Vegetable · Asteraceae
Lettuce
Lactuca sativa
Kept cool, moist, and growing fast, lettuce turns a sunny sill or a corner bed into fresh salads in about a month.
Full sun
Every 2–3 days
55–64°F · 13–18°C
45–75 days
Overview
Few crops slip into a home the way lettuce does, moving from seed to salad in as little as 45 days and rewarding the smallest patch of light. It belongs to the daisy family and lives as a cool-season annual, at its best in the softer weeks of spring and fall when the kitchen wants something fresh. A raised bed by the back door, a corner box on the patio, or a single pot on a bright sill all suit it, and each one earns its keep.
The choice of type sets the mood of the harvest. Loose-leaf rosettes make a casual, pick-as-you-go supply for weeknight bowls, while upright romaines and soft butterheads read as tidier and more composed on the counter. Whichever fits your table, the plant keeps to a modest footprint and rarely climbs past 12 inches (30 cm), so it never crowds a small space or a busy sill.
The rhythm of the crop suits a cool-weather routine and resists a hot one. Left in a hot, dry summer it sends up a flower stalk and turns bitter almost overnight, which is no way to end a season. Grow it through cool weather with steady moisture and good light, and the leaves stay sweet and crisp from the sill or the bed straight to the plate.
Care
The short version: a sunny spot with a little afternoon shade in the heat, soil kept evenly moist, rich 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 on the table.
Light
Lettuce takes to full sun in cool weather, yet it settles happily into partial shade and even welcomes it as the days warm. A spot that catches morning sun and slips into afternoon shade keeps the leaves tender and eases the plant away from an early bolt.
Water
Keep the soil evenly moist at all times, watering every 2 to 3 days and deeper when the heat sets in. The roots sit shallow, so a dry spell puts the plant under stress quickly and turns the leaves bitter. Water deeply to about 6 inches and never leave the bed to dry out.
Soil
Give it loamy, rich, well-drained ground with plenty of organic matter worked through. A pH between 6.0 and 6.7 suits it well, and a bed that holds moisture without turning soggy delivers the steadiest, most reliable growth.
Temperature
This is a cool-season crop at its finest between 55°F and 64°F (13°C to 18°C). Once it edges past about 75°F it bolts, so plan the sowings for the mild shoulders of the year.
Humidity
Everyday outdoor humidity is more than enough, so there is no figure to chase. Steady soil moisture counts for far more than the air, since dry roots are what turn the leaves bitter.
Feeding
Work in a 5-10-10 fertilizer before planting, then sidedress once with calcium nitrate as the plants grow. That second feeding encourages leafy growth and quietly guards against the calcium shortfall behind tipburn.
Pruning
There is no real pruning to see to. Take the outer leaves as you go and the plant keeps giving, then lift it once it bolts, since the leaves only turn bitter from that point on.
Size & spacing
Lettuce keeps a tidy scale at 6 to 12 inches (15 to 30 cm) tall and roughly as wide. Allow each plant 6 to 12 inches (15 to 30 cm) of room so the leaves can round out and air can drift freely between them.
When to plant
Lettuce keeps a cool-weather calendar that fits neatly around the softer ends of the year. Start the first sowing in early spring once the soil can be worked, sow again in late summer for a fall supply, and let the hottest stretch pass, since the plants have no interest in the table then.
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
Nearly every lettuce hiccup shows on the leaves, and almost all of it traces back to heat, uneven water, or a hungry pest. Notice the early signs and a light touch usually keeps the crop looking its best. Find the match below, then act before the whole bed loses its polish.
A tall stalk rises at the center and the leaves lose their charm
This is bolting, the moment a plant leaves salad behind for seed once heat above 75°F (24°C) and longer days signal that its season on the table is closing. The leaves start to weep a milky sap and their sweetness slips away for good. Bring the harvest in the moment the center rises, drape the bed in afternoon shade through a hot spell, and lean on slow-to-bolt varieties to keep the pretty crop coming.
Fix:
- Harvest promptly before the plant fully bolts
- Switch to heat-tolerant, bolt-resistant cultivars
- Provide afternoon shade during hot spells
Curled leaves and a sticky film dull the crop
This is the mark of aphids, small soft-bodied insects that settle on the undersides of leaves and leave a sticky honeydew in their wake. Their feeding curls and distorts the fresh growth that should look its best. A firm jet of water sends them off, insecticidal soap handles the holdouts, and a resident crew of ladybugs and other predators keeps the planting looking clean.
