WHAT ARE THE BEST PLANTS TO START WITH?
Obviously, those whose crops are seeds are better than those that are not. Trying to make various plants go to seed is not always as easy as you think. It is normally a question of treating them badly – putting them in a small pot, not watering them so regularly, and just waiting for Mother Nature to do her thing.
The seed saving process involves quite a bit of paperwork so that you know which seeds they are, and if you can find out the exact strain of species you are working with all the better. You need to have a record of when the seeds were taken, and on which day, and even details of whether it was in the morning or afternoon. Also, you need to record what the weather was like and how long the seeds were left to dry (more on that later).
In this way you can compare germination rates over the years for various conditions and begin to learn what affects your seeds.
HOW TO TAKE SEEDS
This depends on the plant (“Obviously!” you all cry). Seeds in pods should be removed complete with the pod as soon as they are full – as though you would eat them – and they should be stored in such a way so that they can dry out without becoming rotten. I pile them up between newspapers in an old beehive. Then, when the pod is completely dry, I split it open so the seeds can be collected and layered between kitchen roll so they can dry too. The old-fashioned way – probably the best way – was to put them in a gardener’s riddle until they were dry.
Seeds that do not come in pods can be collected on the plant. As soon as the flower looks as though it is pollinated, put a plastic bag over it and seal it with an elastic band. Let the seeds form inside and then take the bag away to sift out the seeds from the rest of the contents. Poppy seeds are best collected in this way – for the kitchen as well as for sowing next year.
GENETICALLY PERFECT
All the seeds you collect will be genetically different from the parent stock. This is because of two reasons. Firstly, the pollen comes from another plant; secondly, both the pollen and the unpollinated seed undergo a process called ‘crossing over’. Chunks of the DNA are mixed and reordered before the seed and pollen is finally produced, so even if you have self-pollinated plants, you might get some genetic variation.
In order to ensure that you have a pretty good genetic stock, put a bag over the flower before it is able to be pollinated.
I remember watching Percy Thrower pulling all the stamens off one rose flower and pollinating another rose flower that had its anthers removed. This is how new roses are produced – and you can do the same with vegetables. After artificial pollination has taken place, the flower is then covered in a bag.
NOT FRUIT
In America they went mad in the last 150 years producing new strains of raspberries. Genetically, raspberries get messed up with viruses and they need to be replaced regularly in much the same way as strawberries. Nearly all our fruit is best propagated for the future by taking cuttings and not saving seeds. This is particularly so for apples, where there are so many genetic problems the chances of true-breed success is small.
AFTER DRYING
You need to keep the seeds dry and cool. They do well in packets, absorbent envelopes, and in boxes of newspaper. The containers do not necessarily need to be airtight, and neither do they need to be kept in freezing conditions. You can, if you have the space, put them in plastic containers in the freezer, but you have to be sure the moisture content of the seed is minimal – freezing water expands and can damage the seed.
Make sure everything is labelled, and make a record of the germination rate when you sow them. Don’t sow all your seed at once, because you might just have a disaster! You are looking for a germination rate in excess of 80% – commercial seed sellers have to prove their seeds germinate at an even higher rate than this.
Don’t mix last year’s leftover seeds with next year’s seeds, but do try to keep back small quantities year-on-year. Then you will have a proper seed bank.