[ Planter ] [ Garden Spot ] [ Garden Tips ] [ Recipes ]

Germination

Source:  Univ. of Nebraska at Lincoln, Extension Service

A successful garden begins with the selection and use of high quality seed of adapted superior varieties. Start by purchasing seed from a reputable seed company. Save records of your seed orders, so if you do have a complaint you can contact the sales company. Saving records of your seed orders is also useful for keeping track of the varieties you planted.

Storing Seed

Often crop seed is left over in a package after planting. This excess seed can be saved for next year's garden, usually with little loss in germination. Seed stored for more than one year, however, will require additional care to insure high germination for future use.

Storage temperature, relative humidity and seed moisture are the important factors in determining how long seed can be stored without loss of germination. The storage life of seed also varies greatly with species (Table I).

In general, longer seed storage life is obtained when seeds are kept dry and at low temperatures. Let seeds air-dry for several weeks before storing. Do this when the relative humidity is low and the air temperatures are warm. Spreading the seed out in direct sunlight for 6 to 8 hours works well, as long as the seed temperature does not generally exceed 100F. Drying the seed in shade is usually better. The dry seed should be placed in packages and stored in moisture-proof containers. Containers such as sealed cans or jars with air tight caps work satisfactorily. Storage temperatures between 35F and 50F are satisfactory when the moisture content of the seed is low.

An alternate method of keeping seeds dry is to place them in a sealed jar with calcium chloride, silica gel or powdered milk. These substances should not touch the seed. These products absorb moisture from the seeds. Use enough of the product or replace it as needed so that the moisture absorbed from the seed will produce no visible change in the product used.

Beans, peas and okra may develop "hard" seeds if their moisture content is reduced to 7 percent or below. This seed will not germinate satisfactorily. "Hard" seed will germinate better if exposed to a humid environment for several weeks before planting.

Germination

It is a good practice to check seed which has been stored for more than one year for germination (Table II). If germination is poor, discard it and buy fresh seed. To test for germination, place a counted number of seeds (such as 25 or 50) between paper towels, strips of soft muslin or blotting paper in a petri dish, baking dish or similar container. Label each "lot" of seed with the variety name. Moisten the seeds, and cover the container to prevent the seeds from drying out. Hold at a temperature of 70 to 75 F. Remove and count the seeds as they germinate. Make your final count at the end of two to three weeks, when all the seeds have had ample time to germinate. Compute the percentage of germination.

Seed "lots" with lowered germination may still be safe for planting if they are sown at higher rates than usual. Also remember that weakly sprouting seeds have a high mortality rate when planted in the soil.

Germination conditions should be optimum when the seed is planted outdoors in the garden or indoors for transplants. This will not only increase germination percentage for older seed but will also insure high germination for fresh seed.

Table II lists information about seed germination for the common vegetables. This table is a guide for comparisons when calculating germination percentages and when germinating seed for home garden use. Germination requirements will vary with seed source, seed storage conditions, age of seed and the environmental conditions under which the seed is germinated. Minimum Federal Standards for vegetable seed germination are also included.

Table I. Seed weight and longevity for home garden vegetables.

Crop Seeds per Ouncea Relative Longevity under Cool, Dry Condition (Years)bc
Asparagus 700 3
Bean, Lima 25 - 75 3
Bean, Snap 110 3
Beets 1,600 4
Broccoli 9,000 5
Brussels Sprouts 8,500 5
Cabbage 8,500 5
Carrot 23,000 3
Cauliflower 9,000 5
Celeriac 70,000 5
Celery 70,000 5
Chicory 26,000 5
Chinese Cabbage 18,000 5
Cucumber 1,100 5
Eggplant 6,000 5
Endive 26,000 5
Kale 9,500 5
Kohlrabi 9,000 5
Leek 11,000 3
Lettuce 25,000 5
Muskmelon 1,200 5
New Zealand Spinach 350 5
Okra 500 2
Onion 9,000 1 - 2
Parsley 18,000 2
Parsnip 12,000 1 - 2
Pea 75 - 90 3
Pepper 4,500 4
Pumpkin 200 4
Radish 3,000 5
Rutabaga 12,000 5
Salsify 1,900 2
Spinach 2,800 5
Squash 100-300 5
Sweetcorn 120 - 180 1 - 2
Swiss Chard 1,500 1 - 2
Tomato 11,000 4
Turnip 14,000 5
Watermelon 200 - 300 5

aSeeds, The Yearbook of Agriculture. 1961. Stefferud, A., Editor. The United States Government Printing Office.
bHandbook for Vegetable Growers. 1960. Knott, Joe. John Wiley & Sons, Inc.
cVegetable Growing Handbook. 1979. Splittstoesser, W.E. AVI Publishing, Inc.

Table II. Germination data for home garden vegetable seed.

Crop Minimum Percent Germinationab Germination Temperatureb Days to Germinate Under Optimum Temperature & Moisture Conditionsc
Min F Opt. F Max. F
Asparagus 60 50 75 95 10
Bean, Lima 70 60 85 85 6
Bean, Snap 75 60 80 95 7
Beets 65 40 85 95 4
Broccoli 75 85 4
Brussels Sprouts 70 80 4
Cabbage 75 40 80 100 4
Carrot 55 40 80 95 6
Cauliflower 75 40 80 100 5
Celeriac 55 70 11
Celery 55 40 70 85 7
Chicory 65 80 6
Chinese Cabbage 75 80 4
Cucumber 80 60 95 105 3
Eggplant 60 60 85 95 6
Endive 70 80 6
Kale 75 80 4
Kohlrabi 75 80 4
Leek 60 70 7
Lettuce 80 35 75 85 3
Muskmelon 75 60 90 100 4
New Zealand Spinach 40 70 6
Okra 50 60 95 105 6
Onion 70 35 75 95 6
Parsley 60 40 75 90 13
Parsnip 60 35 65 85 14
Pea 80 40 75 85 6
Pepper 55 60 85 95 8
Pumpkin 75 60 95 100 4
Radish 75 40 85 95 4
Rutabaga 75 80 4
Salsify 75 70 6
Spinach 60 35 70 85 5
Squash 75 60 95 100 4
Sweetcorn 75 50 95 105 3
Swiss Chard 65 40 85 95 4
Tomato 75 50 85 95 6
Turnip 80 40 85 105 3
Watermelon 80 60 95 105 4

aMinimum percent germination to federal standards.
bHandbook for Vegetable Growers. 1960. Knott, J.E. John Wiley & Sons, Inc.
cSeeds, The Yearbook of Agriculture. 1961. Stefferud, A., Editor. The United States Government Printing Office.