Useful Tips

Features of potassium nitrate for plant fertilizer


origin of name

First, let's talk about its name. Nitrate is any salt that has an acidic NO3 residue taken from nitric acid, i.e. is nitrate. The chemical formula of nitrate being discussed is KNO3, which means that the adjective "potassium" must be added to its name. But there are other options for writing it. In various sources, it can be called potassium / Indian nitrate, potassium nitrate, potassium nitrate, etc. All of these names will be correct.

The properties

Under normal conditions, this nitrate is colorless crystals, but crushed it resembles a white powder. It also has an ionic structure and a hexagonal or rhombic crystal lattice. Potassium nitrate is slightly hygroscopic, prone to slightly caking for some time. It is also non-volatile and odorless. It dissolves well in water, to a moderate degree in liquid ammonia, glycerin, hydrazine, does not dissolve in pure ether and ethanol (it can dissolve poorly only if the latter are diluted with water). Needle and very long crystals can grow from potassium nitrate during its slow crystallization. At a temperature of 400-520 ° C, its decomposition occurs, at which potassium nitrite and oxygen are formed.


In the Middle Ages and the New Age (i.e., during the period when gunpowder was in frequent use), potassium nitrate was extracted from saltpeters - heaps consisting of limestone materials, manure and other decaying components that had layers of brushwood or straw. They were covered with turf holding the gases formed. Ammonia, which was formed due to rotting of manure, accumulated in the layers, nitrified, and became first nitrous, and then nitric acid. The latter, when interacting with limestone, formed calcium nitrate, then it was leached with water. When wood ash was added to this mixture, the calcium carbonate in the former settled. And the result was a solution of potassium nitrate. The interaction of potash and calcium nitrate is the oldest way to obtain potassium nitrate, which is still popular. Although potash can be replaced with potassium sulfate. Potassium nitrate can be obtained in the laboratory with the following reactions:

  • Potassium Chloride and Sodium Nitrate.
  • Ammonium nitrate and potassium chloride.
  • Potassium hydroxide and nitric acid.
  • Potassium and nitric acid.
  • The corresponding alkaline potassium oxide (K2O) and the corresponding acid (nitric).
  • Potassium hydroxide and nitric oxide (5).
  • Ammonium nitrate and potassium hydroxide.
  • Potassium carbonate and nitric acid.

Being in nature

In nature, potassium nitrate is known as the mineral nitrocalite. The largest deposits are Chile and the East Indies (which is why potassium nitrate is often called Indian). Natural potassium nitrate is a nitrogen bacteria associated with ammonia, which is released during the decomposition of nitrogenous substances. Moisture and heat contribute to this relationship, which is why the largest deposits of potassium nitrate are in hot countries. Also in very small quantities, it is present in animals and plants.

It is mainly used as a valuable fertilizer for plants (photo). It is also a very important ingredient in the composition of smoke powder ("smoke", smoke bombs). This nitrate is also useful in optical glassmaking, by bleaching and brightening technical crystal glasses and giving strength to glass products. In the food industry, this nitrate is known as the preservative E252.


Potassium nitrate (KNO3 formula) can be used not only in chemistry, but also in many other industries. It can be both useful and very harmful to humans.

The composition of potassium nitrate

Potassium (potassium) nitrate is a potash-nitrogen feeding of cultivated plants, which is suitable for all types of soil. Nitrate contributes to the vital activity of plants from the very moment of planting. Fertilizers enhance natural processes: root intake of nutrients from the soil, respiration and photosynthesis, and disease resistance.

Under natural conditions, potassium nitrate is a colorless crystal, which upon grinding becomes a white crystalline powder. It can cake, but the chemical properties do not change. In any form, potassium nitrate has good hygroscopicity: it is easily soluble in water, which allows you to make solutions for feeding different types of plants in the garden. Potassium nitrate can be dissolved in glycerol, liquid ammonia and hydrazine. The substance is non-toxic.

The beneficial effect of potassium nitrate on plants is due to its composition. The substance contains two main components: potassium and nitrogen. A feature of this mineral fertilizer is a small amount of nitrogen (13% versus 44% potassium).

