Autoflower started flowering while still small

Likely causes, most likely first

Ranked for this sign on its own. Your stage, medium and readings change the order, so run the checker for your plant.

1. PossibleAutoflower stunted by early stress

   EnvironmentDeal with it this weekRead: Why is my autoflower so small?

   Fix: Autos run on a countdown from germination, so lost growth never returns. Next run: sow straight into the final 11-19 L (3-5 gal) pot, never transplant, water seedlings in small rings, give 300-600+ µmol/m²/s early, train with LST only (topping never matches proper LST). This run: keep conditions steady and feed well; don't add more stress.

   Recovery: Steady weekly growth from here on; size gap to siblings stops widening.

   How to confirm it

   • Lift the pot and check moisture at depth. Lift the pot right after a full watering to learn its wet weight, then lift before each watering. Water when it is clearly lighter (about half the added water gone). Push a finger or a moisture probe 5 cm (2 in) down. Heavy for 3-4+ days with droop: overwatering. Very light with limp papery leaves: thirst.
   • Measure PPFD at the canopy top. Use a quantum (PAR) meter, or a calibrated phone app as a rough guide, at the top leaves in a 5-9 point grid. Compare with the stage target: seedlings 100-300, veg 300-700, flower 800-1,200 µmol/m²/s at ambient CO2. Bleaching and taco at the top above ~1,100 point to light; stretch below ~300 in veg points to too little.

2. PossibleOverwatering (roots short of air)

   Root zoneDeal with it this weekRead: Drooping cannabis: overwatering vs underwatering

   Fix: Water only when the pot is clearly lighter (about half the water used), then water to 10-20% runoff. Seedlings in big pots: water a small ring near the stem only. Add air: fabric pots, 25-40% perlite, no saucer standing water. Let a soaked pot dry back before the next watering.

   Recovery: Leaves lift within a day of drying back; colour and growth recover within 5-7 days.

   How to confirm it

   • Lift the pot and check moisture at depth. Lift the pot right after a full watering to learn its wet weight, then lift before each watering. Water when it is clearly lighter (about half the added water gone). Push a finger or a moisture probe 5 cm (2 in) down. Heavy for 3-4+ days with droop: overwatering. Very light with limp papery leaves: thirst.
   • Look at the roots. Hydro: lift the net pot and look at the root mass in good white light. Containers: tip the plant out with a hand over the medium and look at the edges and bottom of the root ball. Healthy roots are white to cream with fine fuzzy tips. Brown roots whose outer layer slides off between the fingers leave a bare thread: rot. Firm, evenly tan roots with white tips in coloured solution are staining.
   • Smell test of roots, medium and reservoir. Smell the roots, the bottom of the root ball, the drain water or the reservoir up close. Healthy roots smell earthy or of nothing. A sour, rotten, swampy or sewage smell means anaerobic conditions and rot. In hydro, a slimy feel on the reservoir walls or tubing adds to the case.

3. Less likelyRecovery stall after topping, supercropping or heavy defoliation

   Physical damageLow urgencyRead: How long does a plant take to recover after topping?

   Fix: Give 3-7 days for photoperiods to recover from topping or HST before the next session; don't stack stresses. Prefer tucking to stripping leaves. On autos use LST only.

   Recovery: New growth resumes within a week.

   How to confirm it

   • Watch new growth for 5-10 days after one change. Make one correction at a time, mark the top node with a twist tie and photograph the same leaves every 2-3 days. Damaged leaves never recover; judge only new growth and whether the symptom stops spreading. Mobile-nutrient symptoms stop climbing within 5-7 days; immobile ones show in new leaves within 7-10 days.

4. Less likelyTransplant shock

   Physical damageDeal with it this weekRead: Transplanting: when, into what, and avoiding transplant shock

   Fix: Move the root ball intact into pre-moistened medium of the same type and pH, water in with a mild solution, lower light 10-20% and keep RH slightly higher for 2-3 days. Mild droop for 2-5 days is normal; longer means root damage, waterlogging or a pH mismatch. Autos: sow in the final pot instead.

   Recovery: Turgor back in 1-3 days; new growth within a week.

   How to confirm it

   • Lift the pot and check moisture at depth. Lift the pot right after a full watering to learn its wet weight, then lift before each watering. Water when it is clearly lighter (about half the added water gone). Push a finger or a moisture probe 5 cm (2 in) down. Heavy for 3-4+ days with droop: overwatering. Very light with limp papery leaves: thirst.
   • Measure input pH and root-zone (runoff or reservoir) pH. Calibrate the meter with fresh pH 7 and pH 4 buffers, then measure the mixed feed and the runoff (containers) or reservoir (hydro). Soil and living soil should sit at 6.0-7.0, coco, rockwool and peat mixes at 5.5-6.5, hydro at 5.5-6.2. Track 3+ readings; one reading is not a trend.

Look for

Plant with its pot size and age in days since sprouting..