Compost Tea

What is it and how is it made?

Compost tea is made from high-grade tested compost (about 2 buckets for 1000L of rainwater). This provides the source of the correct bacteria and fungi. It also contains higher-level microbiology such as protozoa.

Rainwater is pumped into a tank called a brewer and heated to 22°C. The high-grade compost is put into a porous bag which is immersed in the brewer (hence the name compost tea). The brew is maintained at 22°C and mechanically aerated. Food for the bacteria and fungi are added including Fulvic Acid, Liquid Kelp, Fish Hydrolysate, Humic Acid, Liquid Aloe-Vera and Oatmeal, (approximately 6 litres of a mix of foods to make 1000L of tea).

The bacteria and fungi begin to multiply to very high numbers. Temperature, oxygen and qualitative monitoring of the organisms with the microscope are critical to ensure that populations do not increase too quickly and that an aerobic environment is maintained. Anaerobic conditions are highly undesirable and can provide conditions for the propagation of disease pathogens that are detrimental to other living organisms such as plants, insects and animals.
After about 24 hours the good microbiology has consumed all the food and nutrient and the compost tea is ready for use.

Soils have three components, physical (sand, silt and clay particles), chemical (Carbon, nitrogen, phosphorous etc.) and biological (bacteria, fungi, protozoa, nematodes and worms). When soil microbiology is in abundance, it improves structure allowing for better water and air movement into the soil as well as water holding capacity. Healthy soil biology also develops a relationship with the plant, trading nutrients such as nitrogen and phosphorous for carbohydrates.

We apply compost tea at 20L/Ha with some additional food to the soil to improve the number and diversity of the soil biology every 6 months.

Compost Tea for disease suppression

Spraying foliage and fruit with biological preparations covers the plant  with fungi and bacteria that out-compete disease causing fungic and bacteria for space and food on the plant.

The application of biological preparations is particularly difficult so throughout the process we test that there is adequate cover on the plant to protect it. Vines need 70% of the plant surface to be covered by good biology for disease suppression.

From trial work we have done over the past 3 years with organically grown Pinot Noir, we believe that soil and vine health will be improved dramatically with this farming system and that the resultant wines are superior to their  conventionally farmed counterparts.

Application rates used are generally at 70 L/Ha in 500 L per water with some additional food to keep them alive on the leaves in mid season. Rates of compost tea and water per hectare vary through out the growing season depending on the canopy size, density and leaf analysis results.