Content
Vernalization is a special method of preparing seed material. Seeds are exposed to low temperatures, about 2 - 4 degrees Celsius. For potatoes, the concept of “vernalization” implies the germination of tubers to obtain an early harvest.
Tuber preparation
To obtain 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 or holes may be signs of infection by infectious diseases or harmful insects.
If potatoes have sprouted during storage, it is necessary to inspect the sprouts. Healthy sprouts are pink, greenish or purple in color. They are smooth, thick, elastic.
Often, when examining tubers, you can notice potato tubers with thin, thread-like sprouts. There are many reasons for the appearance of such sprouts, but the main one is viral infections. It is impossible to get a harvest 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 appear on the potatoes, and there is still at least a month before planting, it is advisable to break them off. This will make it possible to awaken the potatoes’ sleeping eyes. Planting shoots that are too long is undesirable, they are very easy to break off, and they will need more time to adapt to changing temperatures.
Timing of vernalization
Vernalization of potatoes before planting begins 30–40 days before planting in the ground. In early potato varieties, sprouts appear several days earlier than in later ones.
To determine the time of the beginning of vernalization of potatoes, it is necessary to count 40 days from the approximate time of planting in the ground. If you start vernalization ahead of schedule, the sprouts will be too long and can be easily injured during planting.
Planting potato tubers in the ground begins when the soil warms up to 6 - 8 degrees. Depending on the planting method, the temperature is measured at a depth of 20–40 cm. It is necessary to prepare shelters for potatoes in case of return frosts.
Methods of vernalization
There are three methods of vernalization - dry, wet and combined. Any of them is suitable for vernalization of potatoes at home.
Dry method
With this method of vernalization, the potatoes are left dry, occasionally sprayed. The main advantage of this method is that potatoes are less affected by fungal diseases.
Among those who like to grow potatoes, a debate often arises about how best to vernalize planting material - in the light or in the dark.Proponents of the first method argue that they are right by the fact that under the influence of sunlight, solanine, a natural insecticide and fungicide, is formed in the tubers. Potato tubers that 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, potato development occurs underground and human intervention in natural mechanisms can only worsen the yield.
There are several options for placing potato tubers for vernalization:
- Place 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, sprayed once a day with a spray bottle. It is necessary to turn the tubers over every 2-3 days.
For the second method of vernalizing tubers, you will need racks. The distance between the shelves should be at least 30 cm so as not to shade the sprouted tubers. This option saves space in the room, but requires costs for the purchase of shelving or materials for their construction.
The option with transparent bags is the most economical. Plastic bags are inexpensive and can be placed anywhere. Often, glazed balconies are used for these purposes; nails are driven into the walls, on which potato tubers are vernalized. It is necessary to ensure that temperature The air on the balcony did not drop below 5 degrees Celsius.
The fourth method also saves space; the strung potatoes can be placed in the room, on the balcony, or on the warm veranda. If the weather is warm, the potato garlands 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 method
This method involves placing the potatoes in a humid environment. For vernalization the following are most often used:
- Sand;
- Sawdust;
- Peat;
- Perlite.
Sand is the least suitable option; it conducts air poorly. 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 not advisable to use oak sawdust.
Peat does not contain pathogens of fungal infections, potatoes grow 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 high acidity; to germinate tubers, it is advisable to add ash.
Potatoes grown in perlite are not susceptible to fungal diseases. Perlite absorbs water well; it is difficult to over-water it.
Before laying the tubers for vernalization, the bottom of the box where they will be is covered with paper or plastic film, and a small layer of wet substrate is poured.Lay out the 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 measuring 3–5 cm and numerous roots. The tubers should not be allowed to dry out during planting. Before planting, it is advisable to treat potatoes with long-acting insecticides.
Combined method
The essence of this method is that potatoes are first vernalized in the light and then placed in a moist substrate for growing.
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 over and spray them daily.
When the potatoes sprout, they are placed in boxes with a moist substrate until roots form. This process takes on average 3 weeks. Potatoes of early varieties form roots faster.
Vernalized potatoes are planted directly from the box where they were germinated to avoid the roots drying out.
Tuber processing
To prevent problems with planting material, tubers must be treated before planting for vernalization.
The following types of chemicals are used to treat tubers:
- Fungicides;
- Growth stimulants;
- Nutrients;
- Insecticides;
- Disinfectants.
Fungicide treatment must be carried out if the potatoes were grown in the rainy season or purchased at the market. Wet weather promotes the spread of fungal spores.It is often not obvious from the appearance of the tuber that it is affected by a fungal infection; the first signs of infection appear during the growing season.
Purchased from an unknown manufacturer, seed potatoes may contain many pathogens that will not only affect the potato harvest, but may also contaminate the soil.
In this case, before storing for vernalization, the potatoes are thoroughly washed with disinfectants, being careful not to damage the skin. After washing the potatoes, soak them or spray them with fungicides according to the instructions.
Growth stimulants make it possible to reduce the time of vernalization and potato cultivation by 1 - 2 weeks. As a rule, they contain phytohormones identical to natural ones, which promote rapid development and good yield.
Treatment with potassium preparations before vernalization makes it possible to compensate for the deficiency of nutrients in the tuber. Potatoes develop faster and have good stress resistance.
It is very important to treat the tubers against harmful insects, especially if there have been cases of fall armyworm, wireworm or other pests in neighboring areas. Potato tubers may contain insect larvae.
Conclusion
Vernalization of tubers before planting does not require much time and effort. By choosing the appropriate method, you can significantly improve potato yields and reduce growing time.
