Guide to Hydroponic cultivation of vegetables

Bjørn Johansen
8 min read3 days ago

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Guide to Hydroponic cultivation of vegetables

Growing your own food is becoming more and more popular. Hydroponic growing systems use less water than traditional agriculture and are best for crops that you want to harvest quickly.

For example, many people grow lettuce hydroponically because it only takes a few weeks.

However, if you want to try hydroponics, there are a few things you should know.

Table of Contents

It is a method of growing plants without soil. Instead of soil, water and a nutrient solution are used.

You can grow plants with hydroponics all year round — which means you can get fresh produce even in winter!

Hydroponic cultivation also uses less water than traditional soil-based systems. This is because the soil does not absorb much of the water before it reaches the roots. In addition, there is less evaporation because the water does not have to go through the soil.

Startup decisions

Choice of plants you and we grow
Selection of the cultivation system you wish to use.
Choice of growing plug material
Choice of fertilizer
Choice of light

Selection of plants you can grow in hydroponic

Lettuce

Since lettuce is relatively easy to grow, this is a good plant to start with. Salad is also easy to use for most dishes.

Lettuce usually requires cool temperatures and the pH level should be between 6 and 7. In most cases, they will grow in 30 days or less.

Cucumbers

Since cucumber is known to be a hot plant, make sure you provide it with plenty of light and high temperatures. These plants thrive best at a pH level of 5.5 to 6.0.

Cucumbers grow quickly and can produce good yields.

Spinach

In most cases, spinach grows within approx. 40 days. Likes best pH is between 6.0 and 7.5 and warm temperature.

Beans

To grow beans you need a trellis. This will ensure that the plants get proper support when they need it most. Germination will take anywhere from three to eight days, and harvesting can begin around six to eight weeks after that.

Beans thrive best in warm temperatures and the ideal pH level will range from 6.0 to 6.3.

Chives

These herbs are not only easy to grow, but they are also just as easy to maintain. Ideally, chives take around six or eight weeks to fully mature. You can also harvest it roughly daily.

For pH, a level between 6.0 to 6.1 is sufficient.

Tomato

Tomatoes are popular to grow hydroponically, also there are commerical growers that prefer this method.

Tomato needs plenty of light and warm temperatures.

The ideal pH level ranges from 5.5 to 6.5.

Kale
Kale is good for growing in hydroponic systems with moderate temperatures. The pH level should ideally range from 5.5 to 6.5.

Hydroponic growing methods

Kratky method (still water)

The Kratky method was invented by Kratky, at the University of Hawaii. With this method, the plants are allowed to grow in small open pots with the roots hanging partially below the water. The water in the tank is stagnant.

There are a number of challenges that must be taken care of if you want to cultivate without oxygen supply in the water.

The stagnant water attracts bacterial growth and small flies.

Since the supply is constant, the larger the plants, the faster the nutrients are absorbed.

Oxidized water (Aeroponic)

hydroponic system with oxidized water
Plants are placed above the nutrient solution reservoir, so that the roots are directly above the water. In this system, an air pump is used to provide air and oxygen to the roots. This is considered to be the most efficient and stable system. You can use an aquarium pump with a so-called aerator connected to give as many air bubbles as possible.

Drip system

Ebb and flow hydroponic setup
A timer controls a pump that delivers the nutrient solution at a constant rate, from the reservoir to the top of the growing medium where it is absorbed by both the roots and the medium. The excess solution then percolates back into the reservoir for reuse. A variant of this system is what is called Ebb and flow.

Automatic watering with cotton thread

This is the simplest system, because there are no moving parts. Instead, wicks are run from the nutrient solution reservoir to the bottom of the growing container/pot. A system with cotton thread often requires the roots to be placed in a growing medium that retains water, such as coconut fibre.

Growth medium

Clay pellets/leca
Gravel/sand
Hemp fiber
Perlite
Stone wool
Sandy
Sawdust
coconut fiber
hydroponic growth media
Photo by Pragyan Bezbaruah on Pexels.com
Fertilizer alternatives
Powder/granulate fertiliser
granulated fertilizer for hydroponic cultivation based on seaweed and kelp
The advantage of granular fertilizers compared to liquid fertilizers is that they weigh less when you transport them. Granules for hydroponic cultivation must be water-soluble to be able to be used.

