Seed Saving for Beginners UK

Every tomato you grow holds enough seed for dozens of plants next year. Every bean pod left on the plant holds next year’s crop. If you grow open-pollinated varieties, you’re already growing your own seed. You just need to collect it.

Here’s how to save your own seed, starting with the easiest crops and building up to the trickier ones.

Why save your own seeds?

Saving seed keeps the varieties that do best in your soil and weather. Pick seed from your best plants each year, and bit by bit the variety suits your patch better.

It saves money too. One tomato can hold well over a hundred seeds, and a few bean pods give you enough for a row next year.

There’s more to it than money:

• Independence: you don’t have to rely on buying new packets each year
• Keeping old varieties going: many heritage varieties are no longer sold
• Choosing the best: save from your best plants and your stock gets better over time
• Connection: you’re doing what gardeners have done for generations
• Swapping: saved seed is the currency of gardening clubs and allotments everywhere

The Heritage Seed Library, run by Garden Organic, looks after hundreds of old and unusual varieties that you can’t buy in shops. Members get a selection of seed each year, and many of the varieties were kept going by ordinary gardeners for decades.

Open-pollinated vs F1 hybrids

Open-pollinated varieties grow into plants just like their parents. F1 hybrids don’t. This is the most important thing to understand about seed saving.

Open-pollinated (OP) varieties have been grown and selected for many generations. Save seed from an OP tomato and next year’s plants will be the same variety. Heritage, heirloom and traditional varieties are all open-pollinated.

F1 hybrids come from crossing two particular parent plants. The first generation is uniform and often vigorous. But seed saved from F1 plants grows into a muddle of the parents’ traits, and the results are unpredictable and usually disappointing.

Rule of thumb: if the packet says F1, don’t save seed from those plants. Look for open-pollinated, heritage or heirloom on the label.

The easiest crops to start with

Start with crops that pollinate themselves and need no special treatment. These four give you reliable seed with very little effort.

Tomatoes

Tomatoes are the best crop for a first go. Most varieties pollinate themselves, so crossing is rare even when different varieties grow side by side. Some heritage types, such as potato-leaved varieties, cross more easily, so give them a few metres of space. Our tomato growing guide covers growing them.

Choose your tastiest, healthiest plant. Pick a fully ripe fruit from the second or third truss. Cut it in half and squeeze the seeds and jelly into a glass jar.

Beans

Runner beans and French beans are easy. Leave the pods on the plant until they turn brown and papery and the seeds inside are hard. Pick the pods, shell the seeds and spread them on a plate to finish drying for a week. Our runner bean guide has growing tips.

Bees can cross runner beans, so grow just one variety if you want pure seed. French beans pollinate themselves and rarely cross, so they’re even simpler.

Leave bean pods on the plant until they’re brown and papery and the seeds rattle. Then shell them and dry the beans indoors for a week.

Peas

Peas pollinate themselves before the flower even opens, so they’re almost foolproof. Leave the pods on until they turn yellow and rattle when shaken. Pick them, shell them and dry the peas indoors for two weeks. Our pea growing guide has variety ideas.

Lettuce

Lettuce pollinates itself and makes lots of seed. Let one or two plants bolt (run to flower) in summer. When the fluffy little seed heads appear, cut the stems and shake them into a paper bag. Each plant gives you hundreds of seeds. Our lettuce growing guide has varieties that suit UK gardens.

Tomato seeds and jelly squeezed into a jar. Leave them for two or three days until a white mould appears on top.

The wet method

The wet method is for seeds that sit in juicy fruit, mainly tomatoes and cucumbers. The jelly round the seeds stops them sprouting, so it needs removing before you store them.

How to ferment tomato seeds

1. Squeeze the seeds and jelly from a ripe tomato into a clean glass jar
2. Add about the same amount of water
3. Cover loosely with a cloth or paper towel and leave at room temperature
4. Stir once a day. After two or three days, a white mould forms on top
5. Top up with water and give it a good stir. Good seeds sink to the bottom
6. Pour off the mould, pulp and floating seeds (the floaters are duds)
7. Rinse the good seeds in a fine sieve under the tap
8. Spread them on a ceramic plate or glass dish to dry. Not paper towel, as they stick to it
9. Dry at room temperature for a week or so, stirring daily so they don’t clump

Fermenting breaks down the jelly and can help reduce some diseases carried on the seed. It takes two or three days in warm weather, and up to five when it’s cooler. Don’t leave it longer than that, or the seeds may start sprouting in the jar.

