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Seed Saving for Beginners

Why Save Seeds?

Vegetable Cycle Pollination Pollinator Isolation
Distance
Seed Longevity Notes
Bean
A
Self
100'
2-3 yrs
Lose vigor rapidly.
Soybean
A
Self
100'
2-3 yrs
Space farther apart than for market crops.
Beet/Chard
B
Cross
Wind
1/2 mi
3-5 yrs
Beets cross with chards.
Broccoli/Kale/
Cauliflower
B
Cross
Insects
1/2 mi
3-5 yrs
Hot-water treated seeds last only 1 yr. Crossing among brassica species is complex, consult a good reference book.
Carrot
B
Cross
Insects
1500'
2-3 yrs
Crosses with wild species.
Celery
B
Cross
Insects
1500'
2-3 yrs
 
Corn
A
Cross
Wind
1/2 mi
2-3 yrs
Adequate population essential.
Cucumber
A
Cross
Insects
1500'
5-10 yrs
Harvest at yellow blimp stage.
Eggplant
A
Self
150'
2-3 yrs
 
Leek
B
Cross
Insects
1500'
2 yrs
 
Onion
B
Cross
Insects
1500'
1 yr
 
Lettuce
A
Self
50'
2-3 yrs
Start indoors, need long season for seed.
Melon
A
Cross
Insects
1500'
5-10 yrs
Muskmelons will not cross with watermelons.
Mustard
A
Cross
Insects
1/2 mi
3-5 yrs
Crosses with wild species.
Pea
A
Self
50'
2-3 yrs
Do not save seed from diseased plants.
Pepper
A
both
Insects
500'
2-3 yrs
Some varieties cross more readily than others.
Radish
A
Cross
Insects
1500'
3-5 yrs
 
Spinach
A
Cross
Wind
1/2 mi
2-3 yrs
 
Squash/Pumpkin
A
Cross
Insects
1500'
2-5 yrs
moschata 2-3 yrs, pepo & maxima 3-5 yrs. These three species generally do not cross.
Tomato
A
Self
25'-100'
5-10 yrs
Potato-leaf types need the greater isolation distance.
Cycle: A=annual, B=biennial.
Pollination: Self=self-pollinated, Cross=cross-pollinated by another plant.
Isolation Distance: recommended distance by which different varieties must be separated to prevent unwanted cross-pollination.
Seed Longevity: Averages, not guarantees. Seed longevity depends on the conditions under which the crop was grown and how the seeds have been stored.
Minimum Populations: Crossers require minimum populations to maintain vigor and avoid inbreeding depression. Recommended minumums number of plants: 25 cucumbers, squash, melons; 50-100 radishes, brassicas, mustards; 200 sweet corn.

Basic Definitions

Open-pollinated varieties will grow true to type when randomly mated within their own variety. Seed saved from these plants will breed true, provided the plants have been properly isolated from different varieties of the same species.

Hybrid varieties are those produced from the crossing of two different inbred lines. Seed saved from hybrid varieties will not breed true in the next generation.

Amongst open-pollinated plants, self-pollinated (selfers) usually reproduce by using their own pollen. Crossers usually reproduce through the transfer of pollen from one plant to a different plant of the same species.

Botanical nomenclature goes from the general to the specific. Plants are classified into kinds by genus, species, and variety. In Cucurbita pepo Sweet Dumpling, Cucurbita is the genus, pepo is the species and Sweet Dumpling is the variety.

Seed Storage

Keep your seed alive by storing it properly! Humidity and heat are the enemies of seed longevity. Humidity causes the quickest deterioration. Ideal moisture content for most seed is no more than 10-12% so store at low relative humidity. Optimum storage is in a sealed jar in a freezer or refrigerator. Failing that, the sum of temperature plus relative humidity where seed is kept should never exceed 100.

• Never store seed in a humid, warm or sunny spot.

• Don’t ever leave it in a greenhouse or hoophouse for even a few hours.

Most seed stored properly will last for several years. A few seeds are good for one year only, such as onions, parsnips, parsley, chives, shiso, scorzonera, Batavian endive, licorice, pennyroyal, St Johnswort, liatris, delphinium, larkspur, perennial phlox, and any seed that has been pelleted or hot-water treated. If in doubt, try germinating a sample of old seed in moist paper towels.

Seed Longevity for Herbs and Flowers

This information was hard to find. We have integrated results from several tables with our own first-hand knowledge drawn from testing old lots for germination. Seeds stored in less than ideal conditions will have shorter life spans. Plant name is followed by years.

achillea2 dahlia2 oregano2
acroclinium3 delphinium1 pansy2
alyssum3 dianthus3 penstemon2
amaranth3-5 didiscus3 petunia (unpelleted)5
anise3 digitalis2 phlox1
aster1 dill3 poppy3
baby's breath2 fennel3 portulaca3
bachelor's button3 four o'clock2 rue2
basil5+ gaillardia2 sage3
borage5+ hollyhock3 salpiglossis3-5
calendula3 honesty2 salvia1
campanula3 impatiens2 savory3
candytuft2 larkspur1 scabiosa3
caraway3 lavatera3-5 snapdragon3
catnip5 lavender5 statice2
celosia3-5 lemon balm5 stock3
chinese lantern1 lobelia3 strawflower2
chives1 lupine2 sweet pea3
chrysanthemum3 marigold3 sunflower3
cilantro5+ marjoram3 thyme3
clarkia2 nasturtium3-5 tithonia2
columbine2 nicotiana3 zinnia3-5
coreopsis2 nigella1