How and when to fertilize tomatoes

One of the most important vegetables is undoubtedly the tomato , undisputed protagonist of our gardens during the spring-summer season. Having beautiful tomatoes is a source of great pride for the grower and the amount of substances present in the soil obviously plays an important role in this.

Tomato cultivation has a long cycle, which begins in April-May with transplanting, or even earlier with sowing in the nursery, until September-October when the exhausted plants will be eradicated. In this vast period the plant is quite demanding in terms of substances.

To obtain a good production from start to finish, fertilization is one of the decisive factors, together with disease prevention and pest control, which guarantee the health of the plant at all times.

Contents [Ocultar]

• How to fertilize in organic farming

• Basic fertilization for tomatoes

  • Period and function of rotations

• What the tomato plant needs

  • Fertilization at planting

  • Fertilization in the graft

  • During growth phases

• Fertilization and irrigation

• Recognize gaps and act

How to fertilize in organic farming

In the organic cultivation of tomatoes, as in other crops, fertilizing is not imposed on the basis of a calculation of the amount of elements necessary for the vegetable, but a fundamentally different approach is applied. Think about making the soil pleasant, making it rich in life and organic matter, and therefore in fertile soil in all respects (microbiological, physical and chemical) lush and healthy tomatoes can grow.

Of course, in addition to a general rule, there are unique aspects to each land, so it is necessary to know the characteristics of the garden that we cultivate. It is always useful to have an analysis carried out by a professional laboratory, which can indicate any specific need.

Even though you usually fertilize to take care of the soil anyway, it pays to take a few precautions about the vegetable you want to grow. In this article, we see in particular how and when to fertilize the tomato, the undisputed protagonist of our orchards in the spring-summer season.

Basic fertilization for tomatoes

The tomato is a demanding plant, which requires a good content of organic matter. This must be taken into account when preparing the bottom fertilization, which is what affects the plot before transplanting the crop and which is carried out in parallel with the shovel. Land used for tomatoes should be prepared very carefully, both in terms of deep tillage and fertilization. .

During tillage, the soil is distributed the soil conditioner , which can be compost or manure from various animals (cows, horses, sheep, pigs), must in any case be well ripe, that is, not fresh but left to rest in a heap for a few months. Compost or manure that is still maturing would indeed continue the transformation process in the soil and this would damage the roots of the growing plant, if it matures it is more stable and therefore healthy. Regarding the amount of manure, about 4-5 kg ​​per square meter is enough, usually a wheelbarrow contains about 25-30 kg. . Therefore, we can calculate the fertilizer carts according to the area to be fertilized.

It is good to remember that if instead of manure or fertilizer we have manure, it will be necessary to reduce the doses because it is richer, it contains for example 3-4% of nitrogen against 1-2% of dry cattle manure, as well as 3 to 5% phosphorus and 2 to 3% potassium.

Ultimately, the soil amendment should not be shoveled deeply : it must remain at most in the first 30 cm of soil, that is to say the most explored by the root systems, although some tomato roots even reach 1.5 meters deep. But it is especially in the first layers of the soil that we find oxygen, essential to the micro-organisms which mineralize the organic substance to give nutrients to the plants. In addition, with rainwater and irrigation water, the elements are mobilized even deeper, towards the roots below.

Period and function of rotations

The best time to work and amend the soil is in the fall. , but the ground is not always free in this season, on the contrary, with reason why there are usually autumn-winter crops in the garden. Therefore, for the fertilization of tomatoes, it is also necessary to take into account the species previously present in this space. A typical situation might be that there were cabbages until January, then spinach Until April.

In this case the soil has been well exploited and therefore before putting the tomato plants in addition to the soil amendment, one should add granulated manure, about 300 grams/m², handfuls of wood ash, if available, which contains potassium and calcium, and also rock flour, which is rich in microelements or seaweed flour ( lithotamnium), also rich in calcium.

If, on the other hand, as it is recommended to do at least in some flowerbeds, a mixture of green manure had been sown in autumn, the burial of the biomass takes place about a month before the transplanting of the tomato, and this green fertilization replaces the first composting.

What the tomato plant needs

The tomato needs to be nourished during all the phases of its growth .

In particular, nitrogen It is used during the vegetative phase for the elongation and strengthening of the stem and for the formation of leaves and flowers. Then flowering and fruiting are favored by potassium, an element that governs the color of berries and their sugar content, but also the resistance of plants to adversity. Phosphorus is necessary for the ripening of fruits and seeds. These elements are those that are needed in greater quantities and, together with those that are needed in smaller quantities (magnesium, sulfur, calcium, but also iron, copper, etc.), are normally found in the ground and also in the air conditioner , the soil and the natural fertilizers that are provided.

Therefore, it is advisable to see at each stage of the growth cycle how we can help the plant through proper fertilization.

seed fertilization

Planting seedlings in nurseries normally does not require separate fertilization. Initially the seedlings grow thanks to the reserves contained in the seed itself then for the first stages a good specific soil for sowing is enough to guarantee them what they need until the moment of transplanting in the garden.

graft fertilization

When transplanting, if we have not done it yet, it is useful to add a little natural fertilizer as described above, since it must be taken into account that the tomato is a long-cycle crop, it will remain in this soil until September and require prolonged feeding.

The most important thing is that these fertilizers must be spread by handfuls over the entire surface dedicated to the tomato: avoid putting it only in the transplant holes because it would be a useless gesture: the roots would then expand and the food contained in this small volume of soil would not be available to them.

During growth phases

If in the transplant we distributed granulated manure, during the summer it is better to add a few handfuls with irrigations with macerations of plants such as nettle and consolidated nettle which will be more or less every two weeks.

In summer the plants produce and with the harvest we remove substances.

Fertilization and irrigation

Nutrients for the plant are transported by water, rain or irrigation. Therefore, prolonged drought is not positive, both because of the limitation of chlorophyll photosynthesis and because of the reduced absorption of nutrients, even if they are present in the soil.

Irrigation should be regular and, if possible, administered with a drip system, which allows good penetration of water into the soil and absorption without residues.

Mulch saves irrigation water and, if made with organic matter, adds extra organic matter to the soil, which, as is always said, is essential for soil fertility. , regardless of the culture it hosts.

Recognize gaps and act

Deficiencies of certain nutrients give specific symptoms : For example, a nitrogen deficiency results in a pale green color of the leaves and a limited growth of the stems; Potassium deficiency can be recognized by darkening of leaf edges, while with phosphorus deficiency leaves may appear purple and small, with poor flowering and production. The lack of magnesium, on the other hand, manifests itself in the particular yellowing of the leaves, where the inner veins remain green.

A typical pathophysiology that tomato shows in the fruit is blossom end rot, also known as “black ass”. It is not a fungus but a water imbalance that prevents the proper transport of calcium. Calcium can be transported naturally by spreading wood ashes directly on the ground or by adding them to the compost pile. The ashes contain more than 30% calcium. But the irrigation must also be balanced to avoid this problem.

But let’s not forget that overfertilization is at least as detrimental as deficiencies . As for nitrogen, if it is excessive, it leads to vegetative exuberance which delays fruiting and exposes the plants to aphids and fungal diseases, as well as to the risk of contamination of groundwater by nitrates. Therefore, the nutrient dose of natural fertilizers should not be underestimated and, therefore, should never be dispensed in excessive amounts .