Cannabis Watering Schedule: How Often to Water Weed

How often should you water a cannabis plant?

A cannabis watering schedule comes down to one rule: water when the top 1 to 2 inches of the medium feel dry. In soil that means every 2 to 4 days during veg and every 1 to 2 days in mid to late flower. In coco it means water once a day or every other day. The plant, pot size, and medium set the pace, not the calendar.

Cannabis watering schedule at a glance

• Seedling (week 1 to 2): 50 to 100 ml every 2 to 3 days, poured in a small ring around the stem.
• Early veg: water when the top inch is dry, about every 3 days in soil.
• Late veg: every 2 to 3 days in soil, until 10 to 20% of the water drains out the bottom.
• Early flower: every 2 to 3 days; thirst climbs as buds form.
• Mid to late flower: every 1 to 2 days in soil, up to twice a day in coco or rockwool.
• Flush (last 7 to 14 days): plain pH water on the same rhythm as late flower.

These ranges assume 3 to 7 gallon pots indoors at 75 to 80°F with 50% humidity. A 5 gallon pot of soil holds far more water than a 1 gallon, so pot size shifts the interval more than the strain does.

How do you know when a cannabis plant needs water?

Lift the pot. A soaked 5 gallon pot can weigh twice what a dry one does, and that weight test beats any timer. If the pot feels light and the top inch of medium crumbles in your fingers, it is time.

• Finger test: push a finger into the medium. Dry at 1 to 2 inches means water. Damp means wait.
• Pot weight: compare the pot right after a full watering with the same pot three days later. The difference is your target.
• Leaf angle: leaves that droop and feel soft and thin point to thirst. Leaves that droop and feel stiff and heavy point to too much water.
• Moisture meter: a cheap probe reads wet or dry at root depth, which helps in big pots where the surface lies.

Both overwatering and underwatering cause droop, so judge weight and texture rather than the look of the leaves alone.

How does water need change by growth stage?

Seedlings and clones

Small roots drink little. Water a small circle around the base and let the rest of the pot stay dry, which pushes roots to spread. Too much water in week one is the top reason seedlings stall.

Vegetative stage

Water use climbs as the canopy grows. A plant in late veg can drink a gallon every 2 to 3 days in a 5 gallon pot. Stop watering on a fixed day and start reading the pot.

Flowering

Water demand peaks in weeks 4 to 6 of flower, when buds bulk and the root ball fills the pot. Shorten your interval by a day, not by dumping in extra liters. Watering too often in flower invites mold and root rot.

Flush

Many growers switch to plain water for the last week or two. The plant still drinks the same volume, so keep the same pace and keep the medium from drying out.

Watering schedule by growing medium

• Soil: holds water and nutrients, so 2 to 4 days between waterings is normal. Let the pot dry a bit, since roots need oxygen.
• Coco coir: drains fast and holds no food, so most growers water once a day with nutrients and aim for 10 to 20% runoff. Never let coco dry out all the way.
• Peat and soilless mixes: between the two, so check weight and water every 2 to 3 days.
• Hydroponics and DWC: no schedule at all; the roots sit in aerated water 24 hours a day.

How much water does a cannabis plant need?

As a rule, pour 5 to 10% of the pot volume each time and let a little drain out the bottom. A 5 gallon pot takes about 1 to 2 liters to reach runoff. A 1 gallon starts at a quarter liter.

Volume matters more than timing. A bone dry pot that gets a splash stays dry at the bottom, and roots rot in the wet zone below while the top dries out. Water slow, in one pass, until the whole root ball is damp.

Does the schedule change outdoors?

Outdoor plants in the ground send roots deep, so they often go 3 to 5 days between waterings and handle a missed day without harm. Pots outside dry out faster than pots indoors, since wind and sun pull water from the surface. In a heat wave above 90°F, check a container twice a day.

Water quality, pH, and temperature

Cannabis in soil likes water between pH 6.0 and 7.0. Coco and hydro run lower, at pH 5.5 to 6.5. Tap water above 300 ppm of minerals can push your feed off balance, so let it sit overnight or run it through a filter.

Temperature matters too. Water between 65 and 75°F is the comfort zone. Cold water shocks roots and slows uptake. Hot water holds less oxygen.

Signs of overwatering vs underwatering

• Overwatering: droopy heavy leaves, slow growth, medium that never dries, algae on the topsoil, fungus gnats, brown slimy root tips.
• Underwatering: leaves that lag then crisp at the edges, medium that pulls away from the pot wall, a feather light pot, growth that stalls in the hours before droop.

Fix underwatering in hours: water slow and the plant perks within 30 to 60 minutes. Fix overwatering with patience, extra airflow, and no water at all until the pot gets light again.

Common cannabis watering mistakes

• Watering by the clock instead of by pot weight.
• Pouring a small sip each day, which keeps the top wet and the bottom bone dry.
• Letting coco dry out, which spikes pH and salt levels.
• Watering at lights off, when the plant drinks at a slower pace.
• Ignoring runoff, then blaming nutrients for burned tips.

FAQ: cannabis watering questions

Should I water cannabis every day?

Only in coco, rockwool, or a pot that has gone bone dry. Soil in a 3 to 7 gallon pot should go 2 to 4 days between waterings.

Do cannabis plants need less water in flower?

More, not less, until the last week or two. Water demand peaks around weeks 4 to 6 of flower and drops only when the plant stops swelling.

Is it better to water in the morning or at night?

Right after lights on. Leaves and medium dry through the day, which cuts the risk of mold on buds.

Can I water when the soil is still damp?

No. Roots need oxygen between waterings, and a medium that never dries is where pythium and root rot start.