Most vegetables are grown from seed, but seed is only one way to make new plants. Some vegetables are easier — and more reliable — from cuttings, divisions, tubers, cloves or sets, and a few, such as garlic and potatoes, are hardly ever grown from seed at all. Knowing the right propagation method for each vegetable saves money, saves time, and gives you plants that are true to the variety you want, which matters when a seed-grown plant might not come true.
This guide covers the four main ways vegetables are propagated: seed, cuttings, division, and tubers, cloves and sets. It explains which vegetables suit each method, when to do it, and the mistakes that cause most failures. For timing and spacing, use our seed starting calculator and plant spacing calculator, and check your local extension service for the methods and dates that work best in your area.
Growing vegetables from seed
Seed is the method for most vegetables, and it is the cheapest way to grow a lot of plants. Lettuce, carrots, radishes, peas, beans, spinach and beets are usually sown direct, where they are to grow, because they dislike transplanting or because they are sown in such numbers that starting them in pots would be impractical. Tomatoes, peppers, eggplant, cucumbers and cabbage are usually started indoors and transplanted out, which gives them a head start and protects them from cold and slugs while they are small.
The rules for seed are simple and unforgiving. Sow at the right depth — as a guide, about twice the width of the seed — and no deeper, because small seeds sown too deep never reach the light. Keep the soil moist but not wet until germination, and do not let it dry out at the critical moment when the seed is sprouting. Give seedlings light as soon as they appear, or they will grow tall, pale and weak reaching for a window. Thin ruthlessly: a row of carrots left unthinned gives a row of tiny, useless roots, while a properly thinned row gives full-sized carrots. And use fresh seed — germination falls with age, and a packet that is several years old may give half the plants it should. Our guide to damping-off seedlings covers the disease that kills seedlings in cold, damp compost.
Cuttings: tomatoes, sweet potatoes and more
Some vegetables root readily from cuttings, and this is the fastest way to multiply a plant you already like. Tomatoes are the classic example: the side shoots, or suckers, that grow in the leaf joints can be snapped off and pushed into moist compost, where they root within a week or two and grow into a full plant, identical to the parent. This is useful late in the season, when you want a few extra plants, or when a variety you love is no longer available as seed. Sweet potatoes are propagated from slips — shoots grown from a tuber in water or damp compost, then snapped off and rooted. Peppers and eggplant can be grown from cuttings too, though they are slower to root than tomatoes.
To take a cutting, choose a healthy, non-flowering shoot about 10 to 15 centimetres long, cut just below a leaf joint, remove the lower leaves, and push it into moist, free-draining compost. Keep it humid — a clear plastic bag over the pot works well — and out of direct sun until roots form, then pot it on. Take cuttings in the morning, when the plant is full of water, and never take cuttings from a diseased plant, because the cutting carries the disease with it. If you are unsure whether a plant is healthy enough to propagate from, check your local extension service for advice on the symptoms you are seeing.
Division: rhubarb, asparagus, artichokes and chives
Division is splitting an established clump into pieces, each with roots and shoots, and replanting them. It is the method for perennial vegetables that come back year after year. Rhubarb is divided in autumn or early spring: dig up the crown, cut it into pieces with a sharp spade, making sure each piece has at least one strong bud, and replant in compost-rich soil. Asparagus crowns are divided rarely, but established beds can be split when they are dormant. Globe artichokes produce offsets — young shoots at the base — which can be cut away with roots attached and replanted. Chives and other clump-forming perennials are divided every few years, which also rejuvenates a tired clump.
Division is best done when the plant is dormant or just starting into growth, so the pieces establish before the growing season. Water the pieces well after replanting, and do not harvest from a newly divided rhubarb or asparagus plant in its first year — let it build up strength. Use a sharp, clean tool, and make clean cuts rather than tearing, because ragged wounds rot. Division is also the way to share plants: a single rhubarb crown can give you half a dozen new plants and several more for friends, all identical to the parent, which seed cannot guarantee.
Tubers, cloves, sets and crowns
Some vegetables are propagated from a piece of the plant itself, not from seed. Potatoes are grown from seed potatoes — small tubers, or pieces of tuber with at least one eye each — planted in spring. Garlic is grown from cloves: break a bulb into cloves in autumn, plant each clove pointed end up, and each one grows into a full bulb by summer. Onions can be grown from seed, but many gardeners grow them from sets — small, immature bulbs planted in spring — which is easier and more reliable. Jerusalem artichokes are grown from tubers, horseradish from root cuttings, and asparagus from one-year-old crowns planted in a prepared trench.
