How to Grow Weed Indoors: Complete Beginner Guide

What You Need (Equipment List)

Indoor growing requires an upfront investment, but a basic setup doesn't have to break the bank. Here's the minimum viable grow room for a first-time grower running 1–2 plants.

Setting Up Your Grow Space

Tent placement: Choose a location with access to a power outlet, where the tent won't be in direct sunlight or against a heat source. A closet, spare room corner, or basement works well. The floor should be easy to clean in case of spills.

Light height: LEDs typically hang 18–24 inches above the canopy during veg and 12–18 inches during flower. Start high and lower gradually — if leaf tips curl upward or bleach white, the light is too close.

Ventilation setup: Mount the inline fan at the top of the tent (hot air rises), with the carbon filter attached inside the tent. This creates negative pressure — air flows in through passive intake vents at the bottom and gets exhausted through the fan, passing through the carbon filter to eliminate odor.

Temperature and humidity targets: During veg, aim for 70–80°F and 50–70% humidity. During flower, aim for 65–80°F and 40–50% humidity. A small clip fan inside the tent provides air movement and strengthens stems.

Germination and Seedling Stage

Start seeds using the paper towel method described in our seed guide. Once the taproot is 1/4–1/2 inch long, plant it taproot-down in a small starter pot (12–16 oz cup with drainage holes) filled with pre-moistened soil. Cover lightly with soil — about 1/2 inch deep.

For the first 7–10 days, the seedling needs gentle conditions. Run your light at 50% power or raise it higher than normal. Humidity should be 65–70%. Water sparingly — the biggest seedling killer is overwatering. Water once at planting, then don't water again until the soil feels dry when you stick your finger an inch deep.

Light schedule for seedlings: 18 hours on, 6 hours off. This applies whether you're growing autoflowers or photoperiod plants. Some growers run autoflowers on 20/4 or even 24/0, but 18/6 is the sweet spot for beginners — the plants get a rest period without sacrificing growth.

Vegetative Growth

Veg starts once the seedling develops its first set of true leaves (the serrated, multi-fingered leaves that look like cannabis, not the initial round cotyledons). This stage lasts 3–6 weeks for autoflowers, or as long as you want for photoperiod plants.

Watering: Follow the lift test — pick up the pot. Heavy = don't water. Light = water until you see 10–20% runoff from the bottom. Then wait until it feels light again. This wet-dry cycle is essential for healthy root development.

Nutrients: If you're using pre-amended soil (like Fox Farm Ocean Forest), your seedlings won't need additional nutrients for the first 3–4 weeks. After that, start with 1/4 to 1/2 strength vegetative nutrients (higher nitrogen). Watch for dark green leaves (overfed) or pale, yellowing lower leaves (underfed).

pH your water: Target pH 6.2–6.8 for soil grows. Every watering. This single habit prevents the majority of nutrient lockout issues that plague beginner grows. Cheap pH drops or a pH pen make this easy.

Training (optional for first grow): Low-stress training (LST) — gently bending and tying down the main stem — exposes lower branches to light and can significantly increase yield. It's not necessary for your first grow, but if you're comfortable, it's the single highest-impact technique for indoor plants.

Flowering Stage

Triggering flower (photoperiod plants): Switch your light schedule to 12 hours on / 12 hours off. This mimics shorter fall days and tells the plant to start producing buds. Autoflowers will enter flower on their own after 3–5 weeks regardless of light schedule.

Switch nutrients: Transition from vegetative nutrients (high nitrogen) to bloom nutrients (higher phosphorus and potassium). Most nutrient brands have a specific "bloom" formula. Continue starting at half strength.

Watch for males or hermaphrodites: If you're growing feminized seeds, this is unlikely but not impossible. Look for small pollen sacs (balls) at the branch nodes in the first 1–2 weeks of flower. If you see them, remove the plant immediately to prevent pollinating your females.

Environmental adjustments: Lower humidity to 40–50% during flower to prevent bud rot and mold. Maintain strong air circulation. Dense, resinous buds in stagnant, humid air is a recipe for mold.

Flowering takes 7–10 weeks depending on strain. Your plants will stretch (grow taller) during the first 2–3 weeks of flower, then shift all energy to bud production.

Harvest, Dry, and Cure

When to harvest: Don't trust your eyes at branch distance. Get a jeweler's loupe or USB microscope ($10–$15) and examine the trichomes (tiny mushroom-shaped crystals on the buds). When trichomes shift from clear to milky white with about 10–20% turning amber, it's harvest time. Clear trichomes = too early. All amber = overripe and more sedating.

Cutting: Cut the whole plant at the base or cut individual branches. Remove large fan leaves (the big ones with stems) but leave the smaller sugar leaves close to the buds — you can trim those later.

Drying: Hang branches upside down in a dark room at 60–65°F and 55–65% humidity. Good air circulation but no fans blowing directly on the buds. Drying takes 7–14 days. Buds are ready for the next step when small stems snap (not bend) when you flex them.

Curing: Trim buds from stems and place them in glass mason jars, filled about 75% full. For the first two weeks, open the jars for 15 minutes once or twice daily ("burping") to release moisture and refresh the air. After two weeks, reduce to burping every few days. Cure for a minimum of 2 weeks — 4–8 weeks produces noticeably better flavor and smoother smoke.