Most autoflowers grown indoors finish somewhere between 1 and 4 ounces of dried flower per plant. That range covers the honest middle. A first-time grower in a 3-gallon pot under a mid-tier LED often lands at 1 to 2 ounces, while someone who manages light, root space and training well pulls 4 to 6 ounces from the same seed pack. Eight ounces or more per plant happens, but it takes large containers, strong lighting, and a cultivar bred to get big.
What actually moves the number
Genetics set the ceiling
Autoflowering lines vary widely in size. Some stay short and finish in 65 days with a couple of dense colas. Others stretch past three feet and take 100 days. No amount of nutrients turns a small-bred auto into a heavy yielder. Buy from breeders who publish realistic per-plant figures rather than "up to 600 g/m²" marketing copy, and look for grow reports from people using setups similar to yours.
Root space limits everything above it
Autos start flowering on their own schedule, usually three to five weeks from sprout. If the roots hit the wall of a small pot before that, the plant flowers small and stays small. I treat 3 gallons as the floor for soil and 5 gallons as the sweet spot. Large auto cultivars do better in 7 gallons. Fabric pots help because they air-prune and dry more evenly than plastic.
cannabis yield per plant autoflower
Light is the biggest lever you own
Indoor autos run best on 18/6 or 20/4. Aim for a daily light integral around 30 to 45 mol/m²/day during flower, which works out to roughly 600 to 900 PPFD at the canopy for 18 hours. Yield climbs with light intensity up to a point, then flattens and eventually drops as leaves get stressed. A cheap PAR meter removes the guesswork. Keep the canopy 18 to 24 inches from a modern bar-style LED and raise the fixture as plants stretch.
Environment
Hold 75 to 80°F with lights on and 68 to 72°F at night. Humidity around 60 to 70% in veg and 40 to 50% in flower keeps transpiration steady. VPD between 0.8 and 1.2 kPa is a good target. Cold roots slow everything, so a heat mat or insulated floor helps in basements and garages.
Feed and water
Autos feed lighter than photoperiod plants, especially in the first three weeks. Start mild, watch the leaf tips, and build up. Overwatering is the most common early mistake and it stunts autos permanently because there is no time to recover. Let the top inch of soil dry between waterings.
Training
Low-stress training from week three onward opens the canopy and produces more even bud sites. Leaf tucking during stretch costs nothing. Topping works on vigorous plants if you do it by day 18 to 21, but it can set a slow auto back for a week it does not have. Light defoliation around day 40 helps airflow in dense plants.
Indoor vs outdoor yields
Outdoor autos planted after the last frost in a long US season often beat indoor plants on weight, because the sun is free and strong. Expect 2 to 8 ounces per plant outdoors, with the high end coming from big cultivars in the ground or in 10-gallon pots. The catch is weather. Cold nights in early spring and mold pressure in late summer cut into real harvests.
Yield per square foot and per watt
Four autos in a 4x4 tent at 3 ounces each is 12 ounces over 16 square feet, about 0.75 ounces per square foot. Somewhere between 0.5 and 1 ounce per square foot is a fair benchmark for autos. On electricity, 0.5 to 1 gram per watt of light is normal, and 1.25 g/W is a strong result.
Weigh it the same way every time
Dry weight is the only number that counts. Trim, hang at 60°F and 60% humidity for 7 to 10 days, then jar and cure until the buds hold 58 to 62% relative humidity. Weighing wet will inflate your result by 75% or more.
Why autoflower harvests come up short
- Pots too small for the cultivar
- Weak or too-distant lighting
- Overwatering in the first three weeks
- Transplant shock during a fixed veg window
- Topping too late
- Nutrient burn during early flower
- Chopping at cloudy trichomes instead of waiting for some amber
Chop timing is the quiet yield killer. Autos finish when they finish, and a plant pulled ten days early can lose a quarter of its weight while tasting like hay.