How much good stuff you need

Wonder how much good stuff you need?

This page can help you quantify your needs.



To find how much you need, first calculate the surface area of your project (e.g. basket, bed, garden, lawn). To obtain this, multiply the length by the width. This will often be sufficient, for instance to determine how much amendment you need when top-dressing.

If you are filling a new volume, you will need to multiply your project's surface area by it's depth. Or simply put, multiply the length by the width by the depth.

When amending by volume to incorporate in depth, you will need to multiply your project's volume by the recommended proportion. For instance biochar amendment is typically recommended at 5-10% v/v. In other words, multiply the length by the width by the depth by the proportion.

Remember to keep all measurements in the same unit. For instance if your bed is only 6 inches, use 0.5 feet! Helpful tips: there are 27 cubic feet in a cubic yard, and 1000 litres in a cubic meter. And 1 cubic yard = 0.76 cubic meter.

Click on the links below for tools that can help you to:


Depth, and how to limit required volume

All plants don't have the same depth requirements. For instance, radishes or lettuce can do with 4-6'' inches, but tomatoes would require much more. For new beds, a good practice to limit the volume of good soil you need to purchase can be to provide just enough depth and fill the bottom with rotting/semi-composted wood (small logs, branches, twigs), cheaper topsoil, or even inert material such as rocks or even styrofoam. Click on the link below for a great resource and chart to