Could underfeeding in veg be causing nitrogen deficiency?

Plant is 3+ weeks old and growing fast. You're not feeding or using plain water. Fix: Start feeding a veg-stage nutrient (higher N) Week 3: ¼ strength. Week 4: ½ strength. Week 5+: full strength

Could ph lockout be causing nitrogen deficiency?

You ARE feeding but leaves are still yellow. Runoff pH outside 6.0-6.8 (soil). Fix: Measure runoff pH with a calibrated meter Flush with pH 6.5 water to reset

Nutrient IssuesModerate

Nitrogen Deficiency in Cannabis

Nitrogen is the most-used nutrient during vegetative growth. A deficiency shows up fast: pale green, then yellow, working up from the bottom leaves.

What it looks like

●Lower leaves fade from green to pale to yellow
●Yellow works UP the plant over time
●Whole leaf affected, not just veins or tips
●Leaves eventually drop off

Quick diagnostic checks

1If it's veg and leaves are yellow from the bottom, feed more N

2If it's late flower, some yellowing is NORMAL — don't feed

Causes ranked by likelihood

1. Underfeeding in veg

Most common

Signs

●Plant is 3+ weeks old and growing fast
●You're not feeding or using plain water

Fix

✓Start feeding a veg-stage nutrient (higher N)
✓Week 3: ¼ strength. Week 4: ½ strength. Week 5+: full strength

2. pH lockout

Common

Signs

●You ARE feeding but leaves are still yellow
●Runoff pH outside 6.0-6.8 (soil)

Fix

✓Measure runoff pH with a calibrated meter
✓Flush with pH 6.5 water to reset

⚠️When to worry

Severe N deficiency stalls growth. Left unfixed, it cuts yield 20%+. But mild fade in late flower is fine.

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