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Vernalization is a special method of seed preparation. Seeds are exposed to low temperatures, about 2 – 4 degrees Celsius. For potatoes, the concept of “vernalization” refers to the germination of tubers for an early harvest.
Preparing the tubers
To get a good potato harvest, it is very important to prepare high-quality seed material. For planting, medium-sized tubers are selected, weighing from 70 to 100 grams. It is necessary to carefully examine each tuber, any spots, holes may be signs of infection with infectious diseases or harmful insects.
If the potatoes sprouted during storage, the sprouts should be inspected. Healthy sprouts are pink, greenish or purple in color. They are smooth, thick, elastic.
Often, when examining tubers, one can notice potato tubers with thin, filamentous sprouts. There are many reasons for the appearance of such sprouts, but the main one is the defeat of viral infections. It is impossible to get a crop from such potatoes. If more than half of the potato seeds have such sprouts, it is necessary to replace the planting material completely.
If sprouts have appeared on potatoes, and at least a month before planting, it is advisable to break them off. This will make it possible to wake the dormant eyes of the potato. Planting too long processes is undesirable, they are very easy to break off, they will need more time to adapt to temperature changes.
Timing of vernalization
The vernalization of potatoes before planting begins 30-40 days before planting in the ground. In early varieties of potatoes, sprouts appear a few days earlier than in later varieties.
To determine the time of the beginning of potato vernalization, it is necessary to count 40 days from the approximate date of planting in the ground. If you start vernalization early, the sprouts will be too long, during planting they are easy to injure.
Planting potato tubers in the ground begins when the soil warms up to 6 – 8 degrees. Depending on the method of planting, the temperature is measured at a depth of 20 – 40 cm. It is necessary to prepare shelters for potatoes in case of return frosts.
Vernalization methods
There are three methods of vernalization – dry, wet and combined. For vernalization of potatoes at home, any of them will do.
Dry method
With this method of vernalization, the potatoes are left dry, occasionally sprinkling them. The main advantage of this method is that potatoes are less affected by fungal diseases.
Among fans of growing potatoes, there is often a dispute about how best to vernalize planting material – in the light or in the dark. Supporters of the first method argue that they are right by the fact that under the action of sunlight, solanine is formed in the tubers – a natural insecticide and fungicide. Potato tubers, which contain solanine, are less affected by fungal diseases and harmful insects.
Proponents of the second method motivate their choice by the fact that under natural conditions, the development of potatoes occurs underground and human intervention in natural mechanisms can only worsen yields.
There are several options for placing potato tubers for vernalization:
- Lay out on the floor in one or two layers;
- Place on racks
- Hang on the wall or ceiling in transparent bags;
- String on wire or twine and hang.
The disadvantage of the first option is that you need a lot of free space in a bright, heated room, which is often difficult to provide. If there is such a room, the floor is covered with oilcloth or paper. Potato tubers are laid out in one or two layers, spraying from a spray gun once a day. It is necessary to turn the tubers every 2 to 3 days.
For the second way to vernalize tubers, you will need racks. The distance between the shelves should be at least 30 cm so as not to obscure the sprouting tubers. This option saves space in the room, but requires the purchase of racks or materials for their construction.
The variant with transparent bags is the most economical. Plastic bags are inexpensive and can be placed anywhere. Glazed balconies are often used for these purposes, nails are driven into the walls, on which potato tubers are vernalized. It is necessary to ensure that the air temperature on the balcony does not fall below 5 degrees Celsius.
The fourth method also saves space; strung potatoes can be placed in a room, on a balcony, or on a warm veranda. If the weather is warm outside, garlands of potatoes can be taken outside.
Potatoes prepared by dry vernalization have several sprouts up to 3 cm in size. White dots are visible on the sprouts – the beginnings of roots.
wet way
This method involves placing the potatoes in a humid environment. The most commonly used for vernalization are:
- Sand;
- Sawdust;
- Peat;
- Perlite.
Sand is the least suitable option, it does not conduct air well. Potatoes placed in sand are often affected by fungal infections or rot.
Sawdust conducts air well, but is often unevenly moistened. May contain pathogens of infectious diseases and larvae of harmful insects. It is undesirable to use oak sawdust.
Peat does not contain pathogens of fungal infections, potatoes germinate well in it. It also contains nutrients that can provide additional nutrition to the tubers. The only disadvantage of peat is the danger of waterlogging. It often has a high acidity, it is desirable to add ash to germinate tubers.
Potatoes grown in perlite are not susceptible to fungal diseases. Perlite perfectly absorbs water, it is difficult to overmoisten it.
Before laying the tubers for vernalization, the bottom of the box, where they will be, is covered with paper or plastic wrap, a small layer of wet substrate is poured. Spread potatoes and substrate in layers until the box is full.
The boxes are transferred to a room with a temperature of about 15 degrees. It is necessary to monitor the moisture content of the substrate and the condition of the tubers to prevent drying out.
A tuber ready for planting has a sprout 3–5 cm in size, numerous roots. Tubers should not be allowed to dry out during planting. Before planting potatoes, it is desirable to treat with long-acting insecticides.
Combined method
The essence of this method is that the potatoes are first vernalized in the light, then placed in a moist growing substrate.
Potatoes selected for planting are placed in a bright place, the air temperature of which does not exceed 10 degrees Celsius. Leave for 2 weeks. It is necessary to turn the tubers daily and spray them.
When the potatoes sprout, they are placed in boxes with a moist substrate until the roots form. This process takes an average of 3 weeks. Potatoes of early varieties form roots faster.
The vernalized potatoes are planted immediately from the box where they were germinated in order to avoid drying out of the roots.
Tuber processing
To prevent problems with planting material, tubers must be processed before laying for vernalization.
For the treatment of tubers, the following types of chemicals are used:
- Fungicides;
- Growth stimulants;
- Nutrients;
- Insecticide;
- Disinfectants.
Fungicide treatment is mandatory if potatoes were grown in the rainy season or bought on the market. Wet weather promotes the spread of fungal spores. It is often imperceptible by the appearance of the tuber that it is affected by a fungal infection, the first signs of damage appear during the growing season.
Purchased from an unknown producer, seed potatoes can contain a variety of infectious disease agents that will not only affect the potato crop, but can also infect the soil.
In this case, before laying for vernalization, the potatoes are thoroughly washed with disinfectants, trying not to damage the peel. The washing field is soaked or sprayed with fungicides according to the instructions.
Growth stimulants can reduce the time of vernalization and growing potatoes by 1-2 weeks. As a rule, they contain phytohormones identical to natural ones, which contribute to rapid development and good yields.
Treatment with potassium preparations before vernalization makes it possible to compensate for the nutrient deficiency in the tuber. Potato develops faster, has good stress resistance.
It is very important to treat the tubers from harmful insects, especially if there have been cases of damage by scoops, wireworms or other pests in neighboring areas. Potato tubers may contain insect larvae.
Conclusion
Tuber vernalization before planting does not require much time and effort. Choosing the right method, you can significantly improve the yield of potatoes, reduce the growing time.