Buying seeds is an expensive business, and while there are few more enjoyable winter pastimes than sifting through gardening catalogues, there are few of us that don't wince when we tot up the total at the end of the evening. Gathering and saving seeds from our own gardens is a practice that has gone out of fashion, partly due to the prevalence of F1 hybrid plants (the seed of which cannot be saved) but more than that, simply from getting out of the habit.  There are, however many dozens of garden and allotment plants that still come true from seed and it is a bounty that is simply going to waste.

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Saving seed is a relatively quick and easy process which requires no specialist equipment and little in the way of specialist knowledge. It helps however to have a basic grasp of the process of how seeds are made.

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Pollination and F1 hybrids

In flowering plants pollen must be released from the male part of the flower, the anther, and be carried either by gravity, wind, water, insect or animal to land on the female part of the flower, the stigma. The pollen grain then germinates (just like a seed) and sends a tube down the style (part of the female appendage) where it searches out and finds the ovary. The male cells that are transported at the tip of the pollen tube then fuse with the ovule, the egg cell, which resides inside the ovary. In this way a seed is made.

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Some plants have ‘perfect’ flowers, which means that each individual flower will have both male and female parts. These can be self-fertile (like a pea flower) or self-infertile (like radishes). Other plants have ‘imperfect’ flowers, but carry them on the same plant (like the separate male and female flowers found on members of the squash family) and are called monoecious , while still others have imperfect flowers with only male or only female flowers on each plant (like many of the cucumbers) and they are called dioecious. In the last case, obviously, you will need both the male and the female plants in order to produce seed.

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Some plants, like most tomatoes, are usually self-pollinated, the stigma being completely enclosed within a dome of fused anthers. The pollen from the anthers drops directly onto the enclosed stigma and pollination occurs. Others, like French beans, pollinate themselves at night, before the flower opens, but can occasionally be pollinated by insects as well.

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Some plants are promiscuous and will cross with anything that is remotely related while others are more selective. The clue to whether a plant will cross can usually be found in the Latin or botanical name of the plant. While squash plants are notoriously promiscuous, they will still only cross with plants of the same Genus and species, so Cucurbita pepo, the variety of squash that includes courgettes will not cross with Cucurbita maxima, the species that includes giant pumpkins, but all the various courgettes will cross with each other and all the giant pumpkins from the maxima species will cross with each other.

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It is possible to control the parentage of your seeds by various means. You can isolate the plants either in a closed greenhouse or a purpose built cage made out of fine mesh or a netting sleeve hung over bamboo stakes, or by enclosing an individual flower in a paper bag at the crucial time, or, in the case of squash and pumpkins, simply by closing the flower by placing an elastic band around the petals to exclude insects.. You can hand-pollinate by brushing the pollen from a desired parent plant onto the stigma of the other chosen parent with a soft brush, or by plucking the male flower and dusting the pollen directly by this means. This method is commonly used to select seed from plants in the pumpkin and squash families.

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While onions and leeks won’t pollinate each other, all varieties of leeks and all varieties of onions will cross. Solve this problem by selecting a small group of plants, isolate them just before the flowers open and, when they are ready for pollination, remove the mesh from a group of plants and carefully brush your pollinating brush over the flowers several times. Do this on a fine day in the morning. As soon as you have finished, net the group again and move on to the next group. Just remember to wash your brush thoroughly before moving to a different variety of onions and to keep any foraging bees or other insects away while the mesh is off.

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Another way to reduce the possibility of cross-breeding is to select your seed bearing plants from the centre of a group of plants, such as growing a block of broad beans and only selecting seed from plants in the centre of that block. This won’t guarantee the purity of the seed, but it will greatly reduce the amount of contaminating pollen, as bees and other pollinating insects will work a patch from the outside in and by the time they reach the centre, most of the pollen they are carrying will be from plants from your block.

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You can also provide a barrier between groups of plants by growing a tall dense crop to interrupt the travel of wind-blown pollen or to deflect bees already laden with pollen from another group of plants.

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Another method, if there are no contaminating species nearby except those under your control, is to mature seed from one variety at a time; allow your red onions to mature this year, your white, next year and your yellow the following year, for example. Properly stored seed will last usually for a minimum of 3 years, so it isn’t necessary to save seed from all your plants every year. The same can be done with the various members of the cabbage family, and some of the carrot family.

