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 produce seed true to type if they are allowed to cross-pollinate only with other plants of the same variety. If they cross with other varieties of the same species, their seed will not be true.

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.

plantyears
achillea2
acroclinium3
alyssum3
amaranth3-5
anise3
aster1
baby's breath2
bachelor's button3
basil5+
borage5+
calendula3
campanula3
candytuft2
caraway3
catnip5
celosia3-5
chinese lantern1
chives1
chrysanthemum3
cilantro5+
clarkia2
columbine2
coreopsis2
plantyears
dahlia2
daisy3
delphinium1
dianthus3
didiscus3
digitalis2
dill3
fennel3
four o'clock2
gaillardia2
hollyhock3
honesty2
impatiens2
larkspur1
lavatera3-5
lavender5
lemon balm5
lobelia3
lupine2
marigold3
marjoram3
nasturtium3-5
nicotiana3
plantyears
nigella1
oregano2
pansy2
penstemon2
petunia (unpelleted)5
phlox1
poppy3
portulaca3
rue2
sage3
salpiglossis3-5
salvia1
savory3
scabiosa3
snapdragon3
statice2
stock3
strawflower2
sweet pea3
sunflower3
thyme3
tithonia2
zinnia3-5