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.