Saving Seed: An Introduction

Fall 2010
Roberta Bailey collecting seed from 'Kniola’s Purple' morning glory
Roberta Bailey collecting seed from ‘Kniola’s Purple’ morning glory. Rob Lemire photo.

By Roberta Bailey

Have you noticed that you can’t buy ‘Lutz’ beet seed anymore? ‘Lutz’ was the victim of a few seed company mergers and a lack of attention in the seed industry to low-profit, open-pollinated varieties. A few companies listed it, but the variety was not truly ‘Lutz.’ One company is said to have a true strain.

In 2009, I acquired six packets of ‘Lutz’ from six seed savers through the Seed Saver’s Exchange. I grew them out, and five were the true, green leaf, winter storage beet. I selected the best roots and stored them in my root cellar last winter. In late April, I planted each root about 20 inches apart, and they grew to produce 5-foot-tall seed heads loaded with seed clusters. They were ready for harvest in August, and now I have a generous supply of my favorite storage beet.

Why Save Seed?

There are as many reasons to save seed as there are seed savers and varieties. Some people receive a rare heirloom seed variety, and the only way to grow that plant again is to save the seed.

Saving seed links us to our ancestors.

People save seed for political reasons – to know it is free of genetically engineered material and that our seed dollar is not supporting companies engaged in genetic engineering.

As seed companies consolidate, they often drop varieties that do well in specific areas in favor of those that perform uniformly across the country, so your favorite variety may disappear.

Even though open-pollinated varieties can be as vigorous as hybrids if the breeding is done, they are being edged out by high profit hybrids, by the ability to control sales and make greater profits. Few breeding efforts are going into improving or maintaining the genetic quality of old varieties, so, like ‘Lutz,’ they disappear from the market. (Work by the Organic Seed Alliance, which supports ethical development and stewardship of the genetic resources of organic seed, is an exception; see

Roberta Bailey with 'Lutz' beet seed
Bailey with ‘Lutz’ beet in full seed production. Rob Lemire photos.
'Lutz' beet seed crop

A good example is the state of shell, snap and snow peas. Few companies are investing in roguing or pulling off-types from their fields. Unless you save your own pea seed, it is difficult to get clean seed.

Local seed makes better local food. Each time a seed is saved from a plant, it is evolving and changing, adapting to your soil, weather and pest conditions, and is subject to the selections you make.

Growing Plants for Seed

When you decide to save seed, decide on your goals. They may include trying to save an heirloom and keep it as close to its parent as possible; selecting for early ripening in the North or for certain pest or drought resistance; selecting for uniformity of the plants or fruit or for a particular plant habit; selecting for flavor, storage quality, or flavor after three months in storage; or keeping seed true to type. One approach is to save from all the plants in a row or block, because you don’t know what you are selecting out. We are limited by our imagination.

Plants are classified by family and then genus and species. When you see the Latin name for a plant (e.g., Daucus carota for carrot), those are the genus and species names. Classification helps us identify plants and figure out whether they will cross pollinate or not.

Open-pollinated varieties grow seed that will produce the same true variety for generations. Hybrid varieties are the offspring of a cross between two different parent varieties. Seed saved from a hybrid will not produce that same hybrid plant, but instead some genetic combinations of the two original parents.

Some plants, such as peas, beans, tomatoes, peppers and lettuce, are self-pollinating. You can save the seed from nonhybrid varieties of these crops, and it will grow true to type the next year. All of the fruit on the plant, big or small, will have the same genetic makeup. To maintain a full array of the plant’s genetic diversity, grow and save seed from 20 or more plants. If you save seed from one self-pollinating plant, it will grow fine, but you are narrowing the genetic diversity.

Starting with self-pollinated varieties is the easiest way to begin saving your own seed. If you decide to save some tomato seed, plant those plants as far as possible from your other tomatoes to reduce the small chance of crossing. Tomato varieties with large, potato-like leaves will cross with each other, and individual double blossoms on any tomato plant can be insect-pollinated because their flower structure differs from single blossoms, thus these can be crossed with another variety. If possible, isolate varieties by about 25 feet.

Cross-pollinated plants, such as brassicas, corn, carrots, beets, squash, cukes and melons, rely on pollen from other plants to produce viable seed. They need much larger populations to maintain health and vigor. Grow a minimum of 25 to 100 plants – and at least 200 for corn.

Cross-pollinated plants need isolation distances of 250 feet to many miles from other varieties of plants in the same species. The easiest approach is to grow only one variety of a given species. Tall barriers, such as a corn patch or row of trees, can break insect flight patterns and reduce wind, thus reducing the distances needed between varieties that could cross pollinate.

A physical barrier such as a screen cage or row cover can keep the seed crop isolated. I use wire hoops and row covers on some seed crops to keep them pure. I also alternate years, growing one variety one year and another the next. My ‘Lutz’ beet seed crop produced enough seed to last five to 10 years, leaving me free to produce other beet seed crops in the interim.

