Advantages of hydroponic vegetable production

  • Hydroponically produced vegetables can be of high quality and need little washing.
  • Soil preparation and weeding is reduced or eliminated.
  • It is possible to produce very high yields of vegetables on a small area because an environment optimal for plant growth is created. All the nutrients and water that the plants need, are available at all times.
  • One does not need good soil to grow vegetables.
  • Water is used efficiently.
  • Pollution of soil with unused nutrients is greatly reduced

Disadvantages of hydroponics

  • Hydroponic production is management, capital and labour intensive.
  • A high level of expertise is required.
  • Daily attention is necessary.
  • Specially formulated, soluble nutrients must always be used.
  • Pests and diseases remain a big risk.
  • Finding a market can be a problem.


The difference between hydroponic vegetable production and production in soil


No soil is required.

Plants are irrigated automatically.

No water stress.

Nutrients are available at all times

Only soluble fertilizers are used.

Hydroponic fertilizer formulations contain a balanced nutrient content

Soil borne diseases can be eliminated

Hydroponic production is not organic because artificial nutrients are always used and plants are usually not grown in soil.

Field production

Good topsoil is required.

Good soil = good drainage, compost, disease-free.

Plants need to be irrigated to minimise water stress

Nutrients must be added to soil.

Unless a laboratory analysis is done, too much or too little nutrients can be added.

Soil borne diseases can build up in the soil.

It is possible to produce organic vegetables in soil because one can use organic fertilizers such as compost and manure.


The difference between hydroponic vegetable production and production in soil

Garden units

  • Source of clean water
  • The right location
  • Specially formulated fertilizer
  • Time to attend to the system daily
  • A little knowledge of plants or gardening
  • A commercial or home made unit


  • Water is the most important consideration. Quality, quantity and reliablity
  • A market. Know what, where and when to market your crop
  • Hydroponics is labour intensive. During peak season, labour must be available for 7 days a week
  • Management skills: Production, labour, marketing, infra-structure
  • Expertise in crop production, fertilization & irrigation, pests and disease management
  • Location: Infra-structure, labour, market, etc
  • Financing: The amount needed depends on the size, type of greenhouse, labour cost and your market
  • Dedication

Know the basics

To be able to produce vegetables successfully year after year, one needs to be familiar with the basics of hydroponics viz: the plant, growth medium, water & nutrients. By relying on recipes only, one will not be able to identify the cause of a problem and you may not be able to correct them.


How do plants function?

Plants have only three types of organs: Leaves, roots and stems. Know what the organs look like and how they function so that you can deal with their needs.


Growth medium

Growth medium is the substitute for soil in hydroponic systems.

The functions of growth medium are:

  • To provide the roots with O2
  • Bring the water and dissolved nutrients in contact with roots
  • Anchor the plants so that they do not fall over

Many different materials can be used as long as they provide the roots with O2, water and nutrients.

In South Africa, gravel is popular in re-circulating systems, sawdust is the most popular for the open bag system / drain to waste system.


Water and nutrients

All the nutrients plants need are dissolved in water and they are supplied to plants every day.

Macro elements (N; P; K; S; Ca) are needed in substantial amounts, whereas plants need very small amounts of micro elements (Fe; Zn; Mn; Mg; Cu; Co, Mg).

It is necessary to use was specially formulated fertilizers. Fertilizers used for hydroponics are more pure (and expensive) than other fertilizers to prevent precipitation and blockages of the system.


Which crops can be grown in a hydroponic system?

Basically all high value crops. Popular in South Africa are tomatoes, cucumbers and peppers in drain to waste systems and lettuce and herbs in gravel flow systems.


Which crop should I grow?

Garden units:

Depends on the choice of the family and the type of unit.

Commercial units:

The most important consideration is the market and the climate. Nobody can make this decision for you. Every situation, every crop and every market has it’s own advantages, disadvantages and requirements.


Which variety do I choose?

There are many vegetable varieties available.

Some were developed specifically for commercial hydroponic production in greenhouses. Local seed companies are able to recommend varieties that are widely adapted and easy to grow.

For house hold units common garden varieties are recommended.



  • Seedlings can be purchased at nurseries, or you can produce them yourself
  • When buying seedlings, look for young plants, the roots must not be stuck to the walls of the seedling tray and must be white, not brown
  • Soil- and water-borne diseases can be transmitted through seedlings
  • Transplant only the strongest seedlings
  • Do not use seedlings that are too old and ‘pot bound’

To produce seedlings, follow instructions on seed packages.


Taking care of plants

Different crops are planted at different spacing. Small plants can be planted close to each other.

Large plants need more space to grow and must be spaced further apart.

Water flow must be checked every day and adjusted when necessary.

If plants turn yellow, it is normally a symptom of nutrient deficiency, too little light or a disease.

Inspect the leaves every day for disease symptoms and insects. Act immediately if a problem occurs.

Tall plants need to be trained and pruned to make optimal use of the expensive greenhouse space



Vegetables are perishable. The shelf life and quality depend on a chain of actions:

  • Pick at the right stage without damage to the plant.
  • Pick early in the morning or when it is cool.
  • Keep picked vegetables out of the sun.
  • Handle carefully.
  • Store them at the right temperature (depends on crop).
  • Use the right packaging (depends on crop and market).
  • Transport with care.