Fix:
- Dislodge with a strong spray of water
- Apply insecticidal soap
Scorched edges spoil the look of the inner leaves
This is tipburn, a calcium shortfall in the racing heart of the plant rather than the work of any pest. When warm weather and uneven watering hurry the growth along, the inner leaves cannot draw in enough calcium and their edges brown at just the wrong moment for a handsome head. Keep the soil evenly moist and hold back on nitrogen so the growth never gets ahead of what the roots can serve up.
Fix:
- Maintain even soil moisture
- Avoid excessive nitrogen that pushes rapid growth
Ragged holes and slick trails mar the bed overnight
This is the calling card of slugs and snails, which dine after dark and leave glistening mucus trails that show up worst in damp weather. A scattering of iron phosphate bait, a torchlit round of hand-picking, and a clearing of the moist mulch and debris they shelter in soon settles them. Watering in the morning leaves the bed dry by nightfall, exactly the dry welcome they dislike.
Fix:
- Apply iron phosphate bait
- Hand-pick at night
- Reduce damp mulch and debris near plants
Toxicity
Lettuce is one of the most at-home plants you can grow. Every part is non-toxic to people and to cats, dogs, rabbits, horses, livestock, and birds, which is why it settles so easily into kitchens and hutches alike. Its one small footnote is the milky sap, which can leave a mild rash on very sensitive skin and nothing more.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Around cats, lettuce sits easy in the home, and a nibbled leaf does no harm. Most cats pass it by, though a curious one is welcome to help itself.
Dogs None
Lettuce belongs in a dog-friendly kitchen without a second thought. A generous helping can loosen the stool, so plain washed leaves in small amounts keep things graceful.
Horses None
Horses take to lettuce well as an occasional treat from the garden. Tear it into pieces and keep the portion modest, the same courtesy you would give any fresh green.
Rabbits None
Rabbits favor the crisp darker leaves, which suit them far better than the pale, watery hearts. Serve it washed and alongside their everyday hay for an easy treat.
Livestock None
Goats, sheep, and backyard stock can graze lettuce with complete ease. Even bolted plants going to seed remain fine, if a touch less tempting once the leaves turn bitter.
Birds None
Chickens and pet birds peck contentedly at fresh lettuce leaves with nothing to worry over. The darker, leafier kinds give them more to enjoy than the watery crispheads.
People None
Lettuce is a salad staple enjoyed raw or cooked and safe for everyone at the table. The milky sap may leave a mild rash on very sensitive skin, and that is the whole 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 select few earn a place at the table season after season. These are the ones worth keeping on the shortlist.
Parris Island Cos
A classic upright romaine of tall, crisp green leaves that carries good resistance to disease.
Tom Thumb
A petite butterhead that forms a neat single-serving head in about 70 days.
Simpson Elite
A fast-growing green leaf type that stands against bolting longer than most of its kind.
Red Sails
A bronze-red loose-leaf variety prized for its color and its slow, unhurried turn to bolting.
Defender
A romaine bred to shrug off downy mildew and the other diseases that trouble the crop.
How to propagate
Lettuce is about as forgiving as growing gets, and a single packet of seed keeps a kitchen in salad for months when it is sown in unhurried waves.
SeedEasy
Spring and late summer; sow in succession every 2-3 weeks for a continuous harvest · 7-14 days to germinate
Lettuce comes along beautifully from seed, whether scattered straight into the bed or raised as transplants on a bright indoor shelf. Sow it shallow, about a quarter inch deep, since the seed leans on light and cool soil to stir, and it rises in 7 to 14 days. Set a fresh pinch every 2 to 3 weeks through spring and once more in late summer, and the kitchen keeps a steady supply of leaves for months rather than one crowded glut.
Myths
Bitter lettuce is spoiled or rotten.
Bitterness is simply the plant's natural response to heat as it bolts, not a sign of rot. The leaves stay safe to eat, only less inviting on the plate. Keep the crop cool and gather it early and the sweetness holds.
Lettuce needs full hot sun all day to grow well.
It is a cool-season crop, and unbroken all-day sun only hurries it toward bolting. A little afternoon shade in the heat keeps it tender, though it still wants generous light for the rest of the day.