Think about spacing. A tomato or pepper plant does not need any more space as a seed crop, but a spinach, lettuce or carrot crop does, because the second-year, seed-producing plants are so large. My beet plants took up almost 2 feet each. A lettuce plant will spread to 1-1/2 or 2 feet. I give my seed crops extra minerals (usually as Azomite) to help feed the seed production.

Good record keeping is essential. Label your seedlings, then the planted rows, and the stored seed. Keep a map as a backup record, in case a critter eats the row marker or weather washes out the ink. When I harvest seed I label the harvest bucket and throw the row marker inside the container as well.

If you notice an “off-type” plant – one that is very different from the others – rogue it (pull it out). Likewise, pull any diseased plants. Roguing will keep your seed pure and healthy. Sometimes a variety takes a few years of roguing before no off-types occur.

You can save seed from an interesting off-type and grow it out the next year to see what happens. You may be on your way to creating a new variety, or at least embarking on a little botanical adventure.

Harvesting and Storing Seed

Seed crops are harvested at different times than food crops. Peas and beans need to dry on the plant. I often ribbon off an entire section of a row and save all the seed from that section, leaving it long after the rest of the plants have been removed. Watch the pods; once they are dry but not shattering, they are ready to harvest. With peas, I find it easiest to hand pick the pods, at least on a small scale. With beans and soybeans, I harvest entire plants and hang them until they are very dry. Then I thresh them in a clean trash can or bucket. The chaff can be blown off in the wind or by fan or sifted through a screen.

Flower heads are often hand harvested as they dry. Morning glories and vining crops often mature their bottom seed husks or pods first and progress up the vine as the season goes on. I harvest morning glory seeds every three or four days, rubbing each papery husk by hand and catching its four seeds in my palm. Spread the seed heads to dry, then abrade them to free the seed, and winnow or screen away the chaff. If saving seed for your own use, a bit of chaff does no harm.

Tomatoes, peppers, eggplant and cucumbers can be picked as individual ripe fruit. Let the fruit become very ripe to over-ripe to ensure mature seed. Leave cucumbers on the vine until they mature past the yellow blimp stage. Eggplant should be starting to brown and rot. Tomatoes and peppers need to be very ripe or just past ripe – or picked close to ripe, then stored until fully ripe to over-ripe, a process called “after-ripening.”

You can cut peppers open and remove and dry the seed.

Tomatoes and cucumbers are “wet” seed: They have a gel sac around each seed that is actually a sprout inhibitor that keeps the seed from growing inside a wet fruit. They need to be fermented to remove the gel sac.

Squeeze the tomatoes or scrape the seed from the tomato cavities into a labeled bowl or bucket. Cover it to exclude flies. Allow it to ferment for two to three days or until the gel sac is gone. Watch it closely, as once the sprout inhibitor is gone, the seed will begin to sprout. The gel ferments rapidly in hot weather and slower in cold temperatures. A white mold may start to grow. That’s fine.

Once fermentation is done, add water to the seed slurry. The good seed will sink and the immature seed will float along with the pulp. Pour off the pulp. Add more water and continue to pour off pulp until all that remains is clean seed on the bottom. Pour this into a strainer and drain it. Then spread it to dry in a cool, airy place. I spread my seed on newspaper. Paper plates also work, but paper towels are so fibrous that seed sticks to them.

Label the newspaper or paper plate. When the tomato seed is half dried, stir it to make it less clumpy. Once dried, break up seed clumps and pack them for storage.

Eggplant can be grated or put through a food processor, then added to water. The seed will sink and the pulp will float.

Seed should be dried to a brittle state, ideally to less than 14 percent moisture. Beans should not give if you bite them. Tomato seed should have no moistness to it. For extra insurance, small seed can be further dried in a silica gel for seven days.

Store dried seed in glass jars, plastic bags or paper envelopes. Glass is best, as it does not allow moisture into the seed.

Store seed in a cool, dry place – ideally at less than 50 F and at a relative humidity level below 50 percent. For every 10 degrees colder, seed longevity doubles. I store my most valuable seed in glass canning jars in the freezer. When taking it out, allow the jar to come to room temperature before opening it in order to avoid condensation on the seed.

Seed Longevity

Different types of seed have different life spans. Many retain good germination for only a few years, others for many more years. (See references.) The classic one-year wonders are parsley, parsnip, onions, larkspur and delphiniums. They may last a second year, but germination and vigor will be much lower. Homegrown onion seed often lasts a few years. In general, legumes and carrots last three years; squash, four years; brassicas, eggplant, peppers and tomatoes, five years; and lettuce, three to six years.

You can do a simple germination test by loosely rolling 50 to 100 seeds in a moist, white paper towel, keeping it covered and slightly moist, and sprouting the seed. Most seed will sprout in four to 14 days. If it takes longer, you may want to buy or grow a new seed crop.

This article is just a brief introduction to seed saving. See for specific seed crop production techniques, isolation distances, designs for seed cleaning equipment, a seed longevity table, and more.

Suzanne Ashworth’s Seed to Seed – Seed Saving and Growing Techniques for Vegetable Gardeners is the classic, indispensable reference.

Seed Saver’s Exchange in Decorah, Iowa, has thousands of seed savers who exchange seed through an annual yearbook. (

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