Seed Stratification - What Is It

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Seed Stratification - What Is It
Seed Stratification - What Is It

Video: Seed Stratification - What Is It

Video: Seed Stratification - What Is It
Video: How and Why to Stratify Seeds - What is it & What Seeds Need It? 2024, March
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Stratification is a seed pretreatment method that simulates winter conditions in which the seed stays in nature before germination. The seeds of many plant species must go through the dormant stage of the embryo. Otherwise, they will not germinate at all. Stratification is used most often for horticultural seeds.

The embryo in the stone seed
The embryo in the stone seed

What is stratification for?

Stratification is a word of Latin origin. Literally translated, it means "bundle". Previously, we called this method "sanding". The seeds of stone fruit and pome crops were covered with sand and kept for several months at low positive temperatures. This technique significantly increased seed germination.

Why was this done? In winter, in nature, the seeds of many trees and shrubs fall to the ground in autumn, when conditions for germination are still preserved. If the seeds did not have a dormant period, the seedlings would be destroyed by the autumn frosts.

The seeds of other trees and shrubs, on the other hand, hang on the branches for a long time. They fall in late autumn or winter. Protected by a hard shell, the seeds are well preserved until spring under the snow.

During this period, important physiological processes take place in the seeds. With the right temperatures and sufficient air, the seeds prepare for germination. Their shell softens, complex organic substances turn into simple ones, easily accessible for assimilation by the embryo. The stratification method for seeds with tight germination is artificially created conditions similar to those in which they exist in the natural environment.

Seed stratification methods

Now two types of stratification are used: warm and cold. With warm stratification, the soaked seeds are placed in conditions with high humidity, sufficient air flow and a temperature of 10-35 ° C. Warm stratification is usually needed for seeds with an underdeveloped embryo, for example, lemongrass seeds. For seeds of individual plants, it is recommended to perform stratification in two stages. That is, first in a warm way, then in a cold way.

With the cold method of stratification, for most crops, the optimum temperature is from zero to plus five degrees. The seeds are soaked in water for several days. At the same time, the water is periodically changed. It is also recommended to disinfect the seeds with a solution of potassium permanganate. Then the seeds are sprinkled with sand and other substrate (peat, sphagnum moss). A container with a mixture of seeds and substrate is placed in a refrigerator or basement.

Seeds of different crops have different periods of stratification. Its duration can range from two to three weeks to seven to eight months. Therefore, before starting the stratification of seeds of specific crops, it is necessary to first study the recommendations of specialists on its duration and conditions.

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