悟る · diagnose & fix
Cannabis Calcium & Magnesium (Cal-Mag) Deficiency
Nutrient deficiency · also: cal-mag deficiency, calmag, rust spots
Rust-colored spots and yellowing between the veins — the cal-mag combo deficiency common in coco and soft/RO water.
Not sure it's calcium & magnesium (cal-mag) deficiency?
Snap a photo and get a free read — no signup. Satoru weighs the visual against the conditions that cause look-alikes, so you treat the real problem.
What it looks like
Magnesium: yellowing BETWEEN the veins of middle/older leaves while veins stay green. Calcium: brown/rust spots, distorted or hooked new growth, weak stems. They often appear together.
Symptoms
- Interveinal yellowing (veins stay green)
- Rust/brown freckled spots on leaves
- Distorted or twisted new growth (calcium)
- Leaf edges curling or crisping
Causes
- Growing in coco coir (binds calcium)
- Reverse-osmosis or very soft tap water with no cal-mag added
- pH too low blocking uptake
- Heavy lighting/transpiration outpacing supply
How to fix it
- 1Add a cal-mag supplement, especially in coco or with RO water
- 2Verify pH is in range (5.5–6.5 hydro/coco) so cal-mag is available
- 3Don't over-correct — follow label dosing
Prevention
- Supplement cal-mag from the start in coco and with RO/soft water
- Maintain stable pH
悟る · how satoru tells it apart
Interveinal yellowing also shows in pH lockout and other deficiencies. Satoru factors your medium (coco vs soil) and water source — the two biggest cal-mag predictors — into the read.
Commonly confused with: pH Lockout, Potassium Deficiency, Nitrogen Deficiency.
Not sure it's calcium & magnesium (cal-mag) deficiency?
Snap a photo and get a free read — no signup. Satoru weighs the visual against the conditions that cause look-alikes, so you treat the real problem.
More plant problems
Educational reference for cultivation troubleshooting. Symptoms overlap — when in doubt, match against your own conditions. Satoru fuses your photo with your logged environment for a grounded read.