How to save your favourite seeds

Saving seed from plants which perform well for you is one way of building up a stock of favourites, with minimal financial outlay.

Saturday, 11th September 2021, 8:00 am
Save teasel seed heads.

This is something that’s certainly worth trying, but don’t assume that it’s all plain sailing.

Whereas vegetative or clonal propagation, which is the rooting of living plant tissue – a stem, leaf, etc results in a specimen identical to the parent – not all seeds reproduce true to form.

The seeds in a packet of F1 (first filial generation) hybrids can be relied upon to produce plants matching the description on the packet.

This is because the plants used to develop F1’s are from “pure lines” developed through in-breeding. However, any seed saved from the resultant plants are termed F2 (second filial generation) and will display a variety of genetic traits.

Best approach then is to start with known performers that have a high germination rate and closely replicate the parent, then experiment with others to broaden your horizon.

I save certain flower and vegetable seeds from summer into deepest autumn, and this began last month with cowslips (Primula veris).

They reproduce true to parent form because they are species plants. This is recognised by the two-word Latin name, the second beginning with a lower case letter v.

An established group either side of the driveway increases year-on-year through self-setting, so there’s no need to fuss over tray sowing and germination requirements.

Woad (Isatis tinctoria), teasel (Dipsacus fullonum), Foxglove (Digitalis purpurea) and Poppy (Papaver somniferum) seeds are also collected because they too are species. In keeping with cowslip, the seed is broadcast where we wish a patch of the plant to develop.

Seed capsules of Wallflower (Erysimum cheiri) are currently ripening, and they perpetuate a link with our medieval past.

Some are grown in a drystone wall. The seed is mixed with soil and water in a container and the resultant mud is pushed into the wall crevices. The seed germinates and gives rise to plants. A messy business, but it works!

Certain vegetables grown from strong lines reproduce close to form, as I have discovered through trials over time.

Pods of runner bean and garden pea are allowed to dry on the plant before storage. Courgette seeds are rescued from marrows before they’re cooked, and those in over-ripe tomatoes are extracted, dried, and saved.

Don’t ignore ‘sow by’ dates!

Once seed has been collected, we need to think of storage and viability.

Humidity and temperature are the key factors in keeping them sound for next year’s crops. They’re best preserved in a cool, dry environment where temperature does not fluctuate.

I have some round film capsules from SLR camera days that provide a dry, sealed home until spring. In the absence of those, brown envelopes will do.

Assuming the seeds collected are viable, they should remain so until the following year.

Beyond that, the percentage germination from each batch will decrease exponentially.

Rather like the food contents of our shopping bags, that have a “best before” date, there is a “sow by” date printed on seed packets.

As a general guide, given a suitable storage environment, most of the popular flower and vegetable seeds can remain viable for two to five years, depending on the type.

This said, the seed firms are rightly, more cautious in stating the anticipated “shelf life” with an acceptable germination percentage in mind.

If you discover an unopened packet of seed several years out of date, run a simple germination test rather than waste time and effort in sowing.

Prepare a soaked paper towel on a saucer, place ten seeds on it and leave for two weeks in a warm, dark place. Be guided by the result.

Stored in ideal conditions, onion, leek, carrot, sweetcorn, pea and bean seed should remain viable for three years.

Most brassicas, beet, celery, lettuce, turnip, cucumber and pumpkin remain sound for at least five years, occasionally ten or more.

And among the common or garden flowering plants, it’s poppy, nasturtium, calendula, hollyhock and antirrhinum seeds that lead the field in longevity.