Lettuce is the easiest hydroponic plant on Earth. With the Kratky method you can grow a head of buttercrunch from seed to salad bowl in 28 days, with zero pumps and almost zero effort.
The shortest path: Kratky in a mason jar
If you're brand new, read our Kratky method primer first. The setup takes 15 minutes and costs about $15.
Best varieties
- Buttercrunch — sweet, soft, beginner-proof.
- Salanova — premium loose-leaf, gourmet results.
- Romaine "Little Gem" — crunchy, compact.
- Skip: Iceberg — it wants soil and cold nights.
Lighting
Lettuce only needs 12–14 hours of light per day. A bright window plus a supplemental LED is plenty. Too much light makes leaves bitter.
Temperature matters
Lettuce hates heat. Keep your grow space below 75°F or your lettuce will "bolt" (shoot up a flower stalk) and turn bitter. Most apartments are fine year-round.
Nutrients
Half-strength nutrients work great for lettuce — it's a light feeder. Top up the reservoir with plain pH-adjusted water as it drops; don't add more nutrients until you start a new cycle.
Harvest
Two options: pick outer leaves continuously starting at week 3, or cut the whole head at the base at week 4. The cut-and-come-again approach is more forgiving.
Stagger for continuous salad
Start one new seedling every 7 days. You'll have a constant rotation of fresh heads forever.
Frequently asked questions
Why are my lettuce leaves bitter?
Heat, too much light, or you let it bolt. Move it somewhere cooler and harvest earlier next time.
Can I regrow lettuce after cutting?
Sort of — you'll get a smaller second cutting, then it's done. Restart from seed every 4 weeks for a continuous supply.
Do I need to refrigerate before eating?
A 30-minute chill in the fridge makes hydroponic lettuce extra crisp, but you can eat it straight off the plant.
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