Growing green manure is easy and a great way of replenishing the soil in your garden! Late summer is a great time to sow some green manure seeds after clearing your summer planting. Of course, you can grow lots of greens during winter as I have described in my previous post. However, if you do have areas where the soil is going to be left bare then it’s a good idea to sow some green manure. Green manures are plants that you can grow in bare patches or beds in your garden or plot, which benefit the soil. They do this is a number of ways.
Benefits of Growing Green Manure
There are several advantages of growing green manures in your garden. I am always reluctant to leave bare patches in my garden, as I find that the next time I turn around, weeds will have taken residence! Green manures are much more preferable in my garden beds over winter.
I also have found that after a whole season of heavy cropping in the summer, the soil becomes exhausted. I am definitely not a fan of popping artificial fertilisers to grow more food over winter. Instead, I like to give these beds which have been busy over summer, a break to recover and replenish themselves in nutrients like nitrogen. This can easily be done with green manures.
Improves Soil Structure
These beneficial plants also help to improve your soil structure, and are known to break up heavy clay and hold lighter soil to prevent erosion in the colder months. This all helps to improve the structure of the soil for spring planting.
Benefits Soil Food Web Structure
In addition, growing these green manures over winter supports the soil food web structure in the ground. The soil food web structure is a whole community of microorganisms that live in the soil. They have have an interrelated relationship with the plant roots and other soil elements, which is vital for a healthy ecosystem in our gardens. Growing green manures, chopping and then dropping the plants for the earth worms to incorporate into the soil is a fabulous way to replenish the soil.
It goes without saying then, that this is a great way of giving your garden soil a much needed rejuvenation in preparation for the following spring … in a much more nature friendly and sustainable way!
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How to grow green manure
I have found it easy growing green manure in my garden over winter. These are the steps I like to follow in general:
a. Preparing the ground
Clear the patch where you’ll be growing your green manure. This means lifting or pulling out root vegetables that have been growing. Trim herbs like chives and remove annuals like french marigolds. If there are any weeds, remove them with the whole root. I like to snip my bean plants at the soil surface, leaving the roots in the bed. This is in the hope that any nitrogen on their root nodules will dissipate into the soil.
b. Sowing the seeds for growing green manures
Late August and September is a great time to sprinkle green manure seeds. Last year I grew Field beans and Phacelia. It is a good idea to measure the area that you are going to sow your green manure seeds in as this will help you buy the amount of right quantity of seeds.
How to Sow your Seeds
- Lightly rake the soil to even the levels. Sow your seeds. This will depend on what you’re growing. If they are field beans, then pop them in according to the directions. However, green manures like Phacelia need to be sprinkled and then raked in. I also measure my beds in order to calculate how much seed to sow in that particular area. It is best to follow the instructions that are supplied with individual varieties of seeds.
- Water your seeds in and watch them grow over winter. No effort required after this stage!
c. Cutting the plants
- I like to cut my green manure while they are young as they have softer stems that can be incorporated easily. The timing will depend on individual green manure varieties. It is also good to catch them before they start flowering, otherwise they will start to produce seeds and then self seed! You can leave a few plants to keep flowering as the bees and butterflies will love them in your garden.
- Cut them down at the base of the plants and leave them on the soil surface. They will wilt and become great mulch.
d. Incorporating the green manure
After a couple of weeks, you can incorporate the green manure mulch into the soil with a garden fork and then leave it alone for a few weeks before planting in early spring. You can also keep the mulch on the surface for the worms to incorporate it for you which makes it even easier!
I have also grown rye and vetch one winter and then snipped them down the following February. You can read more about it in my winter post.
Growing Green Manure – Which one?
There are several different types of green manures. Some help to fix nitrogen into the soil, while others generally enrich the soil with their mulch, help to break up heavy soil or hold the soils structure. Which green manure you choose to grow also depends on what you are planning to grow in spring.
One year, I grew a mix of rye and vetch in two of my beds and this was brilliant for growing my onions, beetroot and radishes. Last year, I grew Phacelia, which was great at enriching the soil in two of my beds. In the other beds, I grew Field Beans which are super nitrogen fixers and perfect growing my leafy greens in spring!
Sow Seeds have a very comprehensive table of information on all types of green manures which I would definitely recommend for you to read.
Hope you will find it as useful as I do in picking your varieties of green manures to sow this season!