HYDROPONIC GARDEN: WHAT IT IS FOR AND HOW IT WORKS - ENVIRONMENT - 2025

The hydroponic garden is a growing system based on a series of techniques that make it possible to dispense with the soil as a substrate and supplier of nutrients. The word hydroponics derives from the Greek "hydro" (water) and "ponos" (labor), being literally "work in water".

Hydroponic gardens allow to obtain food, medicinal or ornamental plants where there is no adequate soil for cultivation. At the same time, they guarantee a more efficient use of water and nutrients, generating economic savings.

Hydroponic strawberry cultivation. Source: Efrenquevedo

The operation of the hydroponic garden depends on the specific system that is implemented. In general terms, it consists of an inert support substrate for the plant and a nutrient solution that provides it with water and essential minerals.

The nutrient solution is supplied either in a static or recirculating form and should have a pH tending to neutral. In addition, good oxygenation and maintaining a temperature below 28ºC is required.

There are two basic hydroponic systems that can be implemented in a garden which are: cultivation in water or floating root and cultivation in inert substrate. In the floating root plant, the plant is attached to a platform that floats on the nutrient solution. While in the inert substrate system, various support materials are used (coconut fiber, vermiculite, sand) and the nutrient solution is applied by irrigation.

Following the basic principles of hydroponics, there are many ways that a home hydroponic garden can be made. Here three basic proposals are presented, two of them according to the inert substrate culture system and the third one based on floating roots.

What is a hydroponic garden for?

Lettuce grown by hydroponics. Source: David Arqueas

The hydroponic garden is used to produce food, medicinal or ornamental plants where there is no suitable soil for agriculture. In addition, risks of diseases associated with the soil, which cause serious losses in crops, are avoided.

Similarly, it is a system that allows a more efficient control of the water and nutrients supplied to the crop. Likewise, hydroponics allows you to take advantage of the nutrients since the surplus nutrient solution can be reused.

With hydroponic methods, a garden can be established in almost any rural or urban area. Therefore, it is possible to take advantage of sites that are not suitable for a traditional garden (infertile soils, rough terrain, grow houses or heated greenhouses).

On the other hand, in the hydroponic garden the yields per unit area are high due to higher density, productivity and efficiency in the use of resources. As a general principle, it is about achieving maximum production and quality with minimum space and minimum consumption of resources.

The hydroponic garden is developed in growing houses or in greenhouses, so it is not affected by weather conditions. Likewise, it is more protected against pest attacks and can be grown throughout the year.

How does it work?

The basic principle of the hydroponic garden is to provide the plants with a support substrate and to supply an aqueous nutrient solution prepared for this purpose. Additionally, the other factors required for the development of the crop such as light, temperature and protection against pests must be guaranteed.

- The nutritive solution

A nutrient solution is an aqueous substance that contains dissolved oxygen and all essential mineral nutrients for normal plant growth. The success of the hydroponic garden depends largely on the quality of the nutrient solution, the balance of mineral ions and the pH.

In commercial productions, the nutrient solution is carefully formulated according to the specific needs of each crop.

Physical properties

The nutrient solution must have a pH between 5.3 and 5.5, as well as adequate aeration to guarantee good oxygenation. The temperature of the nutrient solution must be kept below 28ºC to favor dissolved oxygen and avoid an increase in the respiratory rate of the roots.

On the other hand, it must be taken into account that the high content of salts (sodium and chloride ions) negatively influence the absorption of nutrients.

Supply

The nutrient solution is supplied either in static or recirculating form. In the static solution system, the garden plants sink their roots into deep containers that contain the nutrient solution.

This solution is replenished as it is consumed and must be oxygenated by forced aeration (air pumps or compressors). In addition, the nutrient solution circulates permanently or intermittently through the system.

If the culture is in an inert substrate, the solution is added and the excess or percolated is collected. For this, channels with an inclination of 1.5% are used where the solution moves by gravity soaking the roots and is recycled by pumping.

- Types of hydroponic gardens

Hydroponic tomato cultivation. Source:

The hydroponic garden can be designed according to two basic categories of hydroponic techniques:

Culture in water

This group includes techniques such as culture in rafts (floating root) and the nutritive film technique (NFT).

In raft culture, the roots of the plants float in the nutrient solution. Likewise, the plant is supported on a sheet of floating polystyrene material (anime, plumage, aislapol).