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Always look at the individual plants from which you intend to select seed; go for strong, healthy plants, bearing the characteristics that you want to replicate. Reject any plants that depart from the ideal in any way…with lettuce for instance, don’t choose to save the seed from the first plant that flowers and sets seed, because you will by default be selecting plants that bolt, a characteristic that you want to avoid at all costs.

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Open pollinated plants are all viable stock plants. F1 hybrids however are the result of years of selective inbreeding of two separate populations of unrelated plants. Pollen from one population is used to fertilize the ovaries from the other population to produce seed that will grow into a plant will have characteristics of both the parent lines. These hybrids will be imbued with a burst of vigour drawn from both parents, but it will only last for that one generation. Any attempt to save seed from F1 hybrids will be disappointing and will not have the characteristics of the parent plant. Open pollinated plants however will not be identical, year on year, but will be have a strength and vigour that continues through the generations. Some genus and species will remain pretty much constant, while others will show remarkable variability.

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Keeping a pool of breeding plants

In order to maintain the viability of your plants so that you don’t need to buy in more seed in the future it is advisable to grow several plants from which you intend to save seed. In other words, if you can, don’t select all your seed from the same plant, because if you do that year on year, the gene pool will be diminished and the vigour of the plants will be lost. 

 

Drying And Storing Your Seeds

All the seeds that you will be saving from your garden will need be dried and stored.   Collect flower seeds (for instance poppies or onions)  by cutting the stems, enclosing the mature heads in a paper bag and suspending them upside down in a warm, dark, dry place until the flowers release the seeds and they drop to the bottom of the bag. Once that happens the stems and old flowers can be discarded and the seed packaged into a clean envelope, labelled and stored in a sealed container.

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Other plants, like peas and beans, can be matured on the plant and then picked and processed.

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Plants with wet seeds, like pumpkins, squash, aubergines, melons and tomatoes require an extra step in order to mature the seed before cleaning and drying. Drying your seed is the most important part of the process, after ensuring the seed is mature and ready for harvest.  If incompletely dry, seed will soon use up its reserves of energy. First ensure that you harvest on a bright sunny day. Never collect seeds in the rain or before the dew has had time to evaporate completely. Once gathered, spread the seed out on a sheet of newspaper or, if the seed is  wet or enclosed in jelly, like tomato seeds, spread them out on a plate or a sheet of glass, never on paper because the fleshy seed would adhere to the paper.

Once dry to the point of crispness, you need to get rid of the very last remnants of moisture by storing them for several days in a glass jar filled with dry rice. First extract the moisture from the rice by spreading it over a baking tray covered with baking parchment and baking it in the oven for 20 minutes. Pour the hot rice immediately into a large, dry, glass jar and seal with the lid. When the rice is completely cool add your seeds, neatly encased in a small bag. It is possible to make a number of these little bags by sewing across the leg of a pair of tights.  The rice behaves the same as those little packets of silica gel that are found in so many everyday items from shoes to cameras by absorbing the moisture from your seed.  Once completely dry transfer the seed to an envelope, label and store in an airtight container. Most seeds will keep for several years if properly dried and stored.

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If you intend to maximise the promise of your seed gathering by attending seed swaps or using an online forum to exchange seeds, you must be sure that your seed is as pure as possible and that you label it with as much information as you can.

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Sometimes seed, particularly larger seeds from bean and pea families can show signs of infestation by boring grubs. If you notice any holes in your dry seeds, dry them as usual and pop them in the freezer for five days or in a fridge for at least seven.

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Seed swaps and online bartering

Seed swaps are great ways of making the most of your bounty.  Of course gardeners have always exchanged seed between themselves, but the first formal swap in this country took place in Brighton and Hove in 2002 and from there the phenomenon grew until now there are seed swaps all over the country and most garden shows, large and small, now hold seed swaps as part of their program. 

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However, if getting to one of these events is impossible, the next best thing is to visit one of the many online forums, often hosted by individuals or garden groups, and offer your seeds for barter to other seed saving enthusiasts.