Organic matter is essential for a healthy edible kitchen gardens. I am always looking out for ways to get more organic matter into my soil.
feeds soil life
supports an increase in soil life diversity
improves soil structure
helps to retain moisture in the soil.
Regular composting and mulching does builds organic matter in the soil. You don't need to dig it in - the thriving ecological system that exists (or is regenerating) below the surface will draw it down into the soil. Mulch can be expensive to buy, and sourcing reliably seed-free mulch can also be challenging. I use organic sugar cane or local seed-free grass bales in the garden areas where I have salad greens and leafy annuals, but for the rest of it, I often rely on the 'chop and drop' method and living mulch. These help to reduce waste and also simplify work in the garden.
Chop and drop
Chop and drop mulching is a way to harness abundantly growing plants - ones which easily produce a lot of biomass and are happy to be trimmed. A good haircut actually can help the growth and form of many of these plants. Here's a couple of the things I use for this:
legume trees such as acacia and ice-cream bean
The corn has finished so I have knocked it back and left it in situ. When it breaks down some more, I will plant a new crop through it.
I've done similar things with the pumpkin vines when they are finished. You can see here the self-propagating sweet potato coming up through, and the new cutting of Cranberry Hibiscus.
Pigeon Pea is a short lived leguminous shrub (4-5 years) that grows a few metres tall. I regularly chop it back and use it's small soft leaves as mulch around the garden. A good haircut helps the plant keep it's shape and not take too much space. Great edible seeds too - been used in India for thousands of years.
The great big juicy leaves of fast growing QLD Arrowroot (Canna edulis) make great chop and drop mulch in my subtropical garden. The recover quickly too.
Comfrey produces an abundance of leaves that are easily digested by the soil and which add great nutrients. In the middle of the growing season, I regularly take all the leaves off comfrey plants for this purpose and they happily grow back again.
I allow a range of plants to cover the soil and these plants often have many uses (food, fibre, living mulch, habitat ...) which makes them even better than plain mulch in my food forest and polycultural kitchen garden. Some of the plants I use in this way in different parts of my garden are:
Brazilian spinach (clumps)
At the moment, the sweet potato leaves are making a wonderful living mulch as an understory in my food forest. The leaves are edible, and I rarely have weeds growing up through these great mats of plants. This patch of sweet potato in my garden is under turmeric, orange, yakon and cranberry hibiscus and has found a balance with pepino on the ground.
A short film about this topic is on my film list and should be ready soon. I will include more information and details about plants there.
One of my favourites is actually lemongrass because it smells so good. Which plants do you use for chop and drop and living mulch?