When To Sow Green Manure

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If you are planning on using green manure to improve your soil then one question you will immediately have is when to sow green manure. In this article, I will dig into that question and help you along in your gardening journey. So let’s find out when you should be sowing your own green manure plants.

The main reason for sowing green manure in Autumn is that your beds would normally be empty at this time. So by growing green manure, you are not missing out on having any other crops or flowers in your beds.

If you are unsure of what exactly green manure is and what it does then check out my article What Is Green Manure?

You also get the added benefit of reducing soil erosion over winter by having something growing in the bed rather than having bare, exposed soil.

Then added onto this is another great benefit in that the green manure adds fertility to your soil over winter ready for your crops next spring. As you can see there are a lot of benefits to sowing your green manure in autumn and growing it over winter. This is what I usually do and I use the green manure mix from Mr Fothergills below as it makes the whole process really simple.

Sowing Green Manure At Other Times Of The Year

As I mentioned, even though green manure is usually sown in autumn it can really be sown any time of the year (excluding the middle of winter).

Anytime you have an empty bed and are expecting it to be bare for a while then you could grow green manure. This is what’s often called a catch crop. These are crops you grow in between your main crops.

They are often quick-growing veggies like salad leaves or reddish. But you can also grow green manure as a way of improving your soil.

When grown and then chopped and dropped or dug into your soil then green manure will add fertility to your soil whereas something like a radish will be taking nutrients out of your soil.

Growing For Specific Soil Problems

Sometimes you grow green manure to address a specific problem rather than to just improve the overall fertility of the soil. When you are doing this you often have to grow a specific crop, and these cant be grown year-round like some green manures.

Let’s take lupins as an example of what I mean. Lupins can be grown as a cover crop, this is because they have a large tap root that helps to break up heavy soils and also works really well at bringing up nitrogen deep in your soil.

There are actually lots of reasons that make lupins great as green manure, but I think that is for another article. When it comes to sowing lupins for use as green manure then you want to be doing it in spring.

That means that if you plan on using something like lupins as green manure then there is only one time of year to sow them, whereas with other more standard green manure crops like clover you can sow them anytime except winter.

Specific Green Manures & When To Sow

Looking for a specific date to sow certain green manures? I have gathered some sowing dates on some of the more popular green manure choices below.

Blue Lupins

Should be sown in spring. March-May.

Buckwheat

Can be sown in spring or summer. March-August.

Crimson Clover

Can be sown in spring or summer. March-August.

Field Beans

Can be sown in autumn and grown over winter. September-November.

Red Clover

Can be sown in spring or summer. March-August

Rye

Can be sown in autumn and grown over winter. September-November.

Mustard

A quick-growing crop that can be sown anytime except winter. March-November.

Phacelia

Can be sown in spring or summer. March-August If you are further south it can overwinter in a mild winter so can be sown later.

Crop Rotation

Many green manures fall into one of the specific families of plants that you may want to rotate. Quite a few of them are legumes and so you don’t want to sow them if you plan on growing peas or beans straight after.

So this is another factor you need to think about when deciding on when to sow your green manure. Lupins are legumes so many people will not grow them and then plant peas in the same bed. But brassicas are a great family of plants to grow after lupins.

This is because they love plenty of nitrogen and the lupins will bring up a lot of the nitrogen buried deep in your soil and make it accessible for the brassicas that follow them.

So you could grow lupins in the spring as a green manure and then follow them with some autumn brassicas.

So, When Should You Sow Green Manure?

You should sow green manure whenever it suits and fits into your garden plan. there are green manures that can be grown at pretty much any time of year.

The traditional season for sowing green manure is autumn after your crops are finished for the year. They are grown over winter as a way of protecting your soil and also adding nutrition back into it ready for the following growing season.

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