In order for the tomato plants to grow and thrive properly, the choice of the appropriate substrate is essential in the first place. Depending on the ripening process, tomatoes have different requirements for the soil, which must be met. In this article, read what you should look for when choosing a substrate and take away helpful tips that will make growing tomatoes much easier!
The right growing soil
Tomato plants belong to the group of so-called heavy growers, but during cultivation they have completely different conditions to the substrate, than adult specimens. This is because the roots of the seedlings can not cope with the excess of nutrient salts, which is why the plants can burn and even die. It is best for the seeds to germinate in soil that is as low in nutrients as possible. This is because the search for nutrients spurs the roots to grow. However, if the growing soil is already rich in nutrients, root growth can sometimes be inhibited because the nutrients they need are virtually “right in front of the root tip”. The optimal conditions for germination are obtained with the following substrates:
- Seed or growing soil
- a mixture of peat and sand in equal parts
- uniform soil of perlite, natural clay and white peat
- coco humus is suitable as a peat substitute
Make your own growing soil
Since the growing soil is usually expensive to buy, many amateur gardeners resort to the option of making it yourself. The main ingredient here is garden soil, which is mixed with sand and, if necessary, some compost. The garden soil can be taken from your own garden without any problems, but here it is important to make sure that the top layer of soil is not used. It is better to first dig a few centimeters deep or use the soil from a fresh molehill. The preparation of the growing soil is relatively simple and is as follows:
- Sift and sterilize garden soil
- then add sand, ideally quartz sand
- because this is angular and does not compact
- and also ensures good water drainage
- Add compost as follows: 1 part each of soil, sand and compost.
Tip: The mixing ratio depends primarily on the nutrient content of the soil. If the soil is low in nutrients, use 2 parts soil and 1 part sand. However, if the soil is nutrient rich, then the mixing ratio is 1:1.
Sterilizing the soil
Often the soil is infected by bacterial pathogens, insect eggs or fungal spores. This is not always visible to the naked eye and sometimes poses a threat to the health of the seedlings. Therefore, it is advisable to sterilize the growing soil before use and eliminate possible pathogens. Sterilizing the soil takes very little time and is relatively simple. Two different methods have proven successful for this purpose:
- Put the substrate in a fireproof container
- in the oven at 150 degrees top and bottom heat for about 30 minutes
- in the microwave at 800 watts for about 10 minutes
Substrate after pricking out
When pricking out the young plants are placed in their own pots, so that they have enough space for further development. Since from this point on the focus is increasingly on the growth of the plants, the substrate may accordingly be somewhat more nutritious. For example, the following substrates are suitable for the young plants:
- Commercially available vegetable soil
- however, this should be leached with peat, sand or perlite
- ideally in a ratio of 1:2
- or special uniform potting soil
- which has a proportion of green waste compost
Tip: You can easily make the potting soil yourself: For this, coconut fiber or perlite (about 40%), compost (25%), garden soil (15%), bark humus (10%) and sand (10%) are mixed.
The optimal soil until harvest
Since tomatoes are heavy eaters, a nutrient-rich soil is essential. In addition, the soil should be loose, because this ensures good soil aeration and good water drainage. Furthermore, the roots can develop best in a loose soil. Ideally, the substrate is also humus-rich and has no coarse components such as pieces of bark or plant debris. However, nutrient-poor soils can also be used for tomato plants by enriching them accordingly with fertilizers. For this purpose are particularly suitable:
- Garden compost
- Horn shavings
- Horn meal
Tips for tomato soil in the open field
For the culture in the tub can be purchased special tomato soil, whereas in the open field must be worked with the existing soils. The soil in the garden does not always provide the optimal conditions for tomato plants, although these can often be created with simple steps. First and foremost, the soil should be continuously supplied with trace minerals, for this purpose, for example, primary rock flour is suitable, which is worked into the soil. To meet the nutritional needs of tomatoes, it is also advisable to supply the soil with an organic fertilizer. In addition, there is the possibility of “working” the soil – depending on its condition – optimal for tomato plants:
- work into loamy soils so-called aggregates.
- for example, sand or fine-grained lava chippings are suitable for this purpose
- this provides a better soil structure
- loosen” sandy soils
- so that water and air can penetrate and circulate better
- Betonite and zeolite are suitable for this purpose
The optimal pH value of the soil
The alkalinity (acid binding capacity) of the soil is measured by its pH, where a pH of 7 is considered neutral. If the value is lower, the soil is acidic; if the value is higher, it is alkaline. Tomatoes grow best in a slightly acidic to almost neutral soil, so the pH of the substrate should have a value of 6 to 7. However, the optimal pH of the soil is between 6.5 and 7, so if you want to get the best results from the tomato harvest, you should measure the pH of the soil every three to five years and adjust it if necessary. The following are some possible ways to do this:
- Increase the pH value by working lime into the soil.
- ground agricultural lime, for example, is suitable for this purpose.
- Reduce the pH value by working sulfur into the soil.
- a fertilizer containing ammonium sulfate, for example, is suitable for this purpose.
- This is what the tomato soil should contain
Tomato plants need a sufficient amount of nutrients on an ongoing basis to grow and thrive. Many high-quality substrates already contain a solid mixture of all nutrients, yet the addition of fertilizer is usually not necessary. Therefore, to achieve the best possible results from tomato crops, it is essential to provide adequate nutrients. Tomato plants need the following nutrients in particular:
- Nitrogen for plant growth
- Phosphorus for flower and fruit formation
- this also helps to develop strong root systems
- and build disease resistance
- potassium protects against diseases and cold
- various trace elements
- such as zinc, copper, iron, manganese and boron
- Low-quality soil vs. high-quality soil
Especially for cultivation in tubs, it is advisable to use high-quality soil. Because low-quality substrates usually consist of peat, these are treated with lime and low-quality mineral fertilizers. You can also use these (without problems), but the tomato plants are usually more susceptible to disease. In addition, the savings on the purchase of a low-quality tomato soil is usually not worth it, because the tomato plants usually require more fertilizer and pesticides further down the line. Therefore, it is advisable to invest in a high-quality tomato soil, which at best contains the following additives:
- Clay components
- humus substances (for example, bark humus)
- ideally, it contains an organic slow-release fertilizer