I reckon that it is a good gardening practice to grow as many green crops as you possibly can. I use it as part of my overall strategy to keep my soil as healthy to make sure that I get the best crops possible. The aim is to increase the organic matter in the soil to improve the soil structure.
As the organic matter decomposes, it slowly releases nutrients into the soil for your veggies to take up. It’s a natural slow release fertiliser that does not get washed away like chemical fertilizers do. The decomposing organic matter also provides a habitat for beneficial microorganisms and worms to thrive, which in turn improves soil quality. It also improves your soil structure by allowing water and air to penetrate deep down to the roots of the plants. Your soil will become more porous and easier to cultivate. It’s the perfect cure to bent and forked carrots!
The time of year will determine which crop I grow. In the summer months I have used Mung Beans, Soy Beans, French Marigolds and Mustard. In autumn it’s Barley or Oats and in Winter I like to use Fava Beans (broad beans). This list is by no means complete, there are many more plants that can be used. The general rule of thumb is that the green crop plant is fast growing and leafy.
Some other benefits of selecting the right green crop is that they can help to break the life cycle of pests in your soil. French Marigolds will help break the life cycle of the pesky mongrel Nematodes that can inhabit you soil and Mustard can be used as a natural soil fumigant. Another benefit can be gained if you use legumes. Beans are legumes and they able to lock nitrogen onto their roots as they grow. It then becomes available for the next crop you grow in the same location.
The best time to dig them into the soil is when the crop starts to flower. A couple of reasons why – it is when the crop is at its maximum foliage stage of development and also, you want to knock it down before seeds set and you inherit a weed problem for future crops. I usually pull out the hedge trimmer and chop it down by decreasing the height by 10cm each pass until the crop is about 5cm tall. This makes the green foliage easier to dig into the soil. It will take a couple of goes of digging to eventually get it all underground. You will need to repeat it every 2 weeks or so and it will be ready to plant into in around 4 weeks after you start digging. Don’t be shy to plant if the green crop has not completely rotted away.
So, as you plan your veggie garden schedule this spring, plan to add a green manure crop to improve the quality of your soil. I do and I reckon it is a great way to improve your harvests for many seasons ahead.