Buy certified seed potatoes and garlic, rather than using supermarket produce, because shop-bought tubers and bulbs can carry disease and may have been treated to stop them sprouting. Plant at the right depth — potatoes are planted deep and earthed up as they grow, garlic cloves are planted just below the surface — and in well-drained soil, because all of these will rot in wet ground. Our guide to root rot treatment explains what happens when drainage fails. If a crop grown from tubers or cloves does badly, check your local extension service — they can test for the soil-borne diseases that build up when the same crop is grown in the same bed too often.
Saving seed and keeping varieties true
Saving your own seed is satisfying and saves money, but it needs care. Open-pollinated varieties come true from seed, while F1 hybrids do not — seed saved from a hybrid gives plants that vary, and most of them will be worse than the parent. If you want to save seed, grow open-pollinated varieties, and let a few of the best plants go to seed: a lettuce left to flower, a bean left to dry on the plant, a tomato left to ripen fully. Dry the seed thoroughly, store it in a cool, dry, dark place in a labelled paper envelope, and use it within a year or two.
Cross-pollination is the trap. Squashes, pumpkins, cucumbers and sweetcorn cross readily with other varieties of the same species, so seed saved from a squash grown near other squashes may give you something quite different next year. Grow only one variety of each cross-pollinating crop if you plan to save its seed, or isolate the plants. Self-pollinating crops such as peas, beans and tomatoes are much safer for beginners. And label everything: seed that is not labelled is seed that will be sown in the wrong place at the wrong time.
Common mistakes
The most common propagation mistake is sowing seed too deep, or into cold, wet soil, and then blaming the seed when nothing appears. The second is transplanting crops that hate it — carrots, parsnips and radishes should always be sown direct, because transplanting forks and stunts their roots. The third is taking cuttings from a diseased plant and spreading the disease to a new bed. The fourth is dividing a plant at the wrong time — in the heat of summer, when the pieces dry out before they can root. And the fifth is using supermarket potatoes or garlic as planting material, which can introduce disease and may not sprout at all. Start with clean material, the right method, and the right timing, and propagation is one of the most reliable skills in the garden.
| Vegetable | Best method | Notes |
|---|---|---|
| Tomatoes, peppers, eggplant | Seed indoors, or cuttings | Side-shoot cuttings root in 1–2 weeks |
| Carrots, parsnips, radishes | Seed direct | Never transplant; roots fork if moved |
| Peas, beans | Seed direct | Sow where they are to grow |
| Potatoes | Seed potatoes (tubers) | Buy certified; plant in spring, earth up |
| Garlic | Cloves | Plant in autumn, pointed end up |
| Onions | Seed or sets | Sets are easier and more reliable |
| Rhubarb, artichokes | Division | Divide while dormant; let new plants establish |
| Sweet potatoes | Slips from a tuber | Root slips in water or compost, then plant out |
Frequently asked questions
Can you grow tomatoes from cuttings?
Yes — tomato side shoots root easily in moist compost within a week or two and grow into plants identical to the parent. It is a quick way to get extra plants late in the season, though seed-grown plants started early usually give a bigger harvest.
Should carrots be sown direct or transplanted?
Always sow carrots direct where they are to grow. Carrots, parsnips and radishes hate transplanting — moved seedlings grow forked, stunted roots. Sow thinly, keep the soil moist until germination, and thin to the spacing the packet recommends.
How do you propagate potatoes?
Potatoes are grown from seed potatoes — small tubers, or pieces of tuber with at least one eye each — planted in spring. Buy certified seed potatoes rather than using supermarket potatoes, which can carry disease and may have been treated to stop sprouting.
Can I save seed from my vegetables?
You can save seed from open-pollinated varieties, which come true, but not from F1 hybrids, which do not. Peas, beans and tomatoes are good beginner choices because they mostly self-pollinate; squashes and sweetcorn cross readily and need isolation.
When is the best time to divide rhubarb?
Divide rhubarb in autumn or early spring while it is dormant. Dig up the crown, cut it into pieces with a sharp spade so each piece has at least one strong bud, replant in compost-rich soil, and do not harvest from the new plants in their first year.