Cucumber and melon seeds

The same method works for cucumbers, melons and their relatives. Let the fruit ripen fully on the plant (cucumbers go yellow and soft), scoop out the seeds and ferment as above. Insects cross these freely, so grow just one variety of each if you’re saving seed. Many greenhouse cucumbers are all-female F1 hybrids that fruit without pollination, so they rarely give useful seed.

How do you save chilli and pepper seeds?

Chilli and pepper seeds are saved dry, not fermented. Leave the fruit on the plant until it reaches its full ripe colour, usually red, orange or yellow. Green peppers aren’t ripe, and their seed often isn’t either.

Cut the fruit open and scrape the seeds onto a plate. Wear gloves for hot chillies, and keep your hands away from your eyes. Dry the seeds for one to two weeks until they snap cleanly. Peppers mostly pollinate themselves, but insects can cross varieties grown close together. For pure seed, grow one variety, or cover a few flowers with fine mesh or a paper bag before they open and mark the fruit that sets. As with tomatoes, skip F1 varieties.

Save chilli seed only from fully ripe, coloured fruit. Spread the seeds on a plate and dry them until they snap cleanly.

The dry method

The dry method is simpler and works for most garden crops, including beans, peas, onions, herbs and flowers. The seeds ripen in pods, capsules or seed heads that dry out on the plant.

The basics

• Let seeds ripen fully on the plant before you collect them
• Collect on a dry day, in the afternoon once the dew has gone
• Spread seeds on plates or trays in a warm, airy room to finish drying
• Give them two or three weeks indoors before packing them away
• Get rid of bits of husk by blowing gently across the seeds or shaking them through a colander

Crop by crop

Beans and peas: Leave the pods on until they’re completely dry and brown, and the seeds rattle. If wet autumn weather is coming, pull up the whole plant and hang it upside down in a shed to finish drying.

Lettuce: Cut the seed heads when the fluffy white tufts appear, like tiny dandelion clocks. Shake into a paper bag, then rub between your fingers over a sieve to separate seed from fluff.

Calendula and marigold: Wait until the seed heads are dry and brown, then pick the seeds by hand. They’re big and easy to handle. Calendula seeds look like little curled caterpillars.

Herbs (dill, coriander, fennel): Cut the seed heads when they turn brown but before they scatter. Pop them upside down in a paper bag to catch the seeds as they finish drying.

Dried seed heads ready to collect: calendula, nigella, lettuce and dill. Pick them on a dry afternoon.

Can you save seeds from shop-bought fruit and vegetables?

You can, but it’s a gamble. Most supermarket tomatoes, peppers, cucumbers and squashes are F1 hybrids, so their seed won’t come true. Squashes and pumpkins may also have crossed with other varieties in the field.

Some do better than others. Dried beans and peas sold for cooking, such as borlotti beans or marrowfat peas, often sprout and grow true, though germination can be patchy. Organic or heritage tomatoes from a farmers’ market are more likely to be open-pollinated. Treat any shop-bought seed as a fun experiment, and grow a known open-pollinated variety alongside it.

Can you save your own seed potatoes?

You can keep small potatoes from your own crop to replant, but there are risks. Saved potatoes can carry virus diseases and blight from one year to the next, and crops often get smaller after a year or two.

Seed potatoes sold in the UK are certified, grown where there are fewer of the aphids that spread viruses. For reliable crops, buy certified seed potatoes each spring. If you do save your own, use only tubers from healthy plants with no sign of blight, store them cool and frost-free, and never replant any with rot. The tiny seeds in potato berries don’t come true.

Drying and storing seeds

Seeds must be really dry before you store them. Damp seeds go mouldy, rot or die quickly. This is where most beginners slip up.

