Iceberg is the head lettuce, and it plays by different rules from romaine. There is no cut-and-come-again option: each plant gives you one head, and the whole skill is judging the single moment when that head is firm, full and crisp — not too loose, not too tight, and not left so long that it bolts or rots. Picked right, an iceberg head is wonderfully crunchy and keeps longer in the fridge than any other lettuce.
Iceberg lettuce takes 70–85 days to mature, according to the Garden Grove crop data — a little longer than romaine. It is a hardy vegetable in the Asteraceae family with moderate water needs, so it grows best in cool weather and is happiest in spring and autumn. Heat is its enemy: iceberg bolts quickly when temperatures rise, and a bolted head is bitter and useless. For the full growing picture, see our growing guide for iceberg lettuce, and use the Harvest Date Calculator to work out your picking window from your sowing date.
Iceberg lettuce at a glance
| Growing factor | What iceberg lettuce needs |
|---|---|
| Days to maturity | 70–85 |
| Category | vegetable |
| Family | Asteraceae |
| Cold tolerance | hardy |
| Water needs | moderate |
Signs an iceberg head is ready to pick
Firmness is the test that matters. Cup the head gently in both hands and squeeze it lightly from the sides. A ready head feels firm and solid, like a well-packed ball, with a satisfying resistance when you press it. A head that feels soft, spongy or loose is not ready yet — the inner leaves are still filling out. A head that feels rock hard and is starting to split at the edges may be over-mature, so pick it immediately.
Size and shape back up the squeeze test. A mature iceberg head is round and full, roughly the size of a small melon, with the outer wrapper leaves a fresh green and the head itself pale green to white underneath. The outer leaves should be healthy and flat against the head, not yellowing or flopping open. If the head is still small and the leaves are loose and upright, give it more time.
The warning sign is bolting. When iceberg starts to bolt, the centre of the head pushes upward into a cone shape and the head loosens. Leaves may taste bitter even before the stalk is visible. Once you see the head starting to elongate or cone, pick it at once — it will not improve, and every warm day makes it more bitter. Unlike romaine, which you can keep leaf-picking, iceberg gives you no second chance: see our guide to when to harvest romaine lettuce for the leaf-picking alternative.
How to pick iceberg without damaging the crop
Cut the head at its base with a clean, sharp knife, about an inch above the soil, in one clean stroke. Do not pull or twist the head out of the ground: pulling tears the roots, disturbs neighbouring plants and leaves a ragged stump. A clean cut is also better for the soil, because the roots left behind break down and feed the soil.
Trim the outer wrapper leaves in the garden if they are damaged or dirty, but leave a couple of sound outer leaves on the head — they protect the tender inner leaves during handling and storage. Pick the head into a basket or a clean bag and keep it out of the sun. Handle heads gently: a bruised head browns at the bruise and rots there first.
One practical note: check each head for slugs and insects hiding between the outer leaves before you bring it indoors. A quick peel of the outermost leaf in the garden saves an unpleasant surprise in the kitchen.
The best time of day to harvest
Pick iceberg in the morning, when the heads are cool, crisp and full of water from the night. Morning-picked heads are at their crunchiest and they store far better than heads cut in the afternoon, when the plant has lost moisture and the leaves are softer and warmer.
If you must pick later, get the heads into the fridge as soon as possible, or plunge the cut head into cold water briefly to cool it down. Avoid picking when the leaves are wet from rain if you can, because wet heads rot faster in storage — and never leave cut heads sitting in the sun while you finish other garden jobs.
How often to pick
Iceberg is a one-cut crop, so "how often" really means "how often should heads be coming ready". The answer is: stagger your sowing. Sow a small batch every two to three weeks through the cool season so that a few heads mature each week, instead of twenty heads all on the same day. Each head should be cut the moment it is firm — leaving a ready head standing is the most common mistake in iceberg growing, because it is the head most likely to bolt, split or rot.
Because iceberg is hardy, a light frost will not ruin the crop, but a hard freeze will damage the heads, and summer heat will bolt them. Watch the weather forecast as heads approach maturity and bring the harvest forward if a heatwave or a hard frost is coming. See Zone 6 iceberg lettuce for an example of seasonal timing, and check your local extension service for sowing and harvest dates in your area.
What happens if iceberg is left too long
An iceberg head left too long does three bad things. First, it bolts: the centre stalk grows, the head loosens and cones upward, and the leaves turn bitter. Second, it can split: a mature head that takes up a lot of water after a dry spell, or after heavy rain, can crack open at the top. Third, it rots: the outer leaves lie on damp soil, the base softens, and rot works its way into the head.
None of these is fixable. A split or rotted head should be composted, and a bolted head is only fit for the compost heap or for seed saving if you let one plant flower deliberately. The lesson is simple: when a head feels firm, cut it.
How to store iceberg
Short term, iceberg is the longest-keeping lettuce there is, which is one of its great virtues. Store the head whole and unwashed in the refrigerator, in a loosely closed bag or container, and it will stay crisp for two weeks or more. The outer wrapper leaves protect the inner leaves, so do not strip them off until you are ready to use the head. Wash only the leaves you are about to eat.
Once cut, iceberg keeps less well: cut leaves go limp and brown at the edges within a day or two, even in the fridge. If you have cut more than you need, store the cut leaves in a container lined with a dry cloth and use them as soon as possible. Do not freeze lettuce — it turns to mush on thawing. If you have a glut of heads all ready at once, share them, or use them in cooked dishes: iceberg is good wilted into soups and stir-fries, where a head that is past its best raw is perfectly acceptable.
If you grow a lot of salad crops and want to plan quantities better, the Vegetable Yield Estimator can help you work out how many plants to sow next season.
Succession and continuous harvest tips
Because each plant gives one head, succession sowing is the whole strategy for a continuous iceberg supply. Sow little and often — a short row every two to three weeks — rather than one big sowing. In warm climates, grow iceberg in autumn, winter and early spring; in cooler climates, spring and late summer sowings give autumn heads.
Give plants a little afternoon shade in warm weather to slow bolting, and keep the soil evenly moist with mulch. A dry spell followed by heavy watering is what causes heads to split, so steady watering matters more than heavy watering. Thin seedlings to the spacing the plants need: crowded plants never form proper heads, and a head that cannot fill out properly will never pass the squeeze test. Browse the full guides hub for more harvest timing advice, and check your local extension service for the best sowing windows in your climate.
Frequently asked questions
When is iceberg lettuce ready to pick?
When the head feels firm and solid when you squeeze it gently, is round and full, and the outer leaves are fresh and green. Maturity is typically 70–85 days from sowing.
How do I know if an iceberg head is too loose?
Squeeze it: a ready head resists pressure and feels densely packed. A soft, spongy or loose head is still filling out — leave it for a few more days and test again.
Can you pick iceberg leaves like romaine?
No — iceberg is a head lettuce, not a leaf lettuce. Picking outer leaves does not give you a cut-and-come-again crop; it just damages the head. Each plant gives one head, cut whole.
Why did my iceberg bolt?
Heat, long days and dry soil all push iceberg to bolt. Grow it in the cool season, keep the soil evenly moist, give a little afternoon shade, and pick heads as soon as they are firm.
How long does iceberg last in the fridge?
Stored whole and unwashed in a loosely closed bag, an iceberg head stays crisp for two weeks or more — longer than any other lettuce. Check your local extension service for storage advice suited to your climate.