How to Save Your Own Seeds

14 September 2012, written by Benedict Vanheems

I was disturbed to read that a small seed company in France lost its case in a recent ruling by the European Court of Justice. This powerful court ruled that the company was breaking the law by selling old, unregistered varieties. In Europe, at least, it seems that a variety can have been in existence for centuries, but unless it's officially registered (a process that doesn't come cheap!) it can't legally be sold. It's no wonder so many heritage varieties have disappeared over recent decades. I'm not sure what the situation is regarding the sale of seeds of unregistered heritage varieties in other parts of the world but I'd be interested to know – please post below if you can shed some light on this.

The perpetuation of heritage, or heirloom, varieties is just one reason why I'd encourage vegetable gardeners to save more of their own seeds. Not only does saving seeds trim the annual seed bill, it increases the chances of precious varieties surviving into the future. Many of these living heirlooms might have been passed down from generation to generation; by saving seeds we can make sure they're available for the next.

Saving for the future

Many of you may have already saved a few of your own seeds. Pole beans are especially easy to collect – simply wait for the pods to dry to a crisp then crack them open to reveal the plump seeds inside. It's what my grandfather did from year to year, saving his pole beans so he could justifiably claim a completely input-free crop that perfectly adapted over the years to his patch of ground. A highly informative guide worth saving is Barbara's Three Ways to Save Tomato Seeds how-to guide.

A clear benefit to savid your own seeds is that varieties will subtly evolve over time to become better suited to your unique local growing conditions. It's natural selection in action, and while you may not have a unique strain after one or two years, perhaps over a few decades your saved seed will become a true local!

When to collect

It's not always obvious when seeds are ready. The correct time to collect seeds from their fruits may differ from the time they are ready to eat. For example, sweet corn kernels must be left to go hard before harvesting – long after the desired 'milky' stage for eating. Perfectly ripe eggplants or cucumbers will naturally fall from the plant when their seeds are ready; harvest when they are edible and the seeds will be far less likely to be viable. In many cases the fruits will be soft and even beginning to rot.

Seed pods and seed heads will usually dry out when they're ready for collection, becoming straw-pale and papery. If you want to hold on to a few of these plants to produce seeds for next year you'll actively want them to 'bolt', or run to seed. Many vegetables, such as beets, spinach and lettuce will stretch upwards to flower and fruit quite soon after the optimal harvesting time. Other vegetables, such as carrots and parsnips, are biennials, putting on leafy/root growth in their first season and flowering early on in the next. To save seeds just allow a few plants to overwinter where they are. In very cold climates you may need to pop a cloche over the top to keep out the worst of the cold. In spring you will be treated to an often stunning flower display before your seeds set (parsnip flowers are particularly stunning and have even featured in some Chelsea Flower Show gardens!).

Of course, a lot of seed collection is commonsense. Just think about what would happen in nature when seeds are ripe and aim to copy that.

Extracting the seeds

Seeds with plenty of pulp, such as tomatoes and cucumbers, can be prepared for storage using Barbara's method above. Vegetables with dry fruits, including all of the cabbage family, carrots, spinach, peas etc, will need to have as much moisture as possible removed from the seeds before storing. This will improve the longevity of the seed and reduce the risk of it rotting in storage.

If you live in a dry climate then fruits can normally be left on the plant to desiccate. Those in moist climates – northern Europe, the Pacific Northwest and so on – may need to bring seed heads, pods and other fruits indoors for drying. Spread them out so plenty of air can get to them – on top of screens or sieves is perfect. When the fruits are paper-dry (at this point the seeds inside will often rattle when shaken) the seed can be extracted by tumbling or breaking it out. Take extreme care to handle the seeds as gently as possible to avoid damaging them.

Preparing for storage

Extracted seeds will need to be properly cleaned before storing to remove any remaining debris, traces of soil, damaged seeds and, crucially, associated pathogens. Seeds from pulpy fruits such as tomatoes can be cleaned in water to remove the remaining flesh from the seeds. If it's not coming off easily try mixing the seed with coarse sand before washing it off (complete with the flesh).

Handle seeds gently to avoid damaging them

Dried seeds can be sorted from its chaff by shaking the whole lot through a series of graded sieves/screens. Stack the sieves with the largest mesh size on top and smallest at the bottom, tip the seeds in and shake. One of the sieves will be just the right size to collect the majority of the seeds, leaving the chaff behind in the remaining sieves. You can also winnow your collected seeds by blowing – carefully – across them, but from my experience this takes considerable skill and patience!

Properly cleaned, dry seeds are best stored in brown paper envelopes in a cool, dark and dry place that is free from fluctuating temperatures. Don't forget to label the envelopes. This is especially important when collecting seed from different varieties of the same family (have you ever tried to tell the difference between a radish seed and a cabbage seed?). With any luck your seeds will be more than ready to germinate the following spring, a prospect second only in satisfaction to that joyous moment of harvest.

By Benedict Vanheems.