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Raised Beds, Topsoil or Compost?

When it comes to filling your raised beds up should you use topsoil or compost? And if you are using topsoil should you just dig some out of the garden or buy some bags from the shop? Let’s have a look and answer all those nagging questions about filling your new raised beds.

topsoil or compost raised beds
topsoil or compost raised beds

Topsoil or compost?

When filling my raised beds I actually like to use a mixture of both topsoil and compost. Topsoil is cheaper and free if you get it from the garden or allotment but compost provides better nutrition for your plants. When mixed together you get a better balance between value and quality.

I also like to make sure I add topsoil straight from my allotment to my raised beds rather than using stuff from a bag. I do this because you get a few benefits this way, firstly it is free which is always great news. But more importantly, you add really useful creatures like worms and nematodes to your raised beds this way which will improve the soil and help keep on top of slugs!

What should I fill my raised beds with?

If you are filling a large raised bed and are worried that you don’t have enough soil and compost then here are a few money-saving things you can put in.

Grass clippings and weed cuttings can be added to the bottom of a raised bed. These will break down over time and turn into free compost.

You can also add large bits of wood and branches to raised beds along with bark. These will take up a little nitrogen from the soil as they decompose but as long as they are at the bottom and you have plenty of soil and compost above you will be absolutely fine.

Fill the bottom with weeds, soil, sticks
Fill the bottom with weeds, soil, sticks

If you have dug your raised bed out of the ground and removed some turf then you can also add this to the bottom of the raised bed. Just make sure it is upside down so the grass is facing downwards and that you put plenty of material on top of it.

What is the difference between topsoil and compost?

Topsoil is literally what it sounds like, the top layer of soil taken straight from the ground. The stuff you buy in shops is usually sourced from building sites when the soil is being removed.

Because it is the top layer of soil it is usually pretty nutrient-poor and is not an ideal soil to grow straight into.

Compost on the other hand is made up of all kinds of organic matter that has been allowed to rot down or ‘compost’. This stuff is full of nutrients and is just what your plants need to thrive.

Should you mix soil and compost?

Yes, mixing the two is a great way to build up a healthy soil.