Short answer

Hydroponic cannabis grows with roots in water instead of soil. The simplest home setup is a deep water culture (DWC) bucket: a 5-gallon pail, a net pot, clay pebbles, an air stone, and an air pump. Seed to harvest runs about 10 to 14 weeks indoors.

cannabis hydroponics grow kit for beginners

Before you start

  • A legal check: confirm your state allows home cultivation and how many plants you may keep.
  • A sealed space: a closet or tent of at least 2 by 4 feet with room for a light and a filter.
  • Genetics: seeds or rooted clones from a licensed source.
  • Nutrients: a two or three part cannabis nutrient line plus a calcium and magnesium supplement.
  • Meters: a pH pen and an EC or PPM meter.
  • Light: LED or HPS sized for the footprint, plus a timer.
  • Air: an air pump, air stone, exhaust fan, and carbon filter for odor.

Step-by-step setup

  1. Confirm your plant count and mark the expected harvest week on a calendar.
  2. Set the bucket in the grow space and hang the light 24 to 30 inches above the net pot.
  3. Fill the reservoir with 4 gallons of water and let it sit 24 hours so chlorine dissipates.
  4. Add nutrients at one quarter of the label strength for a seedling or a fresh clone.
  5. Stir the solution for a minute, then read the EC.
  6. Adjust pH to between 5.5 and 6.5 with pH up or pH down.
  7. Drop the air stone into the bucket and plug in the pump so the water stays oxygenated.
  8. Place the rockwool cube with the sprouted seed into the net pot and fill around it with rinsed clay pebbles.
  9. Set the timer to 18 hours on and 6 hours off for the vegetative stage.
  10. Top off the reservoir with plain water every two days and check pH each time.
  11. Drain and replace the full reservoir every 7 to 10 days.
  12. Switch the timer to 12 hours on and 12 hours off when you want flowering to begin.
  13. Inspect trichomes with a loupe and harvest when most are cloudy with a few amber.

Common problems

  • Root rot: slime and a sour smell mean the water is too warm. Keep the reservoir below 70 F.
  • Nutrient burn: curled, browned leaf tips mean the EC is too high. Dilute the reservoir by half.
  • pH drift: nutrient uptake moves pH, so measure daily during flower.
  • Light stress: bleached top leaves mean the lamp is too close. Raise it 6 inches.

Legal note

Cannabis cultivation rules differ by state, and home growing remains illegal in some states. Check your state program before you buy equipment.

how to start cannabis hydroponics at home