Preparation and selection of optimal soil mixtures for vegetable seedlings

Recipes and Preparation of Soil Mixtures

High-quality soil for transplants must contain easily accessible nutrients and be completely free of pests and disease pathogens. The composition of the soil mixture directly depends on local resources. In the Non-Chernozem zone, peat serves as the basis for the substrate, whereas in southern regions, humus and sod soil are more frequently used.

An optimal mixture, suitable for growing transplants of all vegetable crops, is obtained by combining equal volumes of peat and soil. To do this, mix moist, loose peat with a humidity of about 80% with either sod soil or manure-soil compost. To provide young plants with nourishment, the resulting substrate is enriched with mineral fertilizers calculated per 1 m³ of the mixture.

• Ammonium phosphate — 0.85 kg
• Potassium sulfate — 0.5 kg
• Potassium nitrate — ~0.25 kg

Before mixing peat with soil or compost, it must be deacidified. Liming fertilizers are used for this, with dolomitic flour being the best choice. The application rate of the flour depends on the type of peat: 2 kg/m³ is required for high-moor peat, 1.5 kg/m³ for transitional peat, and 1 kg/m³ for low-moor peat. The preparation "Izvest-Gumi" can also be used as a soil conditioner.

If preparing the soil independently is not an option, ready-made chernozem soils from the "Zemlya-Matushka" series are used. They contain peat, are enriched with "Khozyain-Batyushka" humus fertilizer and light ceramic loosening agents to improve structure, and are also sanitized with beneficial microflora and the biological products Fitosporin and Gumi. The product line offers specialized formulations with varying levels of nutrients.

Each type of soil is designed for the needs of specific crops. "Violet-Geranium" is optimal for violets, geraniums, gloxinias, fuchsias, and hyacinths. The "Lemon-Mandarin", "Ficus-Palm", "Cactus-Aloe", and "Lianas" formulations are created specifically for their corresponding groups of plants. The fully prepared "Floral Universal" soil is balanced for planting and transplanting any houseplants and flowers.

Verifying Soil Suitability Using a Bio-test

The simplest and most reliable way to assess the quality of a prepared or purchased mixture before sowing is to check it by seed germination. By comparing the dynamics of emergence in the test soil versus on clean filter paper, one can timely detect the presence of harmful substances. Such a test will save an entire batch of transplants in a greenhouse from perishing.

To conduct a bio-test, you will need 9 cm diameter Petri dishes or small jars, and the analysis itself is performed according to a simple scheme.

1. Take a soil sample one day after watering it.
2. Prepare three dishes with the test mixture, filling them with a 5 mm layer of moist soil. As a control, prepare three dishes with filter paper moistened with distilled water.
3. Sow 20–50 radish seeds in each dish.
4. Cover the containers with lids to prevent moisture evaporation, label the variants, and place them in a dark spot with a temperature of +20…+25 °C.
5. Count the number of germinated seeds daily for 6 days across all three replicates for both the control and the test samples.

Based on the daily counts, the average germination percentage is determined for the entire observation period. Comparing these data allows for a clear assessment of the degree of substrate toxicity. For clarity, the results of the seed germination tests are summarized in a table.

To calculate the germination rate as a percentage of the control, the average value of the test variant is divided by the average value of the control and multiplied by 100%. For Soil 1, this figure is 13.8% (9 × 100 / 66), and for Soil 2, it is 87% (58 × 100 / 66). These calculations make it possible to predict the behavior of transplants under real-world growing conditions.