A greenhouse in the garden brings a number of advantages. On the one hand, the harvest can be extended and, on the other hand, the crop yields can be increased. However, this requires a good composition of the greenhouse soil. More on that below.

In a nutshell

  • Composition of the greenhouse soil important for a good harvest
  • Substrate does not necessarily have to be replaced annually
  • regular refreshment of the greenhouse soil is usually sufficient
  • Crop rotation must be observed

Greenhouse Soil - Composition

The composition, structure and nutrient content of the soil in the greenhouse is crucial for the growth and a good harvest of vegetables. The soil used should have the following characteristics:

  • loose and airy
  • crumbly to finely crumbly
  • nutritious
  • must not condense
  • no formation of waterlogging

A good soil for the greenhouse should be mixed as follows:

greenhouse in the garden

garden soil

  • at least a third
  • can be loose or tight

horse and cow manure

  • very good alternative to compost
  • contains many nutrients
  • Note origin
  • only use from organic farms

compost

  • if there is no manure
  • very nutritious
  • use one third

Clay

  • incorporate twelve parts clay
  • don't use too much
  • solidified soil
  • soil that is too dry becomes wetter

sand

  • six parts of sand
  • loosens soils
  • brings moisture to the soil
  • not too much, degrades nutrient content

peat

  • not very environmentally friendly
  • However, it lowers the pH of the soil
  • only used when the soil should become more acidic
  • Be sure to measure the pH beforehand

lime

  • Use when the soil is too acidic
  • use twelve parts lime
  • improves soil structure
  • incorporate before planting time

bark mulch

  • nutritious
  • retains moisture in the soil
  • give over ground all year round

Notice: If sowing takes place, the soil must not be too nutrient-rich. If possible, do not use compost, instead use sand.

Refreshing is usually sufficient

The soil in the greenhouse is used more intensively during a gardening season than outdoors. The plants regularly extract nutrients from the soil and the microorganisms also decompose the individual soil components in a greenhouse faster than in a normal garden soil. Nevertheless, replacing the greenhouse soil is not necessary every year. As a rule, refreshing the soil, i.e. supplying new plant food, is completely sufficient. Refreshing, or better yet regular nutrient intake, can be done in a number of ways:

  • Incorporation of rotted cattle manure
  • undermined before planting the summer crops
  • 6 kg manure per square meter per year
  • Training is also possible in late autumn

use of horse manure

  • prior to incorporation, store well with peat or soil for a year
  • Work in like cattle manure

Notice: Regular use of manure keeps the soil fertile for a long time. It is then not necessary to replace the earth every year.

Calcium cyanamide & compost

  • good alternative to stable manure
  • Compost must be well matured and screened
  • Apply and work in a regular 5 to 10 cm layer
  • to do this, remove old soil at the same height
  • however, wild herbs can emerge
  • therefore mix 150 g of special calcium cyanamide per square meter of surface

manure peat

  • suitable for heavy and light soils
  • nevertheless use of stable manure necessary
  • one-sided, prolonged use of peat mulches soil
  • making it difficult to absorb water

use of liquid manure

nettle manure
  • well suited nettle or comfrey manure
  • nutritious
  • protect against salinization of the soil

irrigation water with compost

  • Add compost to the irrigation water
  • stir frequently and thoroughly
  • must dissolve well
  • strain and pour

Observe crop rotation

It is also very important to observe crop rotation so that you do not have to constantly change the soil in the greenhouse. The most diverse plants also have different demands on the soil nutrients, so the correct order in cultivation is necessary so that they can be used optimally. Normally, the soil is able to regenerate itself, but this takes time. In other words, the same plants should not always be planted in the same location every year. A break of at least three years is always recommended.

Notice: In addition, careful and deep tillage is always necessary to prevent the subsoil from drying out or becoming waterlogged.

Experts advise…

changing the soil in the greenhouse every three to four years. If the soil is not completely drained, it is usually sufficient to remove the top layer of 20 to 30 cm and apply fresh soil. However, if the soil no longer has any nutrient content, a complete replacement is required. For this purpose, a layer of soil of 40 to 50 cm is exchanged. The best time to do this is late March to mid-April. However, a soil analysis should be carried out before a complete replacement. This should contain information on the pH value and humus and nutrient content.

reasons for exchange

When using inorganic fertilisers, the growth of soil organisms is inhibited and associated with this is a constant leaching of the soil, with the result that the soil has to be replaced at regular intervals.
The plants themselves indicate when the soil no longer has the appropriate nutrient content. The following features then appear:

  • Soil fungi such as Fusarium or nematodes contained in the soil
  • Plant vitality is lacking
  • Use of larger amounts of fertilizers necessary
  • bad drainage
  • Increased occurrence of pests such as aphids, fungus gnats
  • lightened leaves, small fruits (magnesium deficiency)
  • stunted growth (potassium deficiency)
  • leaf fall, short stature (phosphorus deficiency)
  • white leaves (iron deficiency)

frequently asked Questions

Why does the substrate in the greenhouse begin to mold?

As a rule, the plants are then too dense, which means that mold has an easy time of it. In addition, the humidity and temperature should also be checked regularly. At temperatures between 15 and 25 °C, humidity between 60 and 83 percent is usually sufficient.

Why is the greenhouse soil suddenly turning green?

The reason for the discoloration can be algae. In other words, incorrect watering behavior and insufficient ventilation of the greenhouse are responsible. The soil should then be kept a little drier, but must never dry out. Furthermore, it should then be aired several times, i.e. opening the skylights, windows and doors.

How deep should the soil be in a greenhouse?

It depends on what is to be grown, the decisive factor here is the root depth of the respective plants. For example, if only shallow roots such as herbs or leafy vegetables are to be grown, 10 to 20 cm is sufficient. The situation is different with legumes, stalks, fruit and root vegetables; here the depth should be at least 50 cm.

Category:

Garden maintenance