Worm soil

Worm Soil (also known as vermicast or worm casts) is the natural product of the decomposition of organic matter by earthworms. Vermicast contains a high concentration of water-soluble nutrients and micro-organisms and is an excellent fertiliser. It enhances the water retention of soils helping to prevent topsoil erosion and increasing drought resistance in plants.

In essence worms are fed with organic waste material (in this case horse manure) which they then consume and decompose to produce the nutrient rich soil conditioner – Worm Soil.

Worm Soil has many benefits both for the structure of the soil itself and for any plants that are growing within it. This table provides a breakdown of the qualities of Worm Soil and the beneficial effects it has when added to the soil.

Benefits of Worm Soil

Beneficial effects when added to soil:

High organic matter content 

– Organic matter forms soil aggregates which protect against soil erosion 

– Improves soil aeration, porosity and water retention

– High nutrient concentration (including nitrogen, potassium, Phosphorus (NKP), Calcium, Magnesium)

– High cation exchange capacity

– Increases nutrient content of soil 

– Greater cation exchange capacity increases the uptake of nutrients through the roots.

– crops have a higher nutrient content

Humic and fulvic acid

Humic and fulvic acid increase nutrient uptake in plants

Low soluble salt levels

Lower soluble salts within the soil mean it is easier for plant roots to absorb water and soluble nutrients

Low Carbon to Nitrogen ratio

Low C:N means more nutrients are available to plants

High and diverse microbial population

Healthy soil microbiome:

  • Makes nutrients and minerals in the soil more available to plants
  • Increases the availability of plant growth hormones 
  • Is essential in the defence mechanisms of plants’ resistance to stresses (eg. drought/frost), pests, parasites and pathogens

In addition, less nitrogen is released into the air during the decomposition process than during traditional composting.

When added to your soil, Worm Soil improves the soils’ structure and microbiome as well as giving plants the ingredients they need to grow, develop a strong root system and fight off pests and disease. Increased yields with a higher nutrient content are also a significant benefit of Worm Soil.


turnips with vermicast

Worm Soil acts as a fertiliser, soil conditioner and increases the resistance to droughts and frosts as well as acting as a natural pest and disease control.


Worm Soil can be used to restore poor quality soils as well as on an established plot.


Kinder to the environment than the use and production of synthetic fertilisers and pesticides, it is a natural, chemical free product which is safe to use around humans and pets. 

Worm Soil uses a mixture of locally sourced horse manure and shredded cardboard to produce a stable soil enhancer with the best carbon to nitrogen ratio. It is produced in worm beds using Tiger Worms (Eisenia Fetida) on site at Park Farm, Shropshire. 

Worm diagram

The vermicast is harvested and sieved to remove larger particles which are then added back to the worm beds.

Worm Soil is rich in nutrients, fulvic and humic acid and essential micro-organisms. It is to be used as an additive, rather than for direct planting like traditional compost. In this way, Worm Soil is an economic option for soil and plant improvement.


Mix approximately 1 part Worm Soil with 4 parts traditional compost or soil to realise the full benefits for your plants and soil. 

Using 100% of Worm Soil will not result in incremental benefits for your crops, making Worm Soil a cost effective option.

Vegetables and annuals seeds: Sprinkle roughly ½ inch of Worm Soil in the bottom of a seed drill before placing the seeds. Cover and water as normal. When growth is showing above ground spread 1-2 handfuls per foot along the row.

Potting up – mix 1 part Worm Soil with 4 parts compost or soil. For existing plants, top dress the container with ½ inch of Worm Soil then water.

Planting out – Either mix 1 part Worm Soil with 4 parts compost or soil or sprinkle 1 – 2 handfuls into the bottom of the hole. Top dress with 1-2 handfuls every 2 months during the growing season.

Perennials – 4 times a year, top dress with 2 handfuls per plant, working it gently into the soil above the roots, then water.

Established Shrubs and Trees – Work 3 handfuls into the top 2 inches of soil surrounding the  plants then water. Repeat up to 3 times during the growing season.

Bulbs – Mix 1 part Worm Soil with 4 parts compost/soil before planting. Top dress with 1-2 handfuls when flowering.

Houseplants – Top dress with ½ inch of Worm Soil then water.

New lawns  – Use 2.5 litre for 3 – 4 square meters. Spread over the new lawn turf or mix with grass seed and scatter. Water.

Established lawns – Use 2.5 litres for 3 – 4 square meters. Scatter over the whole area and water (rain can help!). Repeat up to 4 times during the growing season.

Receive exclusive subscriber offers, news and other info!

subscribe to receive a 25% Discount code in honour of our 1st Birthday!