On Sunday 22 October we welcomed Charles Otway from TerraPerma to our garden to talk about weeds. He covered many interesting topics including what weeds can tell us about our soil and how we can use them to our advantage.
The first point Charles made was that the weeds growing in your garden can tell you a-lot about the properties of your soil. Weeds invariably grow better than anything you might be trying to cultivate so rather than fight them, learn to appreciate them! Charles is a big fan of eating weeds as they often have a superior nutritional profile compared to cultivated crops. Weed eating may be an acquired taste as the higher nutritional profile can mean that flavours are more bitter than we are used to.
Looking at which weeds are flourishing is an indicator of soil health. If you have a lot of:
- Grasses, chances are your soil structure needs stabilizing and more carbon.
- Legumes indicate poor soil nitrogen levels and leaving them to grow can help boost your soil fertility due to their ability to fix atmospheric nitrogen in the root zone.
- Weeds with deep tap roots serve to break up compacted soil. They also indicate that your topsoil may need minerals, which they are able to bring up from lower down in the soil profile.
If you want to remove weeds but not lose the nutrients that they are bringing up, the best thing to do is to use a knife to cut just under the soil surface leaving the roots in place, and then leave the weed so that it can wilt on the surface.
What do you do if your weeds have flowered and set seed? Charles made the point that unless your compost reaches 65°C for ten days weed seeds will likely survive and spreading your compost will simply spread them. Most home compost heaps can’t achieve this temperature so an alternative is to steep weeds in water for several months, then strain and use as a liquid fertilizer.
Charles then took us on a ramble around our garden and pointed out all the great weeds that we can eat. Do make sure you know what you’re eating isn’t poisonous and if you’re foraging in public places that you are sure the weeds haven’t been sprayed with herbicide.
If you’re interested in finding out more, Charles has an excellent array of resources on his Terra Perma Design website:
- Free workshop notes
- Edible Weeds and Foraging guide for Perth – Full Booklet
- Edible Weeds book – just words for printing in black and white
- Edible Weeds colour slides – for the above book