Feeding tomatoes with ash


Any experienced gardener would agree with the fact that in order to get good yields of tomatoes, they necessarily need a variety of top dressing. It would seem that in stores and on the Internet now you can find fertilizers for every taste and budget. They can be mineral or organic, or even complex, including a variety of growth and development stimulants. But for some reason, like hundreds of years before that, common ash is still popular as a top dressing of tomatoes.

Not for nothing, probably, most gardeners prefer to fertilize their tomatoes with ashes, because the quality of its components can be traced personally by yourself, while no one will tell you exactly what was used to make these or other mineral fertilizers.

Ash, its composition and types

Ash obtained by burning various organic materials has been used as a fertilizer for plants for a very long time.

Comment! The exact chemical composition of this substance is difficult to determine, since it is constantly changing and depends on both the organic species and the age of the plants that were burned.

However, as early as the 19th century, an approximate formula was derived, which indicated the approximate ratio of various substances found in the composition of 100 grams of wood ash.

This formula is very valuable for understanding what is the real value of ash, as fertilizer for tomatoes. Since different substances may be responsible for different processes in the life of plants, in this case tomatoes. Some are able to accelerate growth and development, others help in the fight against diseases, and others improve the quality of the fruit.

The composition of wood ash:

  • Calcium carbonate -17%;
  • Calcium silicate - 16.5%;
  • Sodium orthophosphate - 15%;
  • Calcium sulfate - 14%;
  • Potassium orthophosphate - 13%;
  • Calcium chloride - 12%;
  • Magnesium carbonate - 4%;
  • Magnesium sulfate - 4%;
  • Magnesium silicate - 4%;
  • Sodium Chloride (Rock Salt) - 0.5%.
Attention! If we analyze the above formula, it becomes clear that in the composition of wood ash calcium takes the main place among all other elements.

Calcium and the role of its salts

Calcium is necessary for tomatoes throughout the growing season, its presence is important for the normal growth of the seedlings and it helps to ensure balanced nutrition of the tomato bushes until the very end of fruiting.

Calcium carbonate is able to enhance the speed of movement of various substances in plant cells and normalize the course of biochemical processes. Thus, when using wood ash, as a fertilizer for tomatoes, active growth and accelerated ripening of tomatoes is observed.

Calcium silicate helps the active absorption of vitamins from the soil and other materials used for fertilizing. In addition, this substance, when combined with pectins, can glue cells together, keeping them together. This salt when using ash for dressing tomatoes can help saturate the fruit with vitamins.

Calcium sulfate is usually included in the composition of superphosphate, which is one of the most popular mineral fertilizers. Moreover, when feeding tomatoes in the composition of the ash, it has not so strong, but it has a more lasting effect on the tomato bushes than when it is in the composition of the mineral fertilizer.

Calcium chloride

Despite the fact that in many sources the presence of chlorine in wood ash is denied, this statement is not true. In fact, a small amount of chlorine is necessary for the normal development of the tomato. To begin at least with the fact that the green mass of tomato plants constantly contain at least 1% of chlorine of its total weight. Calcium chloride is able to activate the formation of enzymes and positively influence photosynthesis.

Important! Calcium chloride has a remarkable property of “draining” the effect on the soil.

Thanks to this, ash can be used to combat many diseases caused by stem and root rot, as well as for the healing of the earth.

Interestingly, the presence of calcium chloride in the soil also allows ammonium nitrate to be converted to the nitric acid salt, which plays a decisive role in the development of plants. Thus, although ash does not contain nitrogen in its composition, but using it as a feed for tomatoes allows you to additionally supply tomatoes and a certain amount of active nitrogen.

Potassium and phosphorus

These two elements are found in ash in smaller volumes than calcium, but in sufficient quantities to normalize the metabolic processes in tomato plants.

Potassium orthophosphate is able to help in the regulation of the water balance of plants. If this substance is insufficient in tomatoes, then ammonia will accumulate in the roots and leaves, which inhibits plant growth. Potassium is also responsible for the abundant flowering and fruiting of tomatoes. And phosphorus directly affects the work of the roots.

Sodium orthophosphate is particularly useful for tomatoes, since they can be attributed to sodium aphids, that is, plants that respond positively to the presence of sodium, especially in conditions where there is insufficient potassium availability. In addition, sodium orthophosphate is able to activate some enzymes that do not react with other substances from the ash composition.


The composition of wood ash consists of three magnesium compounds. In general, magnesium is part of chlorophyll and is a member of plant photosynthesis. Magnesium usually acts as a “companion” of potassium, the two of them are involved in the production of energy by plants.

Magnesium sulfate, in addition, is involved in the formation of carbohydrates, which become "building blocks" for the formation of cellulose and starch.

Lack of magnesium causes a slowdown in the growth of tomatoes, a delay in flowering, tomatoes do not ripen.