The predominance of potassium in this type of nitrate allows the use of fertilizer even after flowering and ovary formation. There is enough nitrogen to strengthen the plant, but not enough to activate the growth of green mass. Potassium fertilizer at the flowering and ovary stage will contribute to the development of the future crop, improve the taste of berries and fruits.

Useful properties of potassium nitrate

For full-fledged plant growth, recharge is needed, especially with the meager characteristics of the soil. Fertilizers with potassium strengthen plants, increasing their resistance to drought and frost, contribute to the formation of buds on flowering shoots.

Exposure to potassium nitrate:

  • accelerated plant growth,
  • improved cellular respiration,
  • activation of immunity,
  • disease protection
  • yield increase
  • increased absorption of roots,
  • increased fruit
  • frost resistance increase,
  • increase shelf life
  • improvement of taste.

The use of potassium nitrate

Potassium nitrate is intended for root and foliar feeding. The greatest efficiency is observed when fertilizing root crops (like carrots and beets), tomatoes, raspberries, blackberries, currants, and flower and ornamental plants. Potassium is also useful for the growth of fruit trees. Potassium nitrate almost does not contain chlorine, so it can be applied to plants that do not perceive it (grapes, tobacco).

Very often, fertilizer is used during the ripening period of cucumbers. It will inhibit the growth of greenery and increase the size of the fruit. Since these vegetables ripen unevenly, part of the nitrate is spent on the formation of set cucumbers.

It is not recommended to use potassium nitrate on cabbage, herbs and radish. It is noteworthy that for feeding potatoes it is better to use phosphorus, nitrate in this case gives few results.

Potassium nitrate significantly enhances the taste and improves the quality of the crop. The pulp is saturated with fruit sugars, the fruits are larger than standard. If fertilizer is applied at the ovary stage, the shelf life of the fruits increases due to the improvement of their keeping quality.

Using potassium nitrate is very simple. In stores, fertilizer is sold in optimal dosages. For a small household plot, you can buy small packages of 1-5 kg, and for large farms, industrial agronomy or vegetable farms - packing of 20-50 kg.

It is recommended to breed potassium nitrate only in water. Do not mix the substance with organic fertilizers, that is, with peat, sawdust, compost, manure and straw. It is not recommended to abuse watering with potassium nitrate, usually two supplements for the summer are usually enough.

More than four baits per season will contribute to the accumulation of nitrates in vegetables. To avoid this, you need to water after using nitrate. It is rational to do complementary foods in the rainy season.

Proportions and frequency of feeding

Fertilizer with potassium is allowed to be applied under shoots in both dry and liquid form. Since the solution has a quick action, it is used more often.

  1. Floriculture, ornamental plants: 15 g per 10 liters of water.
  2. Currants, blackberries, gooseberries, raspberries and blueberries: 20 g per 10 liters.
  3. Fruit trees: 25 g per 10 liters.

Such proportions are most rational when applying fertilizer either under the root of the plant, or in the trunk circle, or in the hole. If foliar top dressing is planned, it is better to use a more concentrated solution, since part of the potassium nitrate will evaporate from the leaves and will be washed off with water when watering. In this case, you need to make the maximum concentration (25 g per 10 l). Flowers, ornamental plants and wild strawberries should be sprayed in an amount of 0.7 liters per m 2, shrubs with berries - 1 liter per 1 m 2, fruit trees - 1.5-7 liters. Spraying trees, you need to take into account their age and density of crowns.

During the summer period, 2-4 sprayings can be made. Fertilize for the last time you need a month before harvesting. If it was not possible to calculate the timing correctly, and the fruits ripened early, it is necessary to drench it abundantly with water 10 days before removal using a hose with a sprayer. Repeat three times (every other day), the last watering should be done 3 days before harvesting. Pour the crop carefully so as not to bring down the berries and fruits.

Feeding cucumbers and tomatoes

Potassium nitrate is considered the best for feeding cucumbers and tomatoes. Fertilizer helps to accelerate the processes of photosynthesis, strengthen the roots and increase productivity. Usually use liquid nitrate to fertilize these plants. The solution can be purchased ready-made or prepared independently.

