Short answer
Water when the top 2 to 3 inches of soil feel dry and the pot feels light. Leaves that droop and perk up within 1 to 2 hours after a watering need water. Leaves that droop and stay down 24 hours after a watering point to overwatering. Check the soil before you pour.
Signs the plant needs water
- Top 2 to 3 inches of soil are dry to the touch.
- The pot feels light when you lift it.
- Leaf stems and leaves sag, then lift after watering.
- Leaf edges turn crisp or brittle.
- Growth stalls and new leaves stay small.
- Soil pulls away from the inside of the pot.
Dry-soil droop shows up first on middle and lower leaves. A plant in a 5 gallon pot under strong light can use 1 to 2 gallons every 2 to 3 days in peak flower. Small pots dry out faster than large pots.
how often should i water cannabis plants
Signs of overwatering
- Leaves droop and stay droopy a full day after watering.
- Lower leaves turn yellow and drop.
- Leaf tips curl down.
- Soil stays dark and wet at the surface for days.
- Fungus gnats or green algae on top of the soil.
- Sour smell from the pot, a sign of root rot.
Overwatering pushes air out of the root zone. Roots need oxygen. A plant in wet soil for many days shows the same droop as a dry plant, so pot weight and soil moisture tell you more than the look of the leaves.
How Often to Water Cannabis During Veg
How to check soil moisture
- Push a finger 2 to 3 inches into the soil. Dry at the tip means water.
- Lift the pot. Note the weight when wet and when dry. Water at the light weight.
- Use a moisture meter. Read at 3 depths: top, middle, bottom.
- Check the drain holes. Water should flow out within 30 seconds of a slow pour.
Water amount and method
Pour until 10 to 20 percent of the water runs out the bottom. Empty the saucer after 30 minutes. Water the whole soil surface, not one spot. Let the pot drain before it goes back under the light. A plant in the ground needs 1 to 2 inches of water per week from rain or a hose.
Cannabis Watering Schedule: Soil vs Coco
Watering by stage
- Seedling: small amounts every 2 to 4 days in a 1 pint to 1 gallon pot.
- Vegetative: every 2 to 3 days in a 3 to 5 gallon pot.
- Flower: every 1 to 2 days in a 5 to 10 gallon pot under high light and low humidity.
These ranges are guides. Light intensity, temperature, humidity, pot size, and root mass change the number. Check the soil, not the calendar.
Common errors
- Watering on a set day instead of checking the soil.
- Small sips at the top of the pot. This leaves the lower roots dry.
- Letting the pot sit in runoff water.
- Adding water when the soil is still wet from the last round.