Overwatering

Overwatering is not about how much water you pour. It is about how often. Roots need oxygen as much as they need water, and soil that stays wet has no air in it, so the roots stop working and the plant above them starts to fail.

What you are seeing#

The first sign is drooping, but a specific kind. The whole plant sags from the stem out, leaves curling down over themselves, and the leaves feel firm and heavy when you pinch them rather than limp and papery. Growers call it the overwatered taco, the leaf folding down and inward.

Next comes slowness. New growth stalls for days at a time and the plant sits there not getting bigger. Then the lower leaves start to yellow and drop, because roots that cannot breathe cannot pull nitrogen out of the soil even when the soil is full of it.

Push a finger two inches into the medium. If it is wet down there and you watered yesterday, that is your answer. Lift the pot too. An overwatered pot stays heavy for days and never gets light.

Why it happens#

Beginners water on a schedule instead of on weight, usually every day or every other day because that is what houseplants get. Cannabis in a three or five gallon pot does not need that.

The other causes stack on each other. A small plant in an oversized pot takes weeks to drink the soil around it. A plastic pot with poor drainage, or a saucer that stays full, keeps the bottom third soaked. Soil heavy on peat and light on perlite holds water like a sponge. Tent temperatures under 70F slow evaporation. Any two of those together and you overwater without adding a drop more than your neighbor does.

How to fix it#

1. Stop watering today. Do not water again until the top two inches are dry and the pot feels noticeably light. In a 3 gallon fabric pot that is usually 3 to 6 days, not 1.
2. Empty the saucer and run a fan low across the surface of the medium, not into the leaves. Moving air over the top speeds drying by a day or more.
3. Get the tent to 75 to 80F during lights on. Cold soil stays wet.
4. Water by weight from now on. Lift the pot right after a full watering, then lift it daily, and water again when it feels close to its dry weight.
5. Water properly when you do. Soak until 10 to 20 percent runs out of the bottom, then stop. Small daily sips keep the top wet and the bottom stale.
6. If it keeps happening, fix the pot. Repot into fabric, and cut your next batch of soil with 20 to 30 percent perlite.

How to tell it apart#

Versus underwatering. Both droop. The difference is in your hands. Overwatered leaves are firm, thick and curled downward, and the pot is heavy. Underwatered leaves are thin, limp and papery, and the pot is light. Lift the pot before you diagnose anything else.

Versus root rot. Overwatering leads to root rot but is not the same thing yet. Pull the plant partway out of the pot and look. White or cream roots with a clean earthy smell means you caught it at overwatering. Brown, mushy, sour smelling roots means the rot has started and the response is more aggressive.

Versus nitrogen deficiency. Nitrogen deficiency yellows from the bottom up with no drooping, and leaves stay flat as they fade. Overwatering droops first and yellows second.

How long until it looks better#

Drooping lifts fast once the soil dries. Most plants stand back up within 24 to 48 hours of a proper dry-back, some in a few hours.

Yellow leaves do not turn green again. That tissue is spent. Judge recovery by new growth at the top, which should look normal within 4 to 7 days of the first correct watering cycle. If you still see droop after a full dry-back, stop treating it as overwatering and check the roots.