Biochar: What It Is and How to Use It in the Garden

Biochar is a type of charcoal made from plant material that’s been heated in a low-oxygen environment. Unlike regular charcoal, biochar is specifically created for soil application. When added to garden soil, it can improve fertility, retain water and nutrients, and support microbial life—making it a powerful tool for regenerative gardening.

Table of Contents

Why Use Biochar

Enhances Soil Structure: Improves aeration and prevents compaction.
Retains Nutrients and Water: Its porous structure holds nutrients and moisture for plant roots.
Supports Microbes: Provides habitat for beneficial soil organisms, boosting soil life.
Reduces Greenhouse Gases: Stabilizes carbon in soil, helping combat climate change.
Increases Crop Yields: Healthier soil leads to stronger, more productive plants.

How to Apply Biochar

Charge It First: Mix biochar with compost, manure, or soil slurry before application to avoid nutrient drawdown.
Incorporate Into Beds: Blend into raised beds, vegetable rows, or garden soil before planting.
Use as Topdress: Lightly sprinkle and water in around established plants for long-term benefits.
Combine with Organic Matter: Mix with mulch, compost, or cover crops to maximize microbial activity.
Apply Gradually: Start with small amounts (5–10% of soil volume) and increase as soil adapts.

Tips from My Garden

I charge biochar in compost for a few weeks before adding it to raised beds. Over time, soil becomes darker, retains moisture better, and my vegetables look healthier and more resilient. Even a small amount applied consistently each season has noticeable benefits for soil life and structure.

Quick Biochar Cheat Sheet

Step	Action	Tip
Charge	Mix with compost or manure	Avoid nutrient drawdown in soil
Incorporate	Blend into soil before planting	Use 5–10% of soil volume initially
Topdress	Sprinkle around established plants	Water in to activate benefits
Combine	Mix with mulch or cover crops	Boosts microbial activity and carbon storage
Monitor	Observe soil structure, moisture, and plant growth	Adjust application rate over time

How to Make Biochar at Home

You can absolutely make biochar at home—it’s not too hard once you understand the basics, though it does take care and patience. Biochar is simply charcoal made from plant material (like small branches, twigs, or crop residues) that’s burned in a low-oxygen environment so it turns into stable carbon instead of ash.

Here’s a simple overview of how to do it safely at home:

Choose your material: Dry, untreated wood chips, pruned branches, or crop stalks work best.
Use a contained burn: A metal barrel or pit with limited airflow helps control oxygen.
Burn slowly: The goal is a smoldering burn, not open flames—this converts the material into char instead of fully burning it.
Quench the char: Once the material has turned black and brittle, extinguish it with water or cover it to cool.
Charge the biochar: Before adding to your soil, mix it with compost, worm castings, or manure tea to “charge” it with nutrients and microbes.

Once prepared, biochar improves soil structure, moisture retention, and microbial activity, and locks carbon in the ground for decades.

Conclusion

Biochar is a simple yet powerful addition to regenerative gardening. By improving soil structure, retaining water and nutrients, and supporting soil life, it helps create resilient, productive gardens while sequestering carbon. With thoughtful application, biochar becomes a long-term investment in both soil health and climate-friendly gardening.