Hydroponics: basic methods and techniques for growing garden crops at home

Recommendation points

• A bit of history
• Basic hydroponic techniques
• Aquatic culture
• Substrate culture
• Aerial culture (aeroponics)
• Composition of nutrient solutions
• Hydroponic growing substrates
• The main types of hydroponic systems

Hydroponics is considered by many scientists to be the technology of the future, which will help humanity solve the problem of lack of food and drinking water. In the article, we will consider hydroponic methods, study nutrient solutions, and answer which modern materials are suitable as substrates for growing.

Hydroponics is a method of growing plants without soil using artificial substrates and nutrient solutions. This progressive method is based on modern technology, but it is based on simple natural principles. In fact, hydroponics is the oldest form of plant life. After all, as you know, life originated in water, and hydroponic photosynthetic algae existed long before the appearance of various plants on land.

A bit of history

Already in the 18th century, scientists discovered that plants are able to absorb nutrients from water. Under natural conditions, the soil acts as a so-called reservoir with the necessary minerals, but its presence is not an absolute condition for the life of various cultures. It should be noted that plants begin to absorb mineral substances from the soil only when they dissolve in water..

Hydroponics as we know it today emerged in the early twentieth century (1920s – 1930s). It was during this time that the English scientist William F. Guerick was able to remove aquatic culture from laboratory conditions and put hydroponics on an industrial basis. He owns the very term “hydroponics”, and most experts consider him the founder of this science.

William F. Guerick

The use of hydroponics on a large scale first occurred during World War II, when the US Army faced food shortages in the Pacific Islands. This method took root there so that growing plants using hydroponics continued after the war, until the 50s..

Hydroponics got a new life in the 60s and 70s of the twentieth century, when the industrial production of various synthetic materials began. So, mineral wool was used as a substrate, and lightweight plastic structures replaced hydroponic concrete baths. At the same time, artificial chelates began to be produced, which made it possible to retain minerals in nutrient solutions much more efficiently..

In 1978, General Hydroponics was founded. Its founder, Lawrence Brooks, set about improving large-scale hydroponic structures down to the size of an urban greenhouse. Since that time, hydroponics has become very popular among vegetable and fruit growers..

In 1986, at the All-Russian Industrial Exhibition, the method of growing crops on artificial substrates, the author of which was Timiryazev, was first demonstrated. In the same year, Israeli agronomist Hillel Soffer invented the whirlpool, which is still considered the most efficient hydroponic system..

Since the mid-80s, two opposite directions have appeared in hydroponics – industrial and home. This division has survived to this day. There are many options for hydroponic systems on the agricultural market today, ranging from industrial scale installations to home structures that can be placed in almost any apartment. Let’s take a closer look at what hydroponic methods are now, and what is the peculiarity of each of them..

Basic hydroponic techniques

The main feature of this method of cultivation is that the plants are cultivated without soil, and all the necessary nutrients are obtained from a humid-air, aqueous or solid porous medium. This method of cultivation requires frequent or constant drip irrigation with a special solution, which contains all the necessary elements required for each individual crop. Today, experts distinguish between three main methods of hydroponics:

1. Aquatic culture.
2. Substrate culture.
3. Aerial culture (aeroponics).

Aquatic culture

Aquatic culture is considered the foundational method of hydroponics. In this growing method, the plant is rooted in a thin layer of some organic substrate (moss, peat, etc.), which is laid on a net. The mesh is lowered into a tray filled with nutrient solution. The roots of plants through the substrate and holes in the pan enter the solution, from where the plant receives all the nutrients necessary for development and growth. We will talk more about the composition of the nutrient solution a little later..

Aquatic culture is considered to be the oldest hydroponic method, but by no means the best. The main problem with this method of growing is aeration of the roots, because the amount of oxygen contained in the solution is not enough for the plant, therefore it is impossible to completely lower the root system into the nutrient medium. To ensure normal respiration, an air space of 3 cm for young plants and 6 cm for adult crops is left between the base and the nutrient solution. At the same time, in such an air cushion, it is necessary to maintain high air humidity, otherwise the root system can quickly dry out. When growing by water culture, the nutrient solution must be changed every month.

Substrate culture

With this method of cultivation, the root system is placed in a thick layer of substrate, which can be expanded clay, gravel, vermiculite and others. We will talk in more detail about the qualities of materials used for substrates in the next chapter. Plant nutrition using this hydroponic method can be carried out according to three different principles: the principle of backwater, the principle of periodic moistening, watering from above.

Backwater principlelies in the fact that the nutrient solution is constantly located only in the lower layer of the substrate. Nutrition is provided thanks to long roots that can penetrate to the very bottom – the necessary substances rise to the plant, passing through the capillaries of the root system and stem tissues.

The container with the plant and the substrate is completely placed in the nutrient solution for a while, the substrate is saturated with nutrients, after which the solution is drained – this is work the principle of periodic humidification.

Most easy to use watering principle from above.In this case, several times a week the plants are watered with a nutrient solution, once with plain water..

Unlike water, the substrate culture allows you to provide the root system with oxygen to the maximum and maintain the necessary moisture in the root area without problems. That is why it is the most popular among hydroponic growers..

Aerial culture (aeroponics)

Aeroponics is a method of growing plants without any substrate at all. In this case, two methods are used:

1. The plants are attached with special clips to the lid of the container with the nutrient solution so that the lower part of the root system is 1/3 in it. The rest of the roots are located in an air cushion between the container lid and the nutrient solution, they must be periodically moistened. In order to avoid damage and thickening of the stem in the area of ​​attachment, use foam rubber spacers between the clamp and the stem.
2. The root system of the plant is placed in a vessel with a fogging spray, which sprays the nutrient solution in the form of very small drops 2 times a day for 3-4 minutes.

