Saving Seeds from Your Best Vegetable Plants

Why Saving Your Own Seed Pays Off on a Small Plot

Saving seed is one of the quiet pleasures of growing your own. Once you have a few seasons behind you, the packet of seed on the shed shelf starts to feel like an unnecessary expense. A single healthy bean plant, left to ripen fully, can give you enough seed for years of sowings. Tomatoes, lettuce, peas, chard and chillies are all straightforward to save on an allotment or in a small back garden, and each generation you select on your own soil becomes slightly better adapted to it.

It is not just thrift. Choosing seed from the plants that cropped earliest, tasted best and shrugged off disease is real plant breeding, done at your own kitchen table. Do it properly and the results are genuinely worthwhile; do it carelessly and you will waste a year, so a little method matters.

Start with Open-Pollinated Plants Only

The single most important rule is to save seed from open-pollinated varieties, sometimes called heritage or standard varieties. These come true from seed, so next year's plants will resemble this year's parent.

• F1 hybrids are a dead end. Their offspring will be a mixed, unpredictable lot, often reverting to something stringy or bitter.
• Check the packet before you sow. If it says F1, enjoy the crop but buy fresh seed next year.
• Watch for crossing. Related plants can cross-pollinate and spoil your seed. Beans need roughly 100 metres of separation, brassicas far more, and courgettes, pumpkins and marrows all cross with each other freely.

On a small site, distances are impossible, so use barriers instead. Fine mesh bags or fleece cages over a single plant will keep bees and pollen out. Tomatoes, peas, French beans and lettuce are largely self-pollinating and need little fuss. Cucurbits and brassicas are the awkward ones: grow only one variety of each in a season if your plot is tight, or hand-pollinate a few flowers and tie them off with a paper bag.

Choose the Best Plants, Not the First Ones

Save from your strongest performers, never from the runts or the ones you left because they were too tough to eat. Walk the plot before harvest and mark your chosen plants with a bright string or cane. Then treat them as seed crops, not dinner.

Look for plants that germinated strongly, held their foliage well against mildew or blight, cropped heavily and tasted good raw. For salads, choose the ones that bolted last. For beans, pick plants that kept producing long after the rest had given up. Eat from all the others and leave your chosen few alone. One or two plants of most vegetables will yield far more seed than you can use, so share the surplus with plot neighbours.

Let the Seed Mature Fully

Seed must ripen on the plant, not on a windowsill. This is where most beginners go wrong, harvesting pods the moment they look dry rather than waiting for a proper finish.

• Peas and beans: leave the pods until they turn brown, papery and rattle when shaken. Pull the whole plant, hang it upside down in a shed or greenhouse over a sheet, and shell it out once brittle.
• Lettuce: let two or three plants bolt and flower. When the seed heads turn fluffy and white, shake them into a paper bag each evening.
• Tomatoes: scoop the gel and seed from a fully ripe fruit into a jar, add a little water and leave three to five days until a mould film forms. Rinse well, then dry.
• Peppers and chillies: leave the fruit on the plant until it colours fully, then scrape seed from the best-shaped one.
• Chard and spinach: seed ripens unevenly up the stalk, so collect in stages as each cluster browns.

Parsnips, carrots, onions and most brassicas are biennials, flowering in their second year. They need overwintering space and, for carrots, isolation from wild carrot, which makes them a poor choice on a crowded plot.

Dry, Clean and Label Properly

Spread seed in a single layer on a china plate or a sheet of paper, never in a thick pile, and leave it in a warm, airy room out of direct sun for a fortnight. It is dry enough when a seed snaps cleanly between your thumbnail rather than bending. Anything still leathery will go mouldy in store.

Clean as you go: rub pods between your palms, winnow the chaff away, and pick out any discoloured or shrivelled seed, which is usually the unviable fraction. Then label immediately, with the variety, the year and a note about why you chose that plant. A pencil on paper lasts; a fading biro does not.

Storing Seed So It Still Germinates in Three Years

Put the labelled envelopes in an airtight jar with a sachet of silica gel and keep it somewhere cool, dark and steady. A kitchen cupboard is too warm and a damp shed is worse. A cool bedroom drawer or the bottom of a fridge works well.

Kept this way, beans and peas will germinate for three or four years, tomatoes and brassicas for five, and lettuce for two or three. Onions and parsnips are the exception: their seed dies quickly, so save fresh each year. Test a few seeds on damp kitchen paper in spring if you are unsure, and sow a little thicker when in doubt. Before long, half the packets on your shelf will carry your own handwriting, and that is a shelf worth having.