Extension Communications 3614 Administrative Services Building Ames, Iowa 50011-3614 (515) 294-9915

8/11/03

Contacts:
Foy Spicer, Horticulture, yoffoy@iastate.edu
Jean McGuire, Continuing Education and Communication Services, (515) 294-7033, jmcguire@iastate.edu

Yard and Garden Column for the Week Beginning Aug. 15

Harvest Seeds for Next Year's Garden From this Year's Plants

By Foy Spicer
Horticulture Intern
Iowa State University Extension

Out of the necessity of feeding their families, ancestors came to the new world with precious bundles of carefully selected seed. Today we continue to enjoy the seed-saving tradition. Not out of necessity, but to perpetuate family and heirloom plants with desirable characteristics, while also saving money.

Seeds are found in the fruits of plants, like a pea in a pod or an apple seed in an apple core. Sometimes seeds will be attached to shriveled petals, like on marigolds and zinnias. The seeds are ready to harvest when they darken and become dry. Some plants distribute their seed when their seedpods explode, flinging the seeds away from the parent plant. Make sure to harvest before this occurs or fasten a fine mesh or paper bag over the seed heads to catch the seeds.

Once seeds are collected, they need to be cleaned. Remove chaff or any debris by sifting or winnowing. Sifting can be done with seeds that are round and uniform in shape. Two or three sieves or mesh screens will be needed to separate the seeds from the debris. The large chaff can be removed by running the seeds through a sieve with holes that are slightly larger than the seeds. The final sieve should have holes that are slightly smaller than the seeds. This sieve will collect the seeds, but allow the tiny debris and dust to pass through.

Winnowing can be done easily with two cups or bowls and a fan. Drop the seeds from one container to the other in front of a fan. The breeze will blow away any of the lighter debris. When cleaning seeds take care to not break or damage the seed coating.

A slightly different method is followed when collecting seeds from wet fruits such as a watermelon, tomato or pumpkin. Leave the fruit on the plant until it is slightly over-ripe, but not rotting. Then cut the fruit from the plant and scoop out the seeds. They often have strings of pulp attached to them. To remove the fleshy tissue, place the pulpy seeds in a bowl of water and allow them to sit at room temperature for a day. The viable seeds usually sink to the bottom. The non-viable seeds and pulp will float to the top and can be skimmed off. Next, take the clean, wet seeds and lay them on a mesh screen and allow them dry for several days.

Once the seeds are dry they can be stored. Temperature and humidity are important aspects when storing seeds. Both should be constant and low. The temperature should be between 32 and 41 degrees Fahrenheit. The humidity should be between 4 and 13 percent. Most refrigerators have temperatures within this range, but not the correct humidity level. The proper relative humidity can be maintained by placing the dry seeds into paper envelopes that are dated, labeled and sealed. Plastic or non-breathable envelopes should not be used, as they don’t allow moisture to escape, which could lead to decay.

Place the seed envelopes in sealed containers or jars and store them in the refrigerator until next spring. You can also save purchased seeds from one season to the next by closing the packet and refrigerating them in a sealed container. The better the conditions, the longer your seeds will remain viable. When properly stored, most seeds will remain viable for five years or longer.

It is important to note that many of our modern cultivars are hybrids. Seeds from these plants may not grow into seedlings with the same characteristics as the mother plant or may not produce viable seeds. The best plants for seed saving are open-pollinated, heirloom varieties that are true from seed.

For information on specific plant seeds, try these excellent reference books: Seed Sowing and Saving by Carole B. Turner (1997), The New Seed-Starters Handbook by Nancy Bubel (1998) and Seed to Seed by Suzanne Ashworth (1991). Information can also be found online at the following Web sites: http://www.seedsave.org and http://www.seedysaturday.ca/Saving.htm.

Easy Seeds to Save

Flowers
Columbine
Cleome
Larkspur
Marigold
Zinnia
Hollyhocks

Vegetables
Beans
Corn
Peas
Squash

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Editors: No photo is available for this week’s column.

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