Why Biochar Compost is Essential for Healthier Soil This Autumn

As the growing season draws to a close, soils are often left depleted just as winter approaches. Autumn is the most effective time to rebuild and protect soil health, ensuring strong performance in the seasons ahead. Using the best compost for autumn soil improvement, such as SoilFixer Biochar Composts, allows you to restore nutrients, enhance soil structure, and support long-term biological activity — creating the conditions for a healthier, more resilient garden come spring.

Why Use the Best Compost for Autumn Soil Improvement?

Biochar Compost Ingredients: What’s in SF40 and SF60?

Our SF60 starts life as SF40, before we enrich it with the ideal amount of composted horse manure.

• SF40 contains 20% biochar, 70% locally and sustainably sourced composted brash, and 10% composted horse manure. This is our growing media compost — perfect for pots, beds, and general use.
• SF60 (our soil improver) contains 20% biochar, 20% locally and sustainably sourced composted brash, and 60% composted horse manure.

Why Apply Biochar Compost in Autumn?

Autumn warmth and moisture (with soils above 8°C) make this a prime time to apply the best compost for autumn soil improvement. Biochar compost supports microbial life through the winter and provides an early boost as temperatures rise again in spring.

Over winter, compost and biochar integrate further as microbes enter and colonise the biochar’s pores — ‘inoculating’ it. This enhances its role as the best compost for autumn soil improvement, helping to retain nutrients for spring planting while reducing leaching during heavy autumn rain.

Should I Use SF40 or SF60 Over Winter?

For vegetable and flower growers, we recommend SF60. It delivers a much-needed boost of microbes, providing essential biological benefits to your plants as they move into spring.

Before we make SF60 by adding the horse manure, it all begins as SF40 — and our microbiome readings are exceptional, boasting over 1400 µg/g. In other words, it’s highly active, biologically rich compost!

If you’re looking to boost lawns, trees, or shrubs, our SF40 multi-purpose compost provides a healthy foundation to support growth throughout the winter.

Great Long-Term Effects

Healthy soil doesn’t happen by accident — it’s built through regular care and attention. Autumn is the perfect time to start. By applying biochar compost now, you’re feeding your soil, supporting microbial life, and locking away carbon for the future.