How to use biochar

Biochar needs to be ‘charged’ with nutrients, water and micro-organisms before use. We recommend using one of the following methods for charging biochar (please see the website for more information):

  1. Add biochar to your compost bin/heap. Biochar will add structure to the final compost. It acts as a repository for organic nutrients, water and provides a home for beneficial microbes and fungi. Aim for 10-20% biochar in the final compost. The biochar/compost mix will be ready for use once the composting process is complete.
  2. Fill a large bucket or other vessel with biochar and mix-in compost, well-rotted animal manure and other organic nutrients. Add water until completely immersed. Then leave for two weeks (stirring every few days). 80:20 ratio of compost to biochar is recommended.

Once the biochar is ‘charged’, there are several methods for applying to your soil.

  1. It is best dug-in to the soil for immediate benefits to the soil characteristics.
  2. Alternatively, you can use as a mulch for top-dressing. This is best for trees and shrubs.

Charged biochar is best incorporated with soils from late autumn through to spring and left to settle for a couple of weeks before planting.

We recommend adding 0.6kg of biochar (~30 handfuls) per metre squared per year. If using a charged biochar/compost mix you will need to adjust your calculation based on the ratio between biochar and compost. You are aiming to build-up the amount of biochar in the soil slowly over time, with the long-term aim of getting to ~5% of biochar in the soil rootzone. The rootzone is generally considered to be the top 20 cm of soil. Target 5% built-up over a number of years.

Biochar can be used all year round and with any soil type. It is suitable for trees, flowers, fruit and vegetables.

Instructions for container use

Biochar needs to be ‘charged’ with nutrients, water and micro-organisms before use with pots and containers. See above for more information.

The table below sets out application rate based on an 80:20 compost biochar mix:

Container Size Charged Biochar Compost Application Rate Effective biochar Amount
1 L 25g ~ 1 handfuls 5% 1%
5 L 125g ~ 5 handfuls 5% 1%
10 L 250g ~ 10 handfuls 5% 1%
15 L 375g ~ 15 handfuls 5% 1%
20 L 500g ~ 20 handfuls 5% 1%
25 L 625g ~ 25 handfuls 5% 1%
30 L 750g ~ 30 handfuls 5% 1%

Leave a Reply

Your email address will not be published. Required fields are marked *