Fertilizers

Powder

Powdered fertilizers come in different N-P-K ratios, and the one you choose will depend on the types of plants you grow. An example is that the ratio will be very different for lettuce as it is for tomatoes.

One of the best sources of micronutrients is granular fertilizer for hydroponic cultivation based on seaweed and kelp.

Liquid fertilizer

Liquid nutrients are the easiest to use for hydroponic cultivation.

A major advantage of liquid fertilizer is that there is less chance of residue building up in pipes or water tanks in your system.

Many flying foods also come with pH level buffers, so there won’t be as much need to manually adjust the pH levels.

Organic fertilizer

Although nutrients may be organic, it is difficult to obtain a complete range of advanced nutrients from one source alone. It is common to mix two or more fertilizers that are organic to reach the desired levels of macro and micronutrients.

The main disadvantage of using organic nutrients in hydroponics is that it can be difficult to reach high enough levels of nitrogen and calcium, which is especially difficult for beginners to measure. What happens is that the systems rely on microbes found in the root zone to convert organic compounds into nitrogen sources that are ideal for plants to use. In many cases, this process does not happen quickly enough for the nutrients to be absorbed by the plants.

Light

Sunlight is free, and provides all the light that plants need. The blue spectrum provides healthy leaf growth, while the red spectrum provides flowering and fruiting. Plants that require a lot of sun should be in a south-facing window without shadows. A north-facing window is best for plants that require little light.

Grow light or sunlight?

You may not have plenty of natural light in every room in your home.

By using grow lights you can place your plants anywhere.

Try leaving the plant under artificial light for a few hours if you think your plan isn’t getting enough sunlight. However, your specific situation will determine what works best.

Hydroponic grow systems

Hydroponic mini herb garden

With the hydroponic herb garden, you can have fresh salads and herbs on the kitchen table. It has 9 rows where you can grow whatever you want. Plant the seeds in the vermiculite, adjust the grow light for optimal lighting and let the built-in timer do the rest. The herb garden notifies you when it needs more water, and shows the temperature in the room on the front display.

  • Power: 8.5W
  • Dimensions: 373 x 118 x 302 mm
  • With integrated light source

Kitchen garden

The kitchen garden has space for 12 plants. The grow light has a mixture of red and blue diodes that can be adjusted as needed. It provides optimal light while the plants grow, thanks to the automatic timer that turns the light on for 16 hours and off for 8 hours. It also has a built-in fan that circulates air around the plants, preventing mold and ensuring the best growing conditions. The 4L water tank with pump system ensures even moisture without constant refilling, so that the roots thrive. A small window shows the water level in the tank, so you can always keep an eye on the level.

  • Hole size: Ø3 cm
  • Power: 24W
  • Dimensions: 350 x 387 x 260 mm
  • Integrated light source

Questions and answers about hydroponics

Here are some common questions and answers about hydroponics

What is hydroponic cultivation?
Hydroponics is a method of growing plants without soil. Instead, nutrient-rich water solution is used to give the plants everything they need to grow, including nutrients and minerals. Hydroponics is an efficient way to grow food without using soil.

What are the benefits of hydroponic growing?
Hydroponic cultivation works well indoors, it also offers a reduced risk of pests and diseases compared to plants that are grown in soil indoors. It can also be a more sustainable way to grow food, especially in urban areas with limited space. If you grow your own food with a hydroponic kit, you will get fresh and nutritious food that is uncooked.

What kind of location and lighting do I need to grow plants hydroponically?
The location and lighting you need depends on which plants you want to grow and how many plants you want to grow. Most plants need at least six hours of direct sunlight or additional lighting from LED plant lights to grow optimally. It is important to place the plants in a well-ventilated area and avoid temperatures that are too high or too low.

How can I prevent my plants from getting pests or diseases in hydroponics?
Although hydroponic cultivation may be less prone to pests and diseases than traditional soil-based cultivation, it is still important to take precautions to avoid problems. You can keep the plants clean and healthy by using filtered water, changing the nutrient solution regularly, avoiding over-fertilizing

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