When using aeroponics, there are no problems with oxygen supply, however, it is necessary to constantly maintain high air humidity in order to avoid drying out of the roots..

Composition of nutrient solutions

Nutrient solutions play a huge role in growing plants using hydroponics. It is from them that crops receive all the mineral substances necessary for normal development and growth. When preparing nutrient solutions, it is very important to adhere to the following guidelines:

• pay attention to water quality;
• the nutrient solution must contain all the macro- and microelements necessary for the life of a particular culture;
• at different periods of life, the plant requires a different ratio of nutrients, therefore, the solution must be prepared, taking into account the growth phases of the culture;
• it is very important to observe not only the correct ratio, but also the total concentration, which should be high enough, but, at the same time, not toxic to plants.

As you can see, the preparation of a nutrient solution is a rather complicated matter, therefore, for those who wish to organize hydroponic beds on the windowsill, it is best to use ready-made solutions that can be purchased in specialized stores or via the Internet. We will talk in more detail about growing plants in a city apartment using hydroponics in the next article..

Hydroponic growing substrates

As already noted, due to the optimal saturation of the root system with oxygen and the ability to maintain the necessary air humidity, the substrate culture is considered the best method of hydroponics. Today, various materials are used as a substrate, the most common of which are:

• hydrogel
• gravel
• sawdust
• mineral wool
• expanded clay
• coconut fiber
• peat and moss

Hydrogelis made on the basis of pollyacrylamide and is used for the main cultivation of crops, as well as for rooting cuttings and germinating seeds. Initially, a hydrogel is a powder or granules, which, when water is added, turn into a gel-like mass. The hydrogel perfectly absorbs and retains water and nutrient solutions, the air between its granules circulates very well. This material is sterile, completely non-toxic to plants and does not pollute the environment (after 5 years it decomposes into water, carbon dioxide and nitrogen).

Gravelhas been used for hydroponic cultivation for many years, during which it has proven itself to be an excellent substrate. A distinctive feature of this material is its ability to remarkably pass air, but at the same time it does not retain water well, therefore it is most advisable to use it when applying the principle of periodic flooding. Another disadvantage of gravel is its weight, but its low cost and availability make this material quite popular for hydroponic cultivation. In addition, gravel can be reused, and more than once, the main thing is to sterilize it well between harvests..

Sawdustrarely used as a substrate. When using them, the type of wood from which these sawdust was obtained plays an important role, since some species (pine, oak, walnut) can emit substances that are unsafe for many plants. Another problem when using sawdust as a substrate is that after a certain time they begin to rot, which negatively affects the health of crops. The main advantage of sawdust can be considered their “freeiness”, because, in most cases, they can be collected in unlimited quantities at sawmills absolutely free.

Mineral woolrarely used as a substrate. The main advantage of this material is the ability to very quickly accept the acidity of the nutrient solution. However, mineral wool retains too much water without leaving room for oxygen around the roots..

Expanded claymost experienced professionals consider the best material to use as a substrate. Expanded clay is made by baking clay in ovens at very high temperatures. This method of production determines the specific characteristics of the material – expanded clay balls are filled with tiny air bubbles, which makes this substrate extremely light. The use of expanded clay ensures optimal oxygen supply to the roots and the maintenance of the necessary moisture. These properties make it possible to use it as a substrate for periodic flooding, for irrigation from above, and for the application of the backwater principle. Along with the above-described positive qualities, expanded clay is also distinguished by its low cost..

Coconut fiberis an ideal material for use as a substrate for growing plants without soil. It has only one drawback – a relatively high price. When it comes to providing the root system with oxygen and maintaining the necessary moisture, coconut fiber is second to none. In addition, this material remarkably protects the roots from fungal diseases and has a number of undeniable advantages:

• ecological cleanliness, absence of any chemical additives;
• the acidity of coconut fiber is close to optimal, suitable for most crops;
• the substrate can be used for a long time (about 6–8 years);
• with a constant supply of nutrient solution ensures the perfect balance of all nutrients.

Peat and mossused as a substrate mainly in aquatic culture for rooting seedlings on a mesh tray. Sphagnum peat and moss from raised bogs are most suitable for growing plants. This material is highly oxygen permeable and retains a sufficient amount of moisture. The main disadvantage of this substrate is that over time it can decompose into small particles that clog the elements of the hydroponic system..

The main types of hydroponic systems

Today, the agricultural market offers a wide range of structures for growing plants using hydroponics. All these systems are divided into two main groups: active and passive..

Active hydroponic plants are equipped with mechanical devices (pumps) that ensure the constant necessary circulation of the nutrient solution. A forced aeration system is also provided here, that is, saturation of the root system with oxygen. Aeroponics are a good example of an active hydroponic plant..

In passive hydroponic installations, the nutrient solution is supplied to the roots and the surface of the plant only due to the capillary forces of the culture itself, in this case it is not subjected to any mechanical stress. A good example of passive hydroponic installations is systems that operate on the principle of periodic flooding of substrate crops.

Today, growing plants without soil is used more and more often, especially in small farms, where in small areas, thanks to hydroponics, it is possible to grow decent yields of greens, vegetables, berries and flowers..

Hydroponics has a number of undeniable advantages over traditional soil cultivation:

• economical use of water and land resources;
• the plant does not waste energy on the search for nutrients, they are fed directly to the roots, and all the energy saved goes to growth and additional fruiting.

Many scientists consider hydroponics to be the solution to humanity’s problems of overpopulation, lack of fresh water and food. This plant growing system is especially relevant in countries with an arid climate and lack of fertile land. With the help of hydroponics, it is possible to get several harvests per year, using this method, tomatoes, cucumbers and other vegetables can be grown even in regions with low year-round temperatures..