Hydroponics - introduction

In simple words, hydroponics is plant growth without soil. The soil plays an important role in facilitating plant growth but its functionality can be replaced using other sources. Essentially, soil provides support and nutrients. The support in a hydroponic system can be provided by a variety of structures. As for the nutrients, there are a number of organic and conventional nutrient sources that can be used in a hydroponic garden. Even the microbial populations that in soil can associate with plant roots can live and thrive in a hydroponic system.

Hydroponic gardening has many advantages and some of them are key factors for sustainable urban development. Such as the fact that it does not require soil. Making a hydroponic garden suitable for all sorts of environments, including small residences with no garden. It has a potential for faster crop growth and with the right techniques, ie. a precise combination of nutrients and light, it is possible to grow crops faster than in soil. Hydroponic systems require less space as plants in soil grow big roots to search for nutrients. In hydroponics the nutrients are constantly available so the space can be limited by the area needed for the plant canopy.

Soilless growing is less constrained by the growing season and harsh environments. As previously mentioned a hydroponic garden has potential for faster growing when the environment and nutrients are controlled. However, this is possible even in outdoor gardening. The temperature of the roots is often more critical to the plant’s health than the temperature of the leaves, so by controlling the temperature of the nutrient solution in case of outdoor gardens, it is possible to increase plant growth and even grow crops that wouldn’t naturally adapt to the location climate. Additionally, because it doesn’t require soil, hydroponics is a good solution for geographical areas where the soil is poor, like deserts, arid and semi-arid climates.

All in all, hydroponic systems use less water. When plants grow in soil, much of the irrigation water is lost to drainage or evaporation. In hydroponics it is possible to work with covered pipes and recipients and therefore, reduce evaporation. Also, all drainage water is reused by recirculation. Another advantage is the cleaness of the crops. In a traditional garden of lettuce, for instance, more water is spent to wash the crops than the entire water required to grow. Whereas soil gardening can be messy, hydroponics is clean and requires little or no washing of the crops.

There is no need for weeding or herbicides, which may be a small advantage to the small home grower, but for big gardens the time and resources spent on weeding and herbicides is significant. Hydroponics growers have no need to purchase herbicides and do not have to worry about potential damage in their crops caused by them. It can also reduce or eliminate pesticides. Hydroponic gardens are not pest free, especially the outdoor ones. However, the lack of soil provides less hiding space for pests to hide, burrow and reproduce. When the hydroponic garden is indoor, it is possible to apply preventive control techniques to make the environment pest free.

Hydroponics can reduce or eliminate agricultural runoff. In a traditional garden it is difficult to manage agricultural runoff. Rain can wash away nutrients right after the garden has been fertilized. In hydroponics, it is common to dump out the nutrient solution every few weeks to reset the nutrition composition. Plants consume nutrients in different ways and as the time passes the solution may become unbalanced. The water waste however doesn’t need to be discarded, it can be used to fertilize outdoor gardens or potted plants.

It has an ability to manipulate nutrient content and specific characteristics of the crops. In general, studies have shown that hydroponic plants have similar nutrient density compared to the soil grown plants. However, there are specialized methods in hydroponics to modify nutritional content based on the type of nutrients that plants are given in key stages of growth. For instance it is possible to make tomatoes sweeter or control the amount of potassium in vegetables targeted for people with kidney problems. Additionally, indoor gardeners can use various colour lights to induce physical characteristics. For instance blue light can make the plants more compact to reduce vertical space.

Soilless growing is easier and demands less work than growing in soil, and hydroponic gardening can be very simple. It is easy to automate, easy to use fertilizers, require less maintenance, and no weeding. Additionally, once the grower gains experience and master the technique, it is very easy to replicate the results.

Introduction to different systems and equipment

Hydroponic systems are easy to set up and start. The basic components of a system are described below.

The reservoir for the water and nutrient solution can be as simple as a bottle or a plastic container, as long as it is opaque and does not allow light to come in. When the seeds are sprouting the water level should be high enough to reach the net pots and keep the seed humid. After the roots are long enough, the plant itself does not need to be in touch with the water, only the roots, and the level of water in the container can be reduced.

The nutrient solution is stored inside the reservoir, diluted in water. There are many types of nutrient solution for hydroponics systems, and this project focus on the use of bokashi tea.

The growing area is the area that the plants will have to develop and grow. The size of the growing area will generally determine the types crops can be grown in the system. Depending on the location of the system and time of year, there might be a need for artificial light.

The set up of a hydroponic system can use different methods. Some are simpler and require less pieces of equipment than others. In this project we used the deep water culture, as explained here.