How to plant a green manure crop

Estimated reading time: 4 minutes

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Soil preparation can different things to different people. Sometimes people ask how big the hole should be. Or they want to know if they should dig the hole now or wait until they’re planting the tree later in winter.

People also often want to know what else should be added to the hole. Should they put manure, or fertiliser, or something else) in with the tree?

All great questions, but not the topic of today’s blog.

When we talk about soil preparation, we’re talking about a technique you can use to improve the health of the soil before you plant the tree.

The technique is to plant an autumn green manure crop. It’s particularly a good idea if:

you have poor soil
you don’t have enough topsoil
you’re planting a tree into an area where a tree has died or you’re aware there has been disease, or
you’re keen to give your new trees the best possible start in life.

A green manure crop — *It’s good to include as many different types of plants as possible in your green manure*

First, the seed mix for your green manure crop

You can either buy a green manure mix, or make your own. You can find both autumn and spring plant lists in our short course Build Soil Fertility with Green Manures.

We usually buy the seeds separately and mix them together in a bucket before sowing.

It’s a really good idea to add some fine sand (or similar) into the mix to help spread it evenly.

Spreading the seed

Before you broadcast the seed, lightly work up the soil if possible.

If you’re doing a large patch to plant a whole orchard it’s much easier to dothis mechanically with something like a rotary hoe, disc, or plough if you have access to one.

If you’re just doing individual tree sites, or don’t have access to a machine, you can just dig the patch with a shovel.

Select your tree sites first, and then work the soil and plant the green manure crop in an area of at least 1 square metre at each tree site.

Then broadcast the seed, trying to get it evenly spread over the whole area. We usually just do this by hand, but there are lots of different types of seed spreaders available. This is one of the most affordable ones we’ve seen, but we haven’t used it ourselves.

Once you’ve spread the seed, then rake lightly to cover the seed with a fine layer of soil.

When should you plant the green manure crop?

The idea is that you wait until the ‘autumn break’ before you plant. This means after the first decent rainfall event that signals the end of the summer dry period. Depending on your area and climate, hopefully this has already happened and you’ll get enough natural rainfall for the crop to grow.

If you live in a particularly dry area or are currently experiencing drought, it’s still worth trying to get a green manure crop started. However, it’s only really practical to do this on a small area, because you’ll have to water the crop to get any benefit.

Once the crop has grown (ideally to at least a few inches tall), turn it back into the soil. It’s good to do this a few weeks before you plant your fruit trees, to give the green matter a chance to break down in the soil.

That’s it!

It’s a pretty straighforward practice, but the benefits to the soil are enormous.

If you use the right mix of seed you should be adding a wonderful nutritional boost, as well as some bulk material to increase the organic content of your soil and provide lots of lovely food for the soil microbes.