Factsheets

on specific topics related to potting soil and growing media

Factsheet Unfertilised growing media
Unfertilised growing media are substrates supplied to the grower without added fertilisers. For substrates based on peat raw materials, however, this is not recommended. During cultivation it can lead to a strong pH drop, an imbalance in the availability of trace elements, and reduced uptake of nutritional elements. 

Factsheet Horsetail
Horsetail (Equisetum arvense), also known as field horsetail, is a perennial plant that establishes itself deep in the soil with an extensive root system. The species is tough and difficult to remove. Due to its strong rhizomes and root tubers, which easily sprout again, horsetail is a persistent weed in public spaces.

Factsheet Heavy metals in growing media
Heavy metals occur naturally and through industrial pollution. Some heavy metals are required as trace elements for plant growth. Excessive levels can be harmful. With consumption crops also to human. For food safety and to prevent soil contamination in the environment, legislation limits the total heavy metal content in consumption crops and in raw materials and growing media for soil-based applications. But what about growing media for cultures in pots or containers?

Factsheet Weeds in the culture on substrate
Weeds in the culture are undesirable. They can enter a crop unnoticed via various infection sources and disrupt the culture. Although it is not impossible for the delivered substrate to be the cause of a weed contamination, in the vast
majority of cases, other sources are to blame. How can problems be prevented?

Factsheet Packaged growing media
Producers package growing media and potting soils into big bales, small bales, and bags. Occasionally, a breakdown process can occur in these packages, particularly in fertilised and limed organic substrates or potting soils. In some cases, this can change the product and occasionally cause growth problems in plants. Read the first insights from ongoing RHP research on this topic.

Factsheet DNA research
Growers increasingly want to know in advance whether there are harmful fungi or bacteria in the substrate supplied. DNA research is therefore regularly carried out on growing media. They hope to determine whether it is free of
harmful organisms. DNA research is also used more often to determine the cause of damage in a culture. But how reliable are the results?

Factsheet Sciara
Fungus Gnat (Sciara) regularly occurs in crops on mainly organic growing media. The larva of this fly can cause culture damage. Was the substrate already infected upon delivery? That remains to be seen, for the fly is indigenous troughout
Western Europe. All about the risks and control.

Factsheet Fungal growth
Growing media often contain fungi and they can also grow visibly in and on them. These are usually saprotrophic fungi, which are completely harmless to plants. Growing media produced with renewable raw materials are more susceptible to fungal growth. What are the risks of fungal growth?

Factsheet Pesticides
Pesticides are risky substances that control pests, usually to protect crops. After the use of pesticides, residues can sometimes remain in the environment for a longer period of time. Can pesticide residues also occur in potting soil or substrates and what are the risks?

Factsheet Human pathogens
Human pathogens are micro organisms (e.g. bacteria) that can cause diseases to humans if they come into direct contact with. Can human pathogens be present in potting soil or growing media and what are the risks?