How to dry seeds

Spread seeds in a single layer on ceramic plates, glass dishes or fine mesh. Avoid paper towel (small seeds stick to it) and newspaper (the ink can rub off). Put them somewhere warm, dry and airy. An airing cupboard works well. A sunny windowsill gets too hot and can damage the seed.

Stir them once a day so they dry evenly. Most seeds are ready after one to two weeks at room temperature. To check, try to bend a bean. If it snaps cleanly rather than bending, it’s dry. For small seeds, press a fingernail into one. If it dents rather than cracks, give it longer.

The silica gel trick

Pop a small sachet of silica gel into your seed jars to soak up any leftover moisture. Save the ones that come in shoe boxes and vitamin bottles. Dry them out or replace them when they’re full. Drier seed lasts longer.

Where to keep them

Fridge and freezer storage only helps if the seed is fully dry and sealed. Let the jar warm up to room temperature before you open it, or condensation will dampen the seed. For most people, glass jars with tight lids in a cool, dark cupboard work brilliantly. Label every jar with the variety, the date and notes on the parent plant. Small jam jars in a cardboard box, somewhere that stays cool through winter, are ideal.

Labelled seed jars in a cool, dark cupboard. Note the variety, the date and anything special about the parent plant.

Checking your seed is still good

Test old seed before you rely on it. Even well-stored seed slowly loses its oomph, and some kinds fade faster than others.

The paper towel test

1. Count out 10 seeds
2. Dampen a sheet of kitchen paper (moist, not dripping)
3. Space the seeds out on one half
4. Fold the other half over the top
5. Pop it in a sealed plastic bag or food box
6. Keep it at room temperature for one to two weeks
7. Count how many have sprouted

What the results mean:

• 8-10 sprouted: great, sow as normal
• 5-7 sprouted: fine, sow about half as thickly again
• Fewer than 5: time for fresh seed

Ten seeds on damp kitchen paper tells you all you need to know. Most sprouting means the batch is good to sow as normal.

Roughly how long seeds keep

Parsnip and onion seed fade so quickly that saving them only makes sense if you’ll sow the next spring. Our seed sowing calendar shows the best time to sow all the common veg.

Building your own seed bank

A seed bank is simply an organised collection of your saved seed. Over a few years, you build up a store of varieties you know do well in your garden.

Getting started

Begin with three or four easy crops in your first year. Tomatoes, runner beans, lettuce and calendula make a great starter set. Save seed from your healthiest, most productive plants, label everything and store it somewhere cool and dark.

In year two, add peas, French beans and a couple of herbs. By year three, you’ll be buying far fewer seed packets.

Keeping notes

Good notes make all the difference. For each variety, jot down:

• Variety name: be precise, so “Gardener’s Delight”, not just “tomato”
• Year saved: on every jar
• Parent plant: was it the best cropper, the healthiest, the tastiest?
• Germination test: test each batch once a year and note the result
• Any problems: poor germination, odd-looking plants or disease

A notebook is fine, and some people use a spreadsheet. The main thing is to keep it up.

Seed swaps

Seed swaps are a much-loved tradition. Local gardening clubs, allotment societies and Garden Organic hold seed swap events where you can trade saved varieties with other growers.

Online groups and forums swap seed too. It’s where you’ll find varieties you can’t buy, often suited to particular regions.

Seed saving and the law

Saving seed from your own garden for your own use is legal in the UK. The rules that matter are about selling seed, not saving it.

Some varieties are protected by plant breeders’ rights under the Plant Varieties Act 1997. Section 8 of the Act says those rights don’t cover private, non-commercial use. So saving seed from a protected variety for your own garden is fine.

Selling seed is a different matter. Veg seed sold commercially must be from varieties on an official list and meet seed marketing rules. That’s why the Heritage Seed Library gives its unlisted varieties to members instead of selling them. Free swaps between gardeners are a long tradition. If you want to sell saved seed, check the current rules first, as open-pollinated varieties can be protected too.

Ready for a challenge?

Once you’re confident with the easy crops, you can try ones pollinated by insects or wind. These need a bit more care to keep varieties pure.

