If you continually grow the same crops in greenhouses, soil health will deteriorate. Plants take away useful elements, the soil accumulates harmful substances, and pathogenic microorganisms appear and multiply in it. To increase the fertility and quality of the soil, alternate crops annually, apply fertilizers and structure-forming agents (sawdust, straw, sand, perlite), and wash the soil. But due to the small area of the greenhouse, such measures do not always give the expected result. Only high-quality replacement of soil can radically solve the problem.
Why do you need to change the soil in a greenhouse?
Soil depletion. Most often, monocultures are grown in greenhouses, which actively absorb nutrients. The soil loses its ability to regenerate itself if you do not apply crop rotation rules when growing crops. As a result, the soil in your greenhouse is depleted so much that even if you start fertilizing, it doesn’t help much. In addition, weeds deplete the soil even more.
Please note! In poor soil, plants experience a lack of nutrients and begin to “starve”. As a result, they grow slowly or stop growing altogether, and there is a delay in flowering and fruit set. With a deficiency of phosphorus, the leaf blades acquire a purple tint, lack of potassium, the leaves look burnt. If the plants lack nitrogen, the stems become elongated.
Soil poisoning. As a result of fertilizing, the use of herbicides, insecticides and fungicides, greenhouse soil accumulates harmful substances – the remains of undecomposed fertilizers (sulfur, chlorine, ammonia) and heavy metals. Therefore, the grown vegetables will not be environmentally friendly due to the increased concentration of nitrates.
Soil salinization. Due to the lack of a “flushing regime,” the greenhouse soil gradually accumulates salts, which becomes the cause of its salinization. Often a similar situation occurs when using purchased soil mixture.
Soil contamination. Due to poor crop rotation and insufficient soil freezing, larvae of harmful insects, spores of pathogenic fungi, viruses and pathogenic bacteria accumulate in the greenhouse, which leads to the development of various diseases. Pathogens can also be introduced through seedlings, seeds, shoes and clothing. As a result, planted plants often get sick and develop slowly, dying from pests.
Compaction of the earth. Over time, the soil loses its nutritional properties, loses its ability to pass water and air, and becomes compacted. As a result, the roots remain in the surface layers, since they cannot penetrate deeper, the plants begin to get sick, grow poorly, and the yield is significantly reduced.
Change in soil acidity. With a lack of certain elements, the soil acquires a pronounced acidic or alkaline reaction, which leads to inhibition and sometimes death of plants.
Deterioration of soil structure. In the absence of a sufficient amount of humus, the acidity of the soil changes, its ability to pass air and retain water. As a result, plants cannot develop and bear fruit normally.
By replacing the soil, it is possible to improve its structure, increase fertility, destroy pest larvae, get rid of infections, and, consequently, improve the growth of cultivated plants and significantly increase productivity.
Main signs that it’s time to change the soil in the greenhouse
A radical replacement of soil in a greenhouse is necessary when:
- deterioration of soil fertility;
- slowing down plant growth;
- strong proliferation of pests;
- frequent infections (fungal, bacterial, viral).
When is it better to change the soil
You should keep the humidity in your greenhouse low and the temperature between 50-60 °F (10-15 °C) during this procedure. In this case, the result will be as effective as possible.
How often to change the soil
The frequency of replacement depends on the plants being grown. The most finicky ones are cucumbers and tomatoes. Therefore, they should replace the substrate every 2-3 years. Green and root crops can be grown in the same soil for much longer.
Please note! In addition to periodically replacing the soil, it is necessary to revitalize it annually.
How to replace soil in a greenhouse
It is important to select and replace the soil correctly. Otherwise, the new soil may be of poor quality, and pathogens and pests will survive.
Soil replacement is carried out in stages:
- remove weeds and remains of cultivated plants;
- thoroughly wash the roof and walls of the greenhouse with soapy water;
- remove the top layer of soil 10-15 centimeters thick (for severe lesions, 20-30 centimeters should be removed);
- the soil substrate is scattered over the entire area of the greenhouse;
- the ground is disinfected by watering with a solution of copper sulfate (20 grams per bucket of water), Bordeaux mixture or potassium permanganate, or sprinkled with bleach (4 kg per 1 m3);
- if desired, additionally water the soil with a special solution with beneficial microflora;
- apply fertilizers (taking into account the crops planned for planting);
- digging up the ground.
Crop rotation or which plants after which to grow in the garden
To prepare universal soil for a greenhouse, mix coarse river sand, rotted compost or humus, turf soil and peat in a ratio of 1:2:3:4.
If possible, the nutrient substrate is selected depending on the crop:
- cucumbers – 2 parts of garden soil, one part each of sawdust, manure and peat;
- tomatoes – 2 parts of garden soil, one part of river sand;
- pepper – 2 parts of garden soil, one part each of humus and river sand;
- root vegetables – 2 parts garden soil, 1.5 parts river sand, one part humus;
- cabbage – 2 parts garden soil, one part compost or humus.
If there is no time and desire to prepare the soil mixture, you can use purchased soil.
How to Renew Soil Health
To restore the nutritional properties of depleted soil, you should fold it in layers along with mowed grass, sawdust and manure, add mineral fertilizers and bleach, and water with a solution of copper sulfate. Keep your compost moist. Under these conditions, beneficial bacteria will begin to defrost and do their job. They say that compost “burns” – the temperature inside the pile will increase noticeably. After 1-2 years, the soil will be disinfected and enriched with useful substances, becoming suitable for further use.
Otherwise, you can plant unpretentious plants or crops in the used soil, with which greenhouse vegetables do not have common pests and diseases.