In the NFT the plants are fixed to a support (for example a foam cube) and the nutrient solution flows constantly through the roots. These systems require special care with the aeration of the nutrient solution.

Inert substrate culture

In this case, various inert substrates such as peat, coconut fiber, vermiculite, perlite, sand or rock wool are used. This system is less demanding in care than the water culture system.

It consists of having a solid substrate that supports the plants and helps retain the nutrient solution.

How to make a home hydroponic garden?

Hydroponic cultivation. Source: charlie vinz from chicago

To establish a hydroponic garden at home, the first thing to do is define the appropriate space, since the most suitable design will be defined based on it. It is necessary that the selected place allows the garden to receive at least 6 hours of sunlight daily.

Another important factor is having a constant water supply as this is a vital element in the system. In addition, a transparent plastic (polyethylene) cover should be built as a roof to protect the hydroponic garden from rain.

Although in commercial systems the nutrient solution is specifically formulated, at home it is more practical to use commercially available organic liquid fertilizers. For example, biol derived from biodigesters or liquid worm humus.

- Seedling

Regardless of the design of the hydroponic garden based on the selected system, there are crop species that require a seedling-transplant phase.

Such is the case of tomato, lettuce and chives that require the seedling-transplant phase. On the other hand, species such as radish, strawberry or pea can be sown directly.

The seedbed is a space that provides the conditions for germination as a preliminary step before being transplanted to the hydroponic garden. It consists of trays 2 to 3 cm deep in which a very fine and uniform inert substrate is added, for example a mixture of peat and vermiculite.

Small furrows are made in which the seeds are deposited at the corresponding sowing distance (variable depending on the crop). Then the furrows are covered by slightly imprisoning to guarantee the contact of the seed with the substrate and we proceed to water.

Watering should be done twice a day, taking care that the seedling is always wet and from the emergence of the seedlings they will be watered with a nutrient solution.

After 15 or 35 days after germination (depending on the species), the seedlings are “hardened”. This procedure consists of reducing the frequency of irrigation to prepare them for the most difficult conditions after transplanting.

After 20 or 40 days, the seedlings are ready to be transplanted, for which the most robust ones will be selected.

- The hydroponic garden

There are several alternatives to make a hydroponic garden at home, some very simple and others somewhat more elaborate. Below we will present three basic proposals:

Hydroponic garden in tray and table

A rectangular wooden or plastic table should be available, the size of which will depend on the available space. Plastic planters (with perforated base) will be placed on the table with their respective collection tray at the bottom.

Likewise, any other type of container can be used as long as it is between 15 and 20 cm deep.

An inert substrate is added, either washed river sand or coconut fiber, or a mixture of 60% coconut fiber and 40% sand. In this substrate, the species to be cultivated will be sown or transplanted, depending on the case.

In the transplant, a hole is made in the substrate with a depth equal to the length of the root, taking care that the neck of the plant is half a cm below the substrate. In direct sowing, the seed should be placed at a depth equal to approximately twice the length of the seed.

The nutrient solution should be applied daily, moistening the substrate until it drains from the bottom, recovering the excess. As it is a small garden, pest control is carried out manually with periodic reviews.

Hydroponic garden in PVC pipes on vertical support

This variant is ideal for transplant crops. PVC pipes with equidistant flute-like perforations are used and are laid slightly inclined (1.5% slope). The distance of the perforations will vary depending on the crop (planting distance) and the tube must be filled with coconut fiber.

A seedling is transplanted into each hole and nutrient solution is added through the higher end until the surplus comes out of the lower end. On the other side of the tube, an attached container is placed to recover the excess nutrient solution.

Floating root hydroponic garden

This method is applicable for transplant crops and requires a 15 cm deep tray and a 1 inch thick (2.5 cm) polystyrene sheet. The polystyrene sheet must be the same shape as the tray, but 2 cm shorter in length and width.

2.5 cm circular perforations are made in the sheet (a half-inch hot galvanized tube can be used) separated at the planting distance. If the crop used is lettuce, the perforations will be arranged in a triangle 17 cm apart.

The tray is filled with nutrient solution and on top of it is placed the polystyrene sheet with a plant in each hole and the roots floating in the nutrient solution.

The polystyrene sheet acts as a lid, restricting the passage of light into the solution, which restricts the growth of algae in the solution. A pumping system (aquarium pump) must be installed to ensure oxygenation of the solution.

References

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