Vegetable · Asteraceae
Lettuce
Lactuca sativa
Give it cool air, steady water, and quick growth, and lettuce rewards you with crisp salads in barely a month.
Full sun
Every 2–3 days
55–64°F · 13–18°C
45–75 days
Overview
If this is your first vegetable, lettuce is a kind place to begin, since it moves from seed to salad in as little as 45 days and forgives a beginner's stumbles. It belongs to the daisy family and grows as a cool-season annual, most content in the mild stretches of spring and fall. Tuck it into a backyard bed, a raised box, or a pot on a bright sill, and it will ask very little of you.
The types range from open rosettes of loose leaves to tall upright romaines and soft, folded butterheads, so there is one to suit however you like to harvest. Loose-leaf kinds let you take a few outer leaves at a time and come back for more, while heading types round out into a single cut. Whichever you pick, the plant stays small and rarely tops 12 inches (30 cm), so even a little space is enough.
The one thing lettuce truly minds is heat, and even that is easy to work around. Push it into a hot, dry summer and it will send up a flower stalk and turn bitter, but that is recoverable and never your fault. Offer cool weather, steady moisture, and good light, and the leaves stay sweet and crisp right up to the moment you cut them.
Care
The short version: full sun with a little afternoon shade once it warms, soil held evenly moist, rich and well-drained ground near a pH of 6.0 to 6.7, and cool weather between 55°F and 64°F (13°C to 18°C) so the leaves stay sweet.
Light
Lettuce loves full sun in cool weather, yet it takes partial shade in stride and even welcomes it once the days heat up. A spot with morning sun and afternoon shade keeps the leaves tender and eases the plant away from bolting, so you have room to relax.
Water
Try to keep the soil evenly moist at all times, watering every 2 to 3 days and a little deeper when it turns warm. The roots sit shallow, so a dry spell stresses the plant quickly and turns the leaves bitter. Water deeply to about 6 inches and simply do not let the bed run dry.
Soil
Settle it into loamy, rich, well-drained ground with plenty of organic matter mixed through. A pH between 6.0 and 6.7 suits it kindly, and soil that stays moist without turning soggy gives you the steadiest, most reassuring growth.
Temperature
This is a cool-season crop that feels its best between 55°F and 64°F (13°C to 18°C). Once it climbs past about 75°F the plant bolts, so lean your sowings toward the mild shoulders of the year and you will do fine.
Humidity
Everyday outdoor humidity is plenty, so there is no number to worry over. Steady soil moisture matters far more than the air, since it is dry roots, not dry air, that turn the leaves bitter.
Feeding
Mix in a 5-10-10 fertilizer before planting, then sidedress just once with calcium nitrate as the plants grow. That second feed encourages leafy growth and quietly guards against the calcium shortfall behind tipburn.
Pruning
There is no real pruning to fuss over. Pick the outer leaves as you go and the plant keeps giving, then pull it once it bolts, since the leaves only turn bitter from that point on.
Size & spacing
Lettuce stays comfortably compact at 6 to 12 inches (15 to 30 cm) tall and about as wide. Give each plant 6 to 12 inches (15 to 30 cm) of room so the leaves can fill out and fresh air can move between them.
When to plant
Lettuce is made for the cool ends of the year rather than high summer, and that makes the timing forgiving. Sow your first round in early spring the moment the soil can be worked, sow again in late summer for a fall crop, and simply let the hottest weeks pass, since the plants only want to bolt then anyway.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: 4-6 weeks before the last spring frost
- Plant: 2-4 weeks before the last spring frost; sow again in late summer for a fall crop
- Harvest: Spring and fall harvest (cool season)
Hardiness
USDA hardiness zones: 2–11
Temperature: down to -46°C
Troubleshooting
Almost every lettuce hiccup shows up on the leaves, and nearly all of it comes back to heat, uneven water, or a hungry pest, so you are rarely guessing. Spot the early signs and a quick, gentle fix usually saves the crop. Find what matches below, then act before the whole planting follows.
The center rises into a stalk and the leaves lose their sweetness
Take heart, this is just bolting, the natural moment a plant trades leaf-making for seed-making once heat above 75°F (24°C) and longer days signal that its cool season is closing. The leaves start to weep a milky sap and their sweetness slips away, but you have not done anything wrong. Cut as soon as the middle lifts, offer a bit of afternoon shade when it turns hot, and reach for slow-to-bolt varieties next round.
Fix:
- Harvest promptly before the plant fully bolts
- Switch to heat-tolerant, bolt-resistant cultivars
- Provide afternoon shade during hot spells
Puckered leaves with a sticky coating below
Do not worry, this is aphids, little soft-bodied insects that gather under the leaves and leave a sticky honeydew as they go. Their feeding puckers the fresh growth, but the plant recovers well once they are gone. Rinse them off with a firm jet of water, reach for insecticidal soap if a few cling on, and let ladybugs and their fellow predators finish the job for you.
