Unit earth

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A cultivation substrate for horticulture developed by Anton Fruhstorfer around 1950 is referred to as standard soil, which consists of around 60 to 70% white peat or raised bog peat and 30 to 40% clay or subsoil loam .

Composition and manufacture

So unit soil is a mixture of peat and lime-free clay. It is produced industrially from peat or earthworks and has the advantage over the practice soils used in horticulture (mixtures of organic residues and mineral substances produced in the horticultural business) that it has a constant composition. It is also free of pollutants, pathogens and pests (because it is dampened). They therefore offer the gardener greater security in cultivating than when using natural substrates. Standard soil, with a volume weight of 300 to 400 g / l, is also significantly lighter than a grown soil, which has a volume weight of approx. 1.5 kg / l.

The added clay mostly comes from the subsoil and is therefore practically inanimate. The clay used should form stable crumbs when chopped up and not become muddy when watered. Since lime-free clays are preferred and peat is usually strongly acidic, the pH value of the substrate is adjusted to a weakly acidic value of 5.6 to 6.5 by adding lime , which only has an unfavorable effect on cultivation in a few cases. Because of the ability to store nutrients and water, watering and fertilizing dates can be varied to a limited extent. The favorable pore volume of the peat ensures the air balance of the unit earth (the air capacity is between 10 and 45% vol), so that it is largely spill-proof. Depending on the intended use, nutrients are also added to the standard soil .

Types of unit earth

Various mixtures are produced. A distinction is made in retail:

  • Main earths:
    • Type 0 ( zero earth ): unfertilized, can be used for sensitive seeds and cuttings as well as a base substrate for special crops , which is fertilized as required.
    • Type VM ( propagation soil): addition of Styromull, looser than type 0, low nutrient content from a mixture of fast and slow-acting fertilizers, 1 to 1.5 g compound fertilizer (MND) per liter of substrate, for sowing and cuttings, for pricking and for Cultivation of poorly growing and salt-sensitive crops (e.g. ferns).
    • Type ED 73 or 76 ED 73 : fertilized with 2 to 2.5 g MND / l substrate, divided into fast-acting fertilizers and slow-acting depot fertilizers (e.g. Plantosan 4D), with an effect of 2 to 3 months. For potting salt-sensitive and nutrient-needy plants.
    • Type T ( potting soil ): heavily fertilized, up to 3 g MND / l substrate, to be used for heavily consuming and mature plants, for potting from spring to autumn.
    • Type P ( pricking soil ): slightly fertilized, approx. 1.5 g to 2 g MND / l substrate, suitable for most horticultural crops and for potting in winter.

literature

  • R. Rober, K. Schaller: Plant nutrition in horticulture, manual of the commercial gardener . Publisher Eugen Ulmer, Stuttgart 1985
  • H. Seipel: Expertise for gardeners . Verlag Handwerk und Technik GmbH, Hamburg 2004
  • Ulrich Sachweh (editor): Basics of horticulture . Verlag Eugen Ulmer, Stuttgart 1984, 2001, ISBN 3-8001-1184-5 , p. 327

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