Saving Your Own Seed: Open Pollinated Instead of F1

At the end of every gardening season, your finest plants hold a promise for the year ahead. The plumpest bean, the most aromatic tomato, the lettuce that bolted last: their seeds carry the blueprint for the next generation. Saving your own seed is one of the oldest cultural techniques there is, and one of the most satisfying moments in the self-sufficiency year. You close the circle. Instead of buying fresh little packets every spring, you carry your own line forward, a little better adapted to your garden with each passing year.

The catch: not every plant gives you seed that grows back into the same plant. This is exactly where open pollinated parts ways with F1. Once you understand it, you already know at the seed counter in winter which plant will make a good seed mother come autumn. The main harvest season for seed falls between CW 30 and CW 40, so from late July to early October. Which means you are reading this at just the right time, with your beds heading into full ripeness.

Open pollinated or F1: why this is the whole difference

An open pollinated variety has been selected over many generations so that its offspring resemble the parent plant. It is also called "true to type" seed. Sow the seed of an open pollinated Tomato 'Berner Rose' and you get another 'Berner Rose': same growth habit, same colour, same flavour. The variety is stable because its genetics have become uniform over the years.

An F1 hybrid, by contrast, comes from the deliberate cross of two pure-breeding, very different parent lines. The "F" stands for the Latin filia, meaning daughter generation, and the "1" for the first. This first generation is often especially vigorous, high-yielding and uniform. That is called the heterosis effect. The effect is real, but it lasts only one generation.

Because in the genetics of an F1 plant, the two different parental building blocks still sit side by side. When the F1 plant sets seed itself, these building blocks get reshuffled according to Mendel's laws. The result in the F2 generation: everything segregates. From one packet of F2 seed anything can grow, from a dwarf plant to a rampant climber, from sweet to bland. Some plants are even sterile. For you as a seed saver, F2 is therefore a gamble with no prize.

Spotting F1: what to watch for when buying

You do not need to be a geneticist to tell open pollinated from hybrid. A glance at the packet or the variety register is enough.

A second point often confused with F1: cross-pollination. Even an open pollinated variety only gives you true-to-type seed if it has not crossed with another variety of the same species. Squash, cucumber, maize, cabbage and beetroot are cross-pollinators whose flowers are pollinated by insects or wind. Put two squash varieties side by side and they cross freely, and next year your seed brings surprises. For getting started, you therefore leave these species aside for now.

The four beginners: self-pollinators without stress

Seed is easiest to save from self-pollinators. Their flowers pollinate themselves, usually before they even fully open. Crosses are rare, you need no isolation, no covering, no hand pollination. These are your four starter plants:

The tomato is the queen of seed saving: open pollinated varieties barely cross, and a single ripe fruit truss gives you seed for years. Take the seed from a fully ripe, healthy fruit on a typical plant, not from the first or the weakest one.

The bean (bush bean as well as pole bean) is even simpler: leave a few pods hanging on the plant until they are brown, dry and rattling. That takes until CW 38 to 40. Then you shell out the hard seeds. Done. The pea works the same way, only earlier, often from CW 30 onward.

With lettuce you deliberately let a strong plant bolt. It forms a flower panicle up to a metre tall with many small yellow flowers, from which seeds with white pappus hairs develop, similar to a dandelion. This is the moment you sacrifice a little space in the bed, but the seed is worth it.

The rule for good selection

Seed saving is always also breeding on a small scale. Take seed only from the plants you like best: healthy, vigorous, typical of the variety, ideally early or especially aromatic. Over the years your line adapts to your soil, your climate and your taste. Never take seed from the ailing or bolt-prone plant just because it happens to be left over. You pass on what you select.

Fermenting: the trick for tomato and cucumber

Tomato and cucumber seeds sit in a slimy gel coat. This coat contains germination-inhibiting substances that in nature stop the seeds from sprouting inside the mushy fruit. For storage you need to get rid of it. A short fermentation takes care of that, and as a bonus it also reduces seed-borne diseases.

1. Scrape out the pulp. Cut the fully ripe tomato crosswise and squeeze or scrape the seeds together with their gel into a jar. With cucumbers you take an overripe fruit that has turned yellow.
2. Add a little water. Pour in a small splash of water so a mushy mass forms. Set the jar open, or covered with kitchen paper, at room temperature in a warm spot.
3. Let it ferment for two to four days. A layer of mould forms on the surface and it smells sour. That is intended. Stir once a day. Do not wait longer than four days, or the seeds will sprout in the jar.
4. Rinse. Fill the jar with plenty of water. The good, heavy seeds sink to the bottom, empty husks and fruit remains float on top. Pour off the floating bits and repeat until only clean seeds are left.
5. Dry. Tip the seeds onto a glass or ceramic plate, never onto kitchen paper, where they stick fast. Spread them out singly and let them dry through for several days in an airy spot out of direct sun.

Harvesting dry: bean, pea, lettuce and herbs

Everything that is not a juicy fruit, you harvest dry. One simple rule applies here: let the seeds ripen on the mother plant as long as possible, because that is where they finish. Only once pods, capsules or seed heads are truly dry and brown do you cut them off.

With bean and pea you wait until the pods rattle. On a dry day in late summer, often around CW 38, you pick them and shell out the seeds. A note on the bean: raw bean seeds are toxic, but that plays no part in pure seed storage, since you are not eating them.

Lettuce and herb seeds are fine and drop easily. Cut off the whole seed head once it has flowered a third to half over and is partly fluffy already, and let it dry upside down in a paper bag. The seeds trickle out on their own. Then you separate them from chaff and pappus hairs through a sieve or by gentle blowing. That is called cleaning or "winnowing".

Storing properly: cool, dark, dry

Seed is alive. Every seed keeps breathing quietly and uses up its reserves in the process. Warmth and moisture speed that up and let germination rates fall. Your job is to put the seed into a kind of hibernation.

Stored this way, most seeds stay viable for several years: tomato and bean often five years and longer, lettuce and pea two to three years, onion and parsnip seed on the other hand only one year. If you are unsure, do a quick germination test in February: lay ten seeds on damp kitchen paper, keep it warm and moist, and after a week count how many sprout. Six out of ten means: sow more thickly, but it is still worth it.

Where it goes from here

Seed saving is a cycle that deepens over the years. In the first year you might take only tomato seed. In the second, beans and lettuce join in. In the third you start selecting on purpose, and suddenly you have a tomato that cannot be bought anywhere: your line, adapted to your garden. This is exactly where it pays to record in Gartenkern which plant you harvested from and when, so that next spring you know what you are holding in your hand.

When you carry the dried seed through the winter, the arc connects to storing the rest of your harvest. How to bring potatoes, root vegetables and apples through the winter frost-free and crisp, you can read in our piece on storing your harvest in the cellar, sand box and clamp. And if you want to dig deeper into the courgette from the seed to the harvest, the article courgette from variety to harvest walks you through the whole season.