Saving Your Own Seeds: Beans, Tomatoes and Lettuce for Next Year

There’s a moment in September when the garden stops only giving and starts setting something aside. Bean pods turn papery, an overlooked tomato goes soft, and the lettuce you forgot about is suddenly covered in fluffy tufts. That’s next year’s seed — and three of these crops are simple enough that kids can happily take over the job.

First things first: open-pollinated or F1?

Before you collect anything, check the seed packet the plant came from. If it says F1 or hybrid, save yourself the trouble: seed from an F1 plant produces offspring that often bears little resemblance to the parent — smaller fruit, different growth habit, unpredictable yields. Not dangerous, just disappointing.

What you want are open-pollinated varieties, sometimes labelled as heirloom or heritage. Those pass their traits on reliably. If you can no longer remember where a plant came from, go ahead and try anyway — just treat it as an experiment rather than a plan.

Beans: the easiest place to start

Bush and pole beans are largely self-pollinating. That means what you harvest comes back almost identical next year, even if two varieties grew side by side. Which makes them the perfect first crop for saving seed. Runner beans are the exception: they belong to a different species, are pollinated by bumblebees and cross readily — their seed only stays true to type if no second runner bean variety is flowering nearby.

Here is how: leave a few pods on the plant instead of picking them green. They will harden, turn beige to straw-yellow and feel papery. When the pod rattles as you shake it and the beans inside feel rock-hard, you are there.

If September turns wet, pull the whole plant and hang it upside down somewhere airy and dry to finish ripening. Only then crack the pods open and pick out the beans.

Tomatoes: a short soak makes all the difference

Tomatoes self-pollinate too, so open-pollinated varieties stay true to type. Pick one fully ripe, flawless fruit from a healthy plant — not the last battered tomato off a diseased one.

Halve it, scrape the seeds and their jelly into a jar and add two fingers depth of water. Leave it at room temperature for two to three days. A layer will form on the surface and it will smell sour — that is the point. This brief fermentation dissolves the gel coating that otherwise slows germination.

Then rinse everything through a sieve with plenty of water until the seeds are clean. Good seeds sink, empty ones float and can go. Spread them on a plate or baking paper rather than kitchen towel, where they stick fast.

Lettuce: wait for the dandelion clock

A lettuce that bolted in summer feels like a failure — for seed saving it is exactly right. After flowering it forms small seed heads topped with white fluff, like a miniature dandelion clock.

The catch: they do not all ripen at once. Wait until the first fluffy heads open, then cut the whole flower stalk. Hang it upside down in a paper bag indoors and the rest will finish ripening. After one or two weeks, give the bag a good shake — the seeds drop out on their own.

You do not need to remove every last piece of fluff. It will not get in the way when you sow.

Important: skip courgettes and squash

There is one clear exception here, and it is worth taking seriously. Cucurbits are insect-pollinated and cross readily with one another, including with ornamental gourds from a neighbouring garden. Those crosses can accumulate cucurbitacins — bitter compounds that have been bred out of edible varieties. They survive cooking and can cause severe stomach and bowel upsets.

So: do not save your own courgette, squash or cucumber seed — buy it fresh each year. And regardless of where your plant came from, if a piece of courgette or squash tastes bitter, spit it out immediately and throw the whole fruit away. Do not season around it, do not keep cooking it.

Dry it, label it, store it cool

Every seed needs to dry thoroughly before it goes into a jar, otherwise it moulds. Two weeks in the open somewhere airy indoors — no radiator, no direct sun. A bean is dry when it splits rather than dents as you bite down on it — then spit it back out, raw beans are not edible uncooked.

Then into paper envelopes or screw-top jars, labelled with the variety, the crop and the year of harvest. The year matters: beans and lettuce germinate reliably for around three years, while tomato seed keeps considerably longer if stored cool and dry. A shelf in a dark cellar beats any drawer in a warm kitchen.

In Rootivo you can attach a personal note to any plant in the encyclopaedia — variety name, harvest year, how it performed. Come spring you will know not just what is in the envelope, but why you kept it.

Im Lexikon: Buschbohne