How to Grow Cannabis Indoors for Beginners

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A beginner can grow cannabis indoors with four items: a tent, a light, an exhaust fan with a carbon filter, and a pot of soil. Keep the room at 70-80°F. Run the light 18 hours on and 6 off. Water when the top inch of soil feels dry. Drop to 12 hours of light to start flowering. A basic 2x2 ft setup runs $300 to $600.

how to grow cannabis indoors for beginners

1. Pick autoflower or photoperiod seed

Autoflower plants flower on a fixed schedule. Seed to harvest takes 70-90 days. Photoperiod plants flower when the light schedule drops to 12 hours on and 12 off. Photoperiod gives you control and bigger yields. Autoflower is the simpler first run.

Common Cannabis Growing Mistakes and How to Avoid Them

2. Pick a space

One plant needs about 2 square feet of floor. A 2x2 ft tent holds one plant. A 4x4 ft tent holds four. A closet works if the door closes and blocks light. The room must go dark during the 12-hour flower cycle. A light leak can stall flowering.

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3. Set the light

LED boards are the standard. Plan on 30 to 40 watts of LED per square foot of canopy. A 2x2 ft tent needs 120 to 160 watts. Hang the panel 18 to 24 inches above the plant tops. Raise it as plants grow.

4. Pot and soil

Use a 3 to 5 gallon fabric pot. Fabric pots air-prune roots and dry out faster than plastic. A peat or coco mix with perlite drains well. Fill the pot to 1 inch below the rim. Set water pH to 6.0-6.5 for soil.

5. Water and feed

Water until a little runs out the bottom, then wait. Lift the pot to check weight. A 3 gallon pot in veg drinks about a quart every 2 to 3 days. Feed at half the label rate at first. Too much nutrient burns leaf tips.

6. Move air

Add a 4 inch inline fan and a carbon filter. The filter removes the smell. A small clip fan moves air across the canopy and thickens stems. Target 40-60 percent humidity in veg and 40-50 percent in flower.

7. Flip, then harvest

Photoperiod plants need 4 to 8 weeks of veg, then 8 to 10 weeks of flower. Check trichomes with a jeweler's loupe. Cloudy trichomes mean peak THC. Clear means early. Amber means past peak. Cut the plant at the base and hang it whole at 60-70°F and 45-55 percent humidity for 7 to 14 days.

Common beginner mistakes

• Overwatering. Wet roots stall growth.
• Full-strength nutrients on the first feed.
• No exhaust fan. Smell escapes and heat builds.
• Light too close. Bleached tops mean heat stress.
• A light leak during flower.

Check your state law

Home grow rules differ by state. Some states allow a set plant count. Some allow none. Confirm the plant limit and the rules on where plants can sit. A plant in public view can be a violation even where home grow is legal.