Fix:
- Dislodge with a strong spray of water
- Apply insecticidal soap
Browned, scorched rims on the leaves tucked inside
Those browned edges are tipburn, and the good news is that no bug is behind it, just a little calcium falling short in the fast-growing heart. When warm weather and swings in watering hurry the plant along, the inner leaves cannot draw enough calcium and their rims give out. Keep the soil evenly moist and go gentle with nitrogen, and the growth will stay in step with what the roots can feed it.
Fix:
- Maintain even soil moisture
- Avoid excessive nitrogen that pushes rapid growth
Torn holes in the leaves trailed by a shiny film
This one is slugs and snails, gentle to fix even if it looks messy, and they do their chewing after dark, giving themselves away with glistening trails that show up worst in damp spells. Scatter a little iron phosphate bait, gather them by torchlight, and tidy away the moist mulch and debris where they hide. Watering early leaves the bed dry come nightfall, which they will happily avoid.
Fix:
- Apply iron phosphate bait
- Hand-pick at night
- Reduce damp mulch and debris near plants
Toxicity
Lettuce is one of the most reassuring plants you can grow. Every part is non-toxic to people and to cats, dogs, rabbits, horses, livestock, and birds alike, which is why it lands in so many bowls and hutches. Its only quirk is the milky sap, which may leave a mild rash on very sensitive skin and nothing beyond that.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
You can relax around cats, since a nibbled leaf of lettuce does them no harm at all. Most will pass it by, but a curious one is welcome to chew away.
Dogs None
Dogs are perfectly fine with lettuce, so there is nothing to fret over. A large helping might soften the stool a touch, so a few plain washed leaves keep things gentle.
Horses None
Horses take lettuce happily as a now-and-then treat with no cause for concern. Tear it into pieces and keep the portion modest, just as you would any fresh green.
Rabbits None
Rabbits love the crisp darker leaves, which sit far better with them than the pale, watery hearts. Rinse it well and serve it beside their everyday hay and they will thrive.
Livestock None
Goats, sheep, and backyard stock can graze lettuce with complete safety. Even bolted plants going to seed are fine, only a little less tempting once the leaves turn bitter.
Birds None
Chickens and pet birds peck away at fresh lettuce leaves without the slightest worry. The darker, leafier kinds give them more to relish than the watery crispheads do.
People None
Lettuce is a salad favorite eaten raw or cooked, and it is safe for everyone at the table. On very sensitive skin the milky sap can leave a mild rash, and that is truly the extent of it.
The milky sap may rarely cause mild contact dermatitis in sensitive individuals.
Varieties
Hundreds of lettuces fill the leaf, romaine, and butterhead camps, but a handful earn their spot season after season and make a friendly starting point. These are the ones worth getting to know by name.
Parris Island Cos
You can count on this classic upright romaine for tall, crisp green leaves and dependable resistance to disease.
Tom Thumb
A charming miniature butterhead, it rounds into a neat single-serving head in about 70 days.
Simpson Elite
A fast-growing green leaf type, it holds off bolting longer than most and forgives a warm spell.
Red Sails
This bronze-red loose-leaf favorite wins hearts for its color and its slow, patient walk toward bolting.
Defender
A reassuring romaine, it was bred to shake off downy mildew and the other common diseases.
How to propagate
Lettuce is about as forgiving as growing gets, and a single packet of seed will keep a salad bed going for months as long as you sow it in gentle waves.
SeedEasy
Spring and late summer; sow in succession every 2-3 weeks for a continuous harvest · 7-14 days to germinate
You will find lettuce wonderfully forgiving to start from seed, whether you scatter it right into the bed or coax a few transplants along indoors. Sow it shallow, about a quarter inch deep, because the seed leans on light and cool soil to stir awake, and it comes up in 7 to 14 days. Drop a fresh pinch every 2 to 3 weeks through spring and once more in late summer, and you will be cutting salads for months rather than all in one rush.
Myths
Bitter lettuce has spoiled or gone rotten.
Rest easy, because bitterness is simply the plant's normal reply to heat as it bolts, not a sign of rot at all. The leaves stay perfectly safe, only less pleasant on the tongue. Keep the crop cool and pick it early and the sweetness stays right where you want it.
Lettuce needs full hot sun all day long to do well.
Not so, since this is a cool-season crop and all-day blazing sun only hurries it into bolting. A touch of afternoon shade in the heat keeps it tender, while it still enjoys plenty of light through the rest of the day.