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close this book The bio-intensive approach to small-scale household food production
close this folder Seed and seedling management
View the document Saving seeds through gardener curators
View the document Why producing your own vegetable seeds is important?
View the document Traditional or indigenous seeds
View the document Seed production
View the document Site selection and timing of seed production
View the document Seed harvesting and seed extraction
View the document Seed drying
View the document Seed storage
View the document Testing seed quality
View the document Nursery techniques for seedlings

Seed storage

The length of time that seeds can be stored depends on: (1) the seed type; (2) its quality; and, (3) the storage conditions.

Factors that Affect the Longevity of Seeds During Storage:

1. Moisture Content of the Seed -- Even if seeds are thoroughly dried, improper storage can still enable them to absorb water. To avoid damage caused by excessive moisture content, (1) store seeds in air-tight containers (bottle with tightly closed metal cover, tin can, sealed thick plastic); (2) keep seeds dry by including desiccants or materials that absorb moisture (example: dry charcoal, dry ash, toasted white rice, lime, silica gel) inside the storage container, and, (3) replace desiccants, such as dry charcoal, dry ash and toasted white rice, each time the container is opened. The moisture content of the seeds can also be kept low if the seeds are sun-dried from time to time.

2. Temperature -- The life of vegetable seeds during storage is prolonged when the storage temperature is low or cold (but not freezing). If a refrigerator or airconditioner is not available, choose a cold place (example: near the river, under trees, underground, inside a clay jar). Ensure that the seeds will not get wet.

As a general rule:

The life of seeds doubles when the moisture content is lowered by 1% or when the storage temperature is lowered by 5°C.

Example:

If the storage life of a seed with 14% moisture content is two years, its storage life can be prolonged to four years if the moisture content of the seed is lowered to 13%.

If the expected life of a seed is three years in a storage room with a temperature of 15°C, its life can be prolonged to six years if the storage temperature is lowered to 10°C.

If both the moisture content of the seed and storage temperature are lowered, the increase in the life of the seed is greater.

Example

Condition

Result

Moisture Content

Temperature

Storage Life

% Germination

13%

30°C

1/2 year

50%

12%

30°C

1 year

50%

13%

25°C

1 year

50%

12%

25°C

2 years

50%

11%

25°C

4 years

50%

10%

30°C

4 years

50%

3. Pests -- Storage weevils, fungi and bacteria shorten the life of seeds during storage. Storage weevils begin to multiply when the moisture content is 10%. Fungi infestation becomes a problem when the moisture content is 13%. Bacteria become a problem when the moisture content is above 20%. To prevent pest infestation, choose only pest-free seeds during storage. Pest problems can also be prevented if the seeds are maintained dry. Materials that prevent or stop the growth and multiplication of pests can also be used. These are:

a. Dry ash and charcoal -- They absorb water inside the storage container. Ash prevents the growth and increase of weevils. Use one-half kilo of ash for every one kilo of seed. Use ash which has been cooled for at least 12 hours to prevent the seeds from burning.

b. Sand -- Mix the sand with the seeds and make sure that the storage container is full so that the weevils cannot move around.

c. Cooking Oil -- Some seeds can be mixed with cooking oil to prevent increase of weevil. The recommended rate is one teaspoon oil for every one kilo of seeds.

d. Lime -- In addition to absorbing moisture, lime can also prevent an increase in the number of weevils. Mix 15 teaspoons (about 50 grams) of lime for every kilo of seeds.

e. Dried and powdered leaves or seeds of different aromatic plants - Weevils are sensitive to odorous plants which prevent their multiplication and cause their death The effect of the plants depends on their preparation, the amount applied and the type of seed and weevils. Some of these plants can affect the seed so it is important to test what is appropriate for a certain kind of seed. Also, make sure that the right amount is applied.

Examples of Aromatic Plants

· Neem -- Dry the leaves or seeds under the sun and grind them to a powder. Mix 3-4 teaspoons (15-20 grams) of powdered seeds (double the amount if powdered leaves are used) for every one kilo of seeds.

· Hot pepper or chili -- Dried and powdered fruits are better than dried whole fruits. Mix 46 teaspoons (20-30 grams) of dried and powdered chili for every one kilo of seeds.

· Black pepper -- Mix 6 teaspoons (30 grams) of powdered black pepper (double the amount if powdered leaves are used) for every kilo of seeds.

Other plants which can be tried:

· Powdered rhizome of turmeric - Mix 4 teaspoons (20 grams) for every kilo of seeds.

· Powdered leaves of mint -- Mix 14 teaspoons (5-20 grams) for every kilo of seeds.

· Powdered seeds of yambean -Mix 1-2 teaspoons (5-10 grams) for every kilo of seeds.

· Powdered leaves of lagundi, mango and tobacco -- Mix 14 teaspoons (5-20 grams) for every kilo of seeds.

4. Other factors -- The storage life of seeds can become shorter if the seeds are overmature, if they came from plants that have been attacked by pests and diseases or if the seeds were damaged during seed processing.

Labeling

Place labels inside and outside the storage container, especially when lots of different types of seeds will be stored. The following should be included in the label: (1) name of seed; (2) date harvested; (3) date stored; (4) date germination test was conducted; and, (5) percentage germination. If necessary, the characteristics of the plant and the seed should also be included.