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Want to improve your garden soil while helping restore Palouse Prairie? Grab a bag of biochar from The Phoenix Conservancy!


A fancy word for charcoalized organic material, biochar has been used by indigenous people for millenia to improve soil quality. Now, biochar is getting renewed attention as a low-cost, low-tech method for converting plant matter into stable, carbon-rich residues. Not only does it lock carbon underground, biochar can drastically improve acidic, compacted soils for generations of farmers, producers, and gardeners with only a single application.


Our biochar is produced with waste brush and weeds collected around the Palouse Prairie during our restoration activities. This means that every bag of biochar we produce represents land restored for endangered ecosystems.


We offer coarse and fine particle size options. Coarser biochar (particles between 1 and 3 inches in diameter) decompose more slowly, better prevent soil compaction, and increase filtration efficiency. Finer biochar (particles under 1 inch in diameter) is best suited for garden applications in smaller quantities, since it is easier to incorporate into compost and garden soils. 


Simply add 1 cubic foot of biochar for every 5 cubic feet of soil to substantially increase water retention and decrease soil acidity. For example, a 20-inch diameter planter would need about 15 standard cups of biochar (1/8th of a cubic foot).  If you have a bed that is 5ft x 10 ft x 2ft (100 cubic feet of soil), you may want about 20 cubic feet of biochar.


The exact amount of biochar needed varies on the soil type and quality you already, so if you would like exact estimates, you can consult online calculators that are a Google search away. However, a little biochar goes a long way, and you can always add more if you'd like. Plus, once you add biochar, it's there to stay for hundreds of years.


If you would like to purchase biochar in bulk, please reach out to to inquire about rates and availability.

Biochar (1 cubic foot)

Expected shipment in March 2024.
  • The Phoenix Conservancy's biochar is made from a mix of feedstocks (e.g., waste brush, weeds, and varies paper-based products like cardboard). Our biochar starts as a coarse material, with average particle size generally staying between 1 and 3 inches in diameter, which is best used to prevent soil compaction and increase filtration efficiency. Our finer material option generally stays under 1 inch in diameter and is best used in garden applications.

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