Ash varieties

Above was given the formula of the approximate composition of wood ash. But besides her, for feeding tomatoes, you can use other types of ash, obtained by burning various organic materials. Their composition will vary slightly among themselves. The table below shows the approximate content of the main nutrients, depending on the types of ash. This information can be useful for choosing the optimal feeding for tomatoes in your conditions.


Content of main elements in%




Leafy trees




Coniferous trees








Straw Cereal

4 - 8

4,0 - 8,0

10,0 - 20,0

Buckwheat straw



30,0 - 35,0

Sunflower stalks

18 - 19


36,0 - 40,0


65 - 80

0,5 - 1,5

1,0 - 1,5

For example, if you are interested in the maximum potassium content in the ashes, then instead of firewood it is necessary to burn a certain amount of stalks of sunflower or buckwheat straw.

Ways to use ash

How can ash be used as a top dressing for tomatoes? There are several ways, each of which is good in its own way.

Use of dry ash

The easiest way is to add ash to the ground:

  • In the manufacture of land mixture for seedlings;
  • When planting seedlings in the ground;
  • For sprinkling around the bushes tomato during fruiting.
Tip! When you prepare the soil for growing tomato seedlings for every liter of land, you can add a tablespoon of sifted ash and stir well.

This will help loosen the ground, provide additional protection against fungal diseases and, of course, provide sprouts with basic nutrients.

During the planting of seedlings of tomatoes in the ground, you can either pre-add ash to the soil (in the amount of about 200 g per 1 sq. Meter), or pour it into each well during planting (about two tablespoons of the substance are spent on one bush).

During the flowering of tomatoes, as well as during the fruiting period, you can regularly feed the tomatoes, sprinkling the ground around the bushes with ashes. This procedure should be carried out after rain or abundant watering, every two weeks, using about 50 g under a bush. This dressing will help make the tomatoes sweet and provide them with health and strength of growth.

Finally, the ashes of the plants themselves are used to repel pests and diseases. It will be most effective to mix the ashes with tobacco dust in equal proportions and several times to powder the tomato bushes with this mixture. The procedure should be carried out in calm weather, and in greenhouses, you can simply close all doors and windows. The tool works well against the larvae of the Colorado beetles, slugs and cruciferous flea.

Cooking ash solution

Ash, as a fertilizer for tomatoes, is most often used in the form of ash solution. It is used mainly for periodic feeding of already grown tomato bushes. Cook it easy enough. In ten liters of water at room temperature dilute 100 grams of ash, insist for several hours and pour the tomato bushes under the root with the resulting solution. For one bush enough to use about half a liter of ash solution.

Tip! Even tomato seeds can be soaked in the ash solution before sowing, which helps to improve their germination and speed up germination.

Only the concentration of the solution will be slightly different. First, the ash must be carefully sifted to get rid of excess impurities. Then in two liters of hot water it is necessary to dilute 1 tablespoon with the top of the ash and insist in a warm place during the day. After the solution must be filtered and it is ready. It is possible to soak tomato seeds for several hours, and you can water young sprouts when the first two true leaves appear.

After watering tomatoes with an ash solution, the effect of it in the form of activating plant growth is observed in a week. The solution for foliar feeding with ash acts even faster, while preparing it is somewhat more difficult. It is necessary to take 300 grams of carefully sifted ash and dissolve in three liters of water. The resulting mixture should be boiled for 30 minutes. Then water is added to it, so that the total volume is 10 liters. About 50 g of laundry soap are added to the diluted mixture and allowed to brew for about a day. With this mixture it is good to spray tomato bushes for first aid if there is a shortage of nutrients or to scare away pests, for example, aphids.

Tip! To improve the taste of tomatoes, complex supplements are sometimes used with the use of ash solution.

To prepare them, pour two glasses of ash with two liters of hot water, leave for two days and strain. To the resulting infusion add 10 g of boric acid, 10 g of iodine, dilute the mixture 10 times and the resulting solution is sprayed tomato bushes during flowering.

Herbal tea

Very often, ash is used in dressing tomatoes with “herbal tea”. First, collect a variety of herbs that grow on the site and nearby: dandelion, clover, nettle, snyt, plantain and others. With prepared herbs, any container is на of its volume, filled with water and covered with a lid. In this form, herbs are drawn for about a week. When a characteristic odor appears, about 300 grams of ash is poured into the container and everything is thoroughly mixed. One liter of the resulting infusion is added to a bucket of water and tomato bushes are poured with this mixture. In this fertilizer, as a rule, almost the entire periodic table is in a well-digestible form for plants.


Ash is the most affordable type of fertilizer for gardeners. And given its organic origin and versatility in use, it is not surprising that for many years it has not lost its popularity with anyone who, one way or another, is associated with the earth.