4.
- Leaves are browning or yellowing. Yellow, brown, or necrotic (dead) patches, especially around the edges of the leaf, which may be curled. Plant may be too tall.
>> Potassium (K) deficiency.
If not, keep reading.
- Leaves are dark green or red/purple. Stems and petioles may have purple & red on them. Leaves may turn yellow or curl under. Leaf may drop easily. Growth may be slow and leaves may be small.
>> Phosphorus(P) deficiency.
If not, go to #6.
- Tips of leaves are yellow, brown, or dead. Plant otherwise looks healthy & green. Stems may be soft
>> Over-fertilization (especially N), over-watering, damaged roots, or insufficient soil aeration (use more sand or perlite. Occasionally due to not enough N, P, or K.
If not, go to #7.
- Leaves are curled under like a ram’s horn, and are dark green, gray, brown, or gold.
>> Over-fertilization (too much N).
If not, go to #8…
- The plant is wilted, even though the soil is moist.
>> Over-fertilization, soggy soil, damaged roots, disease; copper deficiency (very unlikely).
If not, go to #9.
- Plants won’t flower, even though they get 12 hours of darkness for over 2 weeks.
>> The night period is not completely dark. Too much nitrogen. Too much pruning or cloning.
If not, go to #10…
- Leaves are yellow or white, but the veins are mostly green.
>> Iron (Fe) deficiency.
If not, go to #11.
- Leaves are light green or yellow beginning at the base, while the leaf margins remain green. Necrotic spots may be between veins. Leaves are not twisted.
>> Manganese (Mn) deficiency.
If not, #12.
- Leaves are twisted. Otherwise, pretty much like #11.
>> Zinc (Zn) deficiency.
If not, #13.
- Leaves twist, then turn brown or die.
>> The lights are too close to the plant. Rarely, a Calcium (Ca) or Boron (B) deficiency. b) If not… You may just have a weak plant… Send us a message and we’ll try to help you out!