Published in The Green Issue 202
When speaking of the types of plants we have here on The Ridge and the functions they perform, we often speak of chopping and dropping. To “chop and drop” is a foundational principle in permaculture and the concept couldn’t be more self-explanatory. You simply chop the plant and drop it on the ground. As simple as it sounds (and is) there is a little more science behind why we do it and the types of plants we do it with.
So first, the why; why cut plants off and leave them on the ground? This is a highly efficient way of creating mulch in our gardens and is quite a lot less labour intensive than buying in and spreading commercial mulches. To begin with, it’s already exactly where you need it, it’s free and because you know exactly where it has come from you know that it doesn’t contain any weed species or external pesticides. All of these factors are a bonus if you are trying to live an organic lifestyle.
The types of plants to use for chopping and dropping are often referred to as support species, as they provide the medium for optimum soil health and plant productivity for our edible staples. They do this through their mulch, by providing a physical barrier against things such as sun, wind or heavy rain and also by providing nutrients to the other plants.
Atmospheric nitrogen is captured by growing plants and stored (usually in nodules on the roots). When the plant dies or is pruned (chopped) it releases its store of nitrogen into the soil in a form that is directly accessible by other plants. Nitrogen is one of the primary elements required for plant growth, so it follows that if all your other needs (water, sun etc.) are met, then extra nitrogen in the soil will result in a greater amount of growth (great news for your kitchen garden and food forest). Therefore, if you have a fast-growing support species that you can chop and drop often, you will make more essential nutrients available to your food plants more regularly.
The larger support species that fulfil this role in our garden are pigeon peas, arrowroot, lemon grass and comfrey. Plants such as Crotalaria, Leucaena and tagasaste (tree lucerne) can also be used. On the smaller scale are the green manure crops we use intensively on individual garden beds of which cow peas, lab lab, oats, wheat and lucerne can be used.