Keeping varieties apart

Crops that cross need distance between varieties so insects or wind can’t carry pollen between them.

In most gardens and allotments, that’s not practical. The easy answer is to grow just one variety of each, or use barriers like bags or mesh.

Hand pollination

For courgettes and squash, hand pollination gives you pure seed without any distance. Find a female flower (it has a tiny fruit behind the petals) the evening before it opens and tape it shut with masking tape. Next morning, pick a male flower of the same variety, peel back its petals and dab its pollen onto the centre of the female flower. Tape the female flower shut again. Tie a label round the stem so you know which fruit to save seed from.

Taping the female flower shut after you’ve dusted on pollen stops insects bringing in pollen from other varieties. Tag it so you know which fruit to keep.

Crops that take two years

Some veg need two seasons to make seed. Carrots, parsnips, beetroot, onions, leeks and the cabbage family all flower in their second year. To save their seed, you need to get the plant through winter and let it flower the next spring.

For roots, lift them in autumn, store them in damp sand somewhere cool and replant in spring. Leave cabbage family plants in the ground over winter, with fleece in cold areas, and they’ll send up flower stalks in late spring.

Your first seed saving year

Plan your seed saving alongside your normal growing. Choose which plants you’ll save seed from at planting time, and label them so nobody eats them by mistake.

Our vegetable planting calendar will help you plan the growing side alongside your seed saving.

Getting the best from saved seed

Saved seed gets better when you keep choosing the best plants year after year. Save seed only from plants with the things you want: good health, flavour, early crops, big harvests or coping well with your conditions.

Over a few generations, careful choosing can nudge a variety towards what you like, such as ripening earlier. That’s how old local varieties came about. It’s also the first step into breeding your own plants, and our guide to breeding your own fuchsias from saved seed shows how to cross two parents and raise the seedlings.

At the peak of the season, tie a label on your three best plants of each variety, and save seed only from those. Don’t save from just one plant year after year, as a wider mix keeps the variety strong.

Start with the easy crops this year, keep notes and build up your collection bit by bit.

When you’re ready to sow your saved seeds, our seed sowing calendar shows when each one should go in.

Frequently asked questions

Which seeds are easiest to save for beginners?

Tomatoes, French beans, peas and lettuce. All four pollinate themselves, so open-pollinated varieties come true. You don’t need to worry about varieties crossing or keeping them apart. The seeds are also easy to collect, dry and store.

Can I save seeds from F1 hybrid plants?

You can, but the results are a lottery. Seed from F1 plants grows into a random mix of the original parents’ traits. A few may be good, but most will disappoint. For reliable results, save seed only from open-pollinated or heritage varieties.

How long do saved seeds last?

Most veg seeds keep for three to five years in an airtight container. Some last much longer, and tomato seed can still sprout after many years. Parsnip and onion seed fades fastest, often within a year or two. Always test old seed before you rely on it.

Is it legal to save seeds in the UK?

Yes, saving seed from your own garden for your own use is legal. Plant breeders’ rights don’t cover private, non-commercial use. Selling seed is different, because seed sold commercially must meet seed marketing rules and some varieties are protected.

How do I test if saved seeds are still viable?

Try a simple paper towel test. Put 10 seeds on a damp paper towel, fold it over and seal it in a plastic bag. Keep it at room temperature for one to two weeks and count how many sprout. Eight or more, sow as normal. Five to seven, sow more thickly. Fewer than five, it’s time for fresh seed.

Do I need to ferment tomato seeds before saving?

It’s the best way, but not essential. Fermenting removes the jelly coat that stops seeds sprouting. Put the seeds in a jar with water and leave them for two or three days until mould forms, then rinse and dry. You can just wash the jelly off instead, but it’s fiddlier.

How do I stop different varieties cross-pollinating?

Choose crops that pollinate themselves, or grow just one variety. Tomatoes, French beans and lettuce rarely cross, even side by side. For courgettes and sweetcorn, grow one variety only or keep varieties at least 400m apart. Or hand-pollinate flowers and bag them to keep insects out.