How Deep to Plant Lettuce Seeds (Hint: Barely Cover Them)
Lettuce might be the easiest vegetable to grow, but it's also one of the easiest to plant wrong. The mistake I see constantly? People treat lettuce seeds like bean seeds — pushing them down half an inch into the soil and covering them up. That's exactly wrong for lettuce.
Lettuce seeds should be planted no more than 1/8 inch deep. In fact, many experienced growers don't bury them at all — they press seeds onto a moist soil surface, mist them, and let them germinate right there. The reason is straightforward: lettuce is one of the few common vegetable seeds that actually requires light to trigger germination.
Planting depth and spacing by lettuce type
| Lettuce Type | Seed Depth | Thin/Space To | Row Spacing | Days to Germinate | Days to Harvest |
|---|---|---|---|---|---|
| Loose-leaf (e.g., Red Sails, Black Seeded Simpson) | Surface to 1/8 inch | 4-6 inches | 12 inches | 4-8 days | 40-50 days |
| Butterhead/Bibb (e.g., Buttercrunch, Tom Thumb) | Surface to 1/8 inch | 6-8 inches | 12-15 inches | 4-8 days | 50-65 days |
| Romaine (e.g., Parris Island, Jericho) | Surface to 1/8 inch | 8-10 inches | 15-18 inches | 5-10 days | 60-75 days |
| Crisphead/Iceberg (e.g., Great Lakes) | Surface to 1/8 inch | 10-12 inches | 18 inches | 5-10 days | 70-85 days |
| Mesclun Mix | Surface to 1/8 inch | 1-2 inches (dense) | 6-8 inches | 4-7 days | 25-35 days (baby) |
The light requirement explained
Most vegetable seeds are indifferent to light — they'll germinate whether it's dark or bright. But lettuce has a photoreceptor system (involving a pigment called phytochrome) that detects red light filtering through a thin layer of soil. When seeds sense that light, they know they're close enough to the surface to successfully emerge.
Bury them too deep and they don't get the light signal. The seed sits there, perfectly viable, waiting for conditions that will never come. Eventually it either rots or goes dormant. This is why people sometimes till or turn soil and get a sudden flush of lettuce — old seeds that finally made it close enough to the surface.
How to plant lettuce seeds (my method)
- Prepare a smooth, fine seedbed. Rake the soil surface until it's crumb-like and flat. Remove clumps and debris.
- Water the soil thoroughly first. Let it drain for 30 minutes so it's moist but not puddled.
- Sprinkle seeds thinly over the surface or in shallow rows. Because lettuce seeds are small, I mix them with a tablespoon of dry sand. This helps distribute them more evenly and you can see where you've already sown.
- Press seeds in gently with a flat board or the palm of your hand. Good soil contact matters for moisture uptake.
- Lightly dust with fine vermiculite — a barely-there layer, 1/16 to 1/8 inch. This keeps moisture around the seeds without blocking light.
- Mist daily until germination. Morning misting is best — gives the surface time to dry slightly before nightfall, reducing disease risk.
The heat problem: thermodormancy
Lettuce has another quirk that trips people up: when soil temperature exceeds about 80°F (27°C), the seeds enter dormancy and refuse to germinate. This is called thermodormancy, and it's the main reason people fail with summer lettuce plantings.
If you're planting in summer, you've got a few options:
- Pre-germinate in the fridge. Wet a paper towel, spread seeds on it, fold, put in a sealed bag, and refrigerate for 2-3 days. Plant the sprouted seeds immediately.
- Plant in shade. Afternoon shade from taller crops (tomatoes work great) keeps soil cooler. This is a natural companion planting strategy — see our companion planting chart for more combinations.
- Choose heat-tolerant varieties. Jericho (romaine), Muir (butterhead), and New Red Fire (loose-leaf) handle heat better than most.
- Plant in evening. Soil temperatures are lower and seeds get a cool night before the next day's heat.
Succession planting for continuous harvest
Lettuce matures quickly and bolts (goes to seed) when days get long and hot. Instead of planting a huge batch once, plant small amounts every 2-3 weeks from early spring through late spring, then again from late summer through fall.
A typical succession schedule for Zone 6 might look like this: first sowing 4 weeks before last frost, then every 2 weeks through May, skip June-July (too hot), resume in August for fall harvest. Our planting calendar can give you specific dates for your zone.
Starting lettuce indoors
Lettuce transplants well, so starting indoors is a perfectly good option — especially for early spring when outdoor soil is still cold and wet. Start seeds 4-6 weeks before your planned transplant date.
The same shallow depth rule applies: press seeds onto the surface of moist seed-starting mix and barely cover. Place under grow lights (or on a bright windowsill) since they need light from the very start. No heat mat needed — room temperature is actually ideal for lettuce.
Transplant seedlings when they have 3-4 true leaves, usually at 3-4 weeks old. Harden them off for a few days first. For more on timing seed starts, check our seed starting timeline for beginners.
Lettuce in containers
Lettuce is one of the best vegetables for containers. It has shallow roots (top 6 inches of soil), doesn't need much space, and looks attractive. Use any container at least 6 inches deep, fill with quality potting mix, and follow the same surface-sowing technique. Loose-leaf and mesclun mixes are especially well-suited to container growing.
For the full picture of planning your vegetable garden, including lettuce, take a look at our garden planning guide.
🥬 Get your lettuce planting dates
Our free planting calendar shows the best times to plant lettuce for both spring and fall harvests in your area.
Frequently asked questions
How deep do you plant lettuce seeds?
Plant lettuce seeds no more than 1/8 inch deep, or simply press them into the soil surface and mist. Lettuce seeds need light to germinate — burying them too deep prevents sprouting.
Do lettuce seeds need light to germinate?
Yes! Unlike most vegetable seeds, lettuce requires light exposure for germination. Plant them on or very near the surface.
What temperature do lettuce seeds need to germinate?
55-65°F is ideal. Above 80°F, lettuce seeds enter heat-induced dormancy (thermodormancy) and won't sprout at all.
Can you start lettuce seeds indoors?
Yes, and it works well. Start seeds 4-6 weeks before your last frost in cell trays under lights. Transplant at 3-4 weeks old.