The Zero-mile Diet: Bringing in the Seeds

The seeds to your next great garden are growing right in your garden.

Credit: Carolyn Herriot

There are no better seeds for your garden than those growing right in your garden

There is a lot to learn from practical experience when it comes to seed saving, so I’d like to share what I have garnered over the past 20 years of doing it. One thing is for sure – there are no better seeds for your garden than the seeds you save from it.

Leeks & onions

Onions and leeks (Alliaceae family) are biennial plants that set seed in the second year. They are cross pollinated by tiny insects, so to maintain varietal purity it’s important that no other alliums are flowering within 1.6 km (1 mile)! Seeds develop in small inflorescences on large globular seedheads and require patience for ripening.

Pictured above: Leeks

TIP: Do the squeeze test before harvesting – if they are squishy they are still maturing. Take leek seedheads that developed around April off around the end of September. I leave them on the top shelf of the greenhouse to thoroughly dry. I then cut the seeds off and rub them between gloved hands to remove the chaff. These seeds are then screened. Allium seeds have a short shelf-life (viability) – one year, two at the most, so let some plants go to seed every year.


Lettuces (Asteraceae family) have “perfect” flowers that are both male and female, meaning they self-pollinate, and because of this you can grow many varieties in the garden without worrying about them crossing up.

Lettuces produce large quantities of seed and you know they are ready when feathery parachutes appear. These seedheads should be cut off before strong winds disperse them. I invert seed stalks into paper bags to dry them; when dry I separate the seeds by bashing the stalks into a wheelbarrow. I clean them using screens, then blow off any fine particles or chaff in a large stainless-steel bowl using my hairdryer on a cold setting.



Cleaning seeds

I use a series of screens with three different sized meshes – one fine, one medium and one large. Wire screening to make these handy screens is available at hardware stores.

TIP: Use a magnifying glass to identify the seeds when collecting, and to inspect cleaned seeds for possible weed seeds or contaminants.

Drying seeds

The two problems most encountered are not drying seeds enough before storing (leading to mould) and harvesting the seeds before they have matured. Lay clean seeds out in saucers in a warm place before storage. Wait until seeds turn light brown on the plant before harvesting, or try a squeeze test for hardness for larger seeds.

Brussels sprouts, broccoli, cabbage, cauliflower, kale, collards, arugula, mustards, turnips, kohlrabi and rutabaga are all members of the cabbage family, Brassicaceae. Although brassicas have perfect flowers, with both male and female, most cultivars are self-incompatible and need insects for pollination to occur. Plants belonging to the same species will cross-pollinate; so to maintain genetic purity an isolation distance of 1.6 km (1 mile) is required. To maintain genetic variability it’s best to collect seeds from a minimum of six plants of the same variety. A copious amount of seed is produced in pods, which turn light brown when the seeds are ready. Sometimes little birds tell you when the pods are ripe! I cut the seed stalks down and invert them into labelled paper bags; labelling with the variety and the date of collection is a good idea for future reference. I keep seeds in this bag until the pods become dry and brittle and many of the seeds have burst. Then I crush the bag lightly with a hammer or roll over it with a rolling pin to release the rest. When stored correctly the seed is good for three to five years.

Tomatoes, peppers & eggplants

Tomatoes, peppers and eggplants belong to the Solanaceae family and are self-pollinating. A few feet of separation between varieties is all that is needed. If tomatoes are potato leafed (a lot of heirlooms are), they have fully double flowers, which increases the chance of cross-pollination. I space these 9 m (30 ft.) from each other for this reason.

Tomato seeds need fermentation to destroy seed-borne pathogens and the protective gelatinous coating around the seed, which inhibits germination. This involves squeezing tomato pulp into a container (I use yogurt tubs), and leaving it to ferment for five days, with a lid on to prevent fruit flies. On the fifth day pour the seeds into a large bowl and fill it with water; the good seeds sink to the bottom, while bad seeds and scum float to the top where they are poured off. Use a sieve to collect the good seeds and lay them out to dry on plates in a warm place. Crumble dried seeds with your fingers to separate any that are stuck together, then dry them again before storing in an airtight container in a cold dark room. Properly stored tomato seeds remain viable from five to 10 years.

TIP: Cut the tomato horizontally to make getting the seeds out easier.


squash blossom
Female squash blossom

Members of the squash family (Curcurbitaceae family) have separate male and female flowers on the same plant and require insects for pollination. You can tell the sex of the flowers by searching for the long stem and pollen on the male, and a small swelling (ovary) at the base of the female. Cucumbers, melons, gourds, watermelon and the four different species of squash do not cross-pollinate with each other, but squash plants of the same species do and need to be isolated by 800 m (½ mile) to maintain varietal purity. You can control parentage by hand pollinating: take pollen from the male flower and apply it to the female flower before it opens, then tape closed. The seeds in the fruit that develop are now certain to have varietal purity. Squash should be left on the vine as long as possible to allow the seeds to mature inside.

Beets, chard & spinach

Beets, chard and spinach (Chenopodiaceae family) are cross-pollinating biennials with fine pollen that can be carried great distances by wind. Beets, chard and spinach plants need an isolation distance of 400 m (¼ mile) from one another to insure seeds come true in the next generation. Seeds are produced in abundance and are light brown when ready for harvesting. Cut the tall seed stalks down and lay them out on tarps in the sun to dry. Strip seeds off the stalk using gloved hands. Screens clean these larger seeds adequately, but I prefer using the hairdryer for the final cleaning to blow away the finer dust.

Peas & beans

The easiest and most fun seeds to save are those of peas and beans, belonging to the Fabaceae family. These legumes are also self-pollinating, which means you can grow several different varieties for seed in a small garden. I leave a buffer zone of 9 m (30 ft.) between the pole beans, and plant another vegetable between the bush beans for extra caution.

TIP: Little white egg masses on pea seeds signify pea weevils. Remove infected seeds and put the rest into an airtight container and freeze for one week. I shuck and inspect pea and bean seeds as soon as possible after collection due to this problem.