To process cucumbers, a solution prepared from 25 g of saltpeter per 15 liters of water is used. This is enough for a single feeding of a large greenhouse at the initial stage of the growing season. Tomatoes are fertilized with a similar solution, but they carry out radical top dressing. 0.7-1 l of saltpeter is poured under the bush (15 liters is enough for 15-20 pieces). Basal top dressing is carried out during the flowering period.

Potassium nitrate can also be used to fertilize seedlings. Tomato seedlings are watered with a liquid solution when 3-4 leaves appear, or before planting seedlings in the ground (per week). Liquid potassium fertilizer can be used during the dive seedlings.

Fertilizing cucumbers and tomatoes is best during the rainy season. Saltpeter will help protect against diseases, because in the rainy summer, cucumbers often infect scab and increase the tendency of tomatoes to late blight.

Fertilizing root crops

Fertilize root vegetables better with dry potassium nitrate. Potassium nitrate is introduced into the soil before planting when digging the soil (50 g per m 2). Root crops contribute a few days after top dressing.

To fertilize cabbage and potatoes, you can combine fertilizers: potassium and calcium for cabbage, potassium and phosphorus for potatoes. Carrots and beets are fertilized with pure potassium nitrate, but calcium is allowed.

Potassium Nitrate in Floriculture

Potassium nitrate can fertilize flower crops. The substance is introduced into the soil during the preparation of flower beds. Thus, the mineralization of the soil increases and its protection from insects is ensured.

Pure potassium nitrate is useful for rhododendrons, small-bulb flower crops (in this case it is recommended to mix with ash). In early spring, saltpeter is useful for feeding lilies, dahlias, tulips and gladioli. Clematis is enough to fertilize twice a season.

During budding, it is better to use a liquid solution. Nitrate can be useful for home begonias and violets.

Security measures

Before using potassium nitrate, read the instructions. Since concentrated nitrate pairs are unsafe for human health, safety measures must be observed. You can work with top dressing only in rubber gloves, and special glasses are used to protect the eyes. Use saltpeter in tight clothing and with a respirator.

If the solution gets on the skin, immediately wash it off with plenty of running water and treat the affected area with an antiseptic.

Since potassium nitrate is an oxidizing agent that interacts with combustible substances, it is stored in a closed container or tight bag. In no case should nitrate be left in a dangerous proximity to combustible or flammable substances. In places of storage of potassium fertilizers it is forbidden to smoke, children are not allowed there.

Fertilizing plants with potassium nitrate, you need to take care of their safety. To better absorb the solution and fill the lack of moisture, top dressing should be combined with watering. It is not recommended to abuse nitrate on acidic soils, since the fertilizer oxidizes the soil. Potassium nitrate can burn plants, so top dressing is done carefully, without getting on the stems and leaves (if the solution is highly concentrated).

Cooking potassium nitrate at home

You can make fertilizer with potassium yourself. To prepare a solution of potassium nitrate, you need to prepare. Ammonium nitrate and potassium chloride are acquired in advance. Reagents can be bought at a gardening shop at affordable prices. To get high-quality nitrate, you need to follow all the steps in order.

Step-by-step preparation of potassium nitrate:

  1. Mix 100 g of potassium chloride and 350 ml of distilled water (hot).
  2. Stir until dissolved and strain.
  3. Pour the mixture into an enamel container and boil.
  4. When boiling is achieved, begin to stir and slowly pour 95 g of ammonium nitrate.
  5. Boil for three minutes, stirring constantly.
  6. Remove the solution from the heat and cool.
  7. Pour the warm solution into a plastic bottle.
  8. After cooling completely, put the bottle in the refrigerator for an hour.
  9. Transfer the bottle to the freezer for 3 hours.
  10. Drain the water, keeping the precipitate of potassium nitrate at the bottom of the bottle.
  11. Dry the crystals on paper (several days in a dry place).

Although many summer residents increasingly refuse mineral supplements, leaning toward organic matter, experienced farmers continue to use saltpeter. Mineral fertilizers are indispensable in those cases when you need to get a good and large crop. Potassium nitrate strengthens the immunity of plants, increases their resistance and improves taste.