Biochar Multi-Purpose Compost (SF40)

A ready-to-use multi-purpose compost used as a general plant growing media for containers, potting on and raised beds. It is also the go-to biochar-compost grade for improving topsoil and converting soil into Terra Preta type soil. 

Stock available

 

SF40 Multi-Purpose Compost Features

• Peat free
• Coir free
• Contains 20% biochar and 80% sustainable local great quality compost  
• Ideal for organic growing (our compost has no added chemicals)
• Made in Surrey, UK from 100% clean plant and wood sources, all sustainably sourced

 

What is used for and how?

Incorporating into Soil

• New Beds or Containers: Mix compost thoroughly into the top few inches of soil before planting.
• Established Beds: Loosen the soil gently and work the compost into the top 6–8 inches.
• Recommended Ratios: Aim for a 20–30% compost-to-soil mix by volume.

Top Dressing

• Around Existing Plants: Apply a ½ to 1-inch layer of colloidal compost around the base of plants, extending out to the drip line.
• Lawns: Spread a light, even ½-inch layer of finely sifted compost across the lawn surface to support healthy growth.

Potting Mixes

• Mixing: Combine colloidal compost with standard potting soil to create a nutrient-rich, water-retentive medium.
• Ratios: Start with a 20–50% compost blend, adjusting based on plant needs and soil texture.
• Water Balance: Colloidal compost boosts moisture retention—ideal for sandy soils but be cautious in mixes with high clay content to maintain aeration.

It is ready to use straight away - add to containers and plant your plants

• For soil improvement - dig or rake into your soil

 

Benefits

• Ideal for growing plants and vegetables
• Biochar-humus matrix provides excellent water retention
• Contains slow-release macro-nutrients (NKP) supply
• Contains plant trace micro-nutrients (Ca, Mg, etc)
• Improves nutrient supply to plant roots (increased microbe/fungal roots associations that increase nutrient supply to roots (eg mycorrhizal fungi, AMF)
• Improves soil aggregation leading to improved tilth and aeration (essential oxygen flow to roots and microbes)

Pack sizes

• 10 Kg sack (approx. 20 litres)
• 20 Kg sack (approx. 40 litres)
• 0.5 m3 and 1m3 bulk bags 
• For bulk loose orders please email help@soilfixer.co.uk to discuss

 

Delivery 48 hours (except over weekends)

 

How does the product work?

Our multi-purpose compost acts like a sponge—soaking up water and essential nutrients, then releasing them slowly to nourish your plants over time. Carefully crafted from local and sustainably sourced materials, it's designed to support strong, healthy growth and boost the nutritional value of your plants. 

 

When should I use SF40?

Gardeners using biochar are often aiming to create rich, fertile, loamy soil—something like the legendary Amazonian Dark Earth (ADE or Terra Preta). But this level of fertility isn’t achieved simply by adding biochar alone. True soil health—its fertility, structure (tilth), and aggregation—depends on the presence of humus.

Humus forms through microbial activity and interactions with root hairs. It's the dark, sticky substance that holds nutrients and moisture in the soil, and it plays a vital role in sustaining plant life.

Our SF40 is specially formulated to deliver immediate benefits to plant health, while also supporting the natural processes that build humus over time. The result? A living, thriving soil ecosystem that keeps getting better.