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Janurary 2010

Compost Tea - Update and grower comment

Soil-Tech Solutions Compost Tea

Compost Tea has been applied in the UK over a wide range of crops including edible and ornamental subjects.

For a number of years the use of fungi, bacteria, nematodes and protozoa has been an attractive environmental option in promoting plant health.

The stimulation of plant growth as a direct result of a healthy environment is a consequence of the regular applications of Compost Tea.

Soil-Tech Solutions are a Dutch company owned by the Van Iersel family and have been at the forefront of Compost Tea and humic compost technology for many years.

Van Iersel - Soil-Tech Solutions based in Biezenmortel Holland, produce not only Compost Tea from quality raw materials, but also from humic tea composts, which have significance in improving soils by enriching soil profiles with microflora. Mark Van Iersel, who runs Soil-Tech Solutions, is passionate about the development of "Tea" and their approach to improving poor soil structure with their product range.

Regular grower meetings are held at Biezenmortel with the most recent event being a residue free forum on soft fruit.

Martin van der Water, technical advisor to Soil-Tech Solutions recently addressed an IPPS meeting at Wyevale Nurseries and the extract that follows is from that meeting.

Martin presented information on Compost Tea from the Dutch perspective. The Netherlands uses Tea on soft fruit, salads, vegetables as well as nursery stock. Soil-Tech Solutions (STS) produces a range of composts made from green waste as well as Tea products and Martin advises growers who use the Tea system. He described the two types of Tea available; fungal (based on humic acids) and bacterial (based on for example fulvic acids) - application depends on plant species and requirement. A good brew should provide a stable ratio of carbon to nitrogen to help the beneficial microorganisms successfully multiply and compete for food.

Martin raised some important points about the machine and equipment maintenance which would help to produce a good quality brew with minimum contamination.
He advised users to:
  • Check the bubbler inside for contamination.
  • Replace the sock regularly of the bubbler to ensure it is still tight.
  • Clean the air filter on the compressor.
  • Aerate tapwater at least 30 minutes until 1 hour before starting the brew.
  • Make sure the ingredients that need to be dissolved into the water have fully dissolved.
  • Ensure the dissolved oxygen is above 6ppm at all times. Oxygen meters are widely available in the UK.
  • Replace the tap sieve each year, especially if it starts to become difficult to keep clean.
  • The sieve should be cleaned immediatey after use, using a pressure washer, soaked in bleach and then rinsed thoroughly with water.
  • Choose your disinfectant carefully as the strength and any residues can affect the next brew.
  • The bagged humic tea compost used for brewing will last for one year after purchase if stored correctly.
  • Get brews analysed throughout the year to ensure consistent brewing.
Liquid nutrients and silica-based products were also introduced for their compatibility with Compost Tea to improve foliar trace element uptake.

Quality and activity of Compost Tea is influenced by factors such as the compost source, the water source, the ingredients source, cleanliness of the brewer and application method. Other practices such as the addition of nutrients, the aeration time, dilution and application frequency and length of brewing time can also determine the viability of Tea.

Osburton Nurseries Worksop Notts - Grower Comment

Osberton Nursery have just completed their first full year using Compost Tea. The benefits have been a vast improvement in both the propagation and the growing on stages of the nursery.

Although adaptions to the growing techniques have complemented the use of Compost Tea, the effects have been substantial in providing the plants and microbes with nutrients.

Through a combination of good husbandry, fertilisers, growing and watering techniques the Compost Tea has stimulated the organisms both in the soil and on the crops to manage the available nutrients to the crops needs. Disease suppression has been improved as a result of the improved vitality of the crop.

The overall chemical use has decreased by over 50% which is excellent for the environment and staff. The plants have responded with notable developments in all areas of growth, which has improved disease resistance through providing a better eco-climate for the plant growth.

Darek said that: "growers must be prepared to put time into mixing and cleaning before and after application. Evening applications may also need to be actioned to avoid day heat".


Soil tech is a trademark of Van Iersel.