Struggling to figure out what is the best soil for raised beds?
There’s a fair bit of conflicting advice out there, but this article will help you work out how to create the best mix for the plants you’re wanting to grow this season.
You may well be wondering:
How Do You Fill A Raised Bed Cheaply?
Um….well, you’re not going to like the answer to this, because the fact is that filling raised beds is a bit of a stinger in the wallet at the outset.
The main message here is: don’t try to skimp on it.
I’ve cited some articles written by a variety of gardening experts and they all give the same advice:
“ Don’t try to save money by buying cheap soil for your raised beds.”
Cheap soil is likely to be lacking in nutrients and full of stones and other ingredients that won’t benefit your plants.
That will affect the yield you get from your garden, and therefore cost you more in the long run.
Ready for Some Good News?
However, there is some good news: you only have to fill your raised beds once, and then simply top-up in subsequent seasons, so the main financial outlay is just at the beginning.
There, did that help a bit?
Top Tip!
Yes, the best soil for raised beds is expensive, but you’re not going to need to fill the whole depth of your beds with it: only the depth of the roots of the veggies or plants you’re going to be growing.
However, You Can Save Yourself Some Money
Save money by filling only the top section where your plants are going to be growing with the best quality soil mixture you can afford-( more about that to come.)
Meanwhile, in the bottom of your beds, where your plants are not going to reach, you can fill up with cheaper materials:
- Stones
- Wood
- Straw bales
- Gravel
- sand
Stones, sand and gravel will improve the drainage of your beds and the organic materials- straw and wood- will rot down and gradually create a lovely organic environment down there to feed our friends: worms and microbes.
Is There A Difference Between Garden Soil and Raised Bed Soil?
Yes. Garden soil tends to become oversaturated with water and lacking nutrients such as perlite and peat.
Because of its high moisture content, garden soil can be very corrosive to your plants as it contains a higher volume of salts than is desirable.
So, What is the Best Soil Mixture for Raised Beds?
The best soil for raised beds contains a mixture of ingredients:
- Compost
- Peat moss
- Vermiculture
- Topsoil
You’ll need to get yourself a tarpaulin and create the winning mixture of these components before you start shoveling it into your raised beds.
Let’s look at what these different components bring to the table:
Compost
Well-rotted compost should be the largest component of your mixture, as it contains all the nutrients your plants are going to need to flourish.
Not only that, if you’ve been nourishing a compost heap all year, it’s FREE!!
If you haven’t got your own compost heap, then you can buy some by clicking the link in my shopping list below.
Peat Moss
The great thing about peat moss is its ability to help the soil retain water and nutrients long enough for your plants to absorb all the water they need.
It’s also helpful in breaking up the compost and topsoil that would otherwise be too dense.
The ideal texture of your soil should be light, crumbly and soft, and adding peat moss helps to achieve this.
Vermiculite
This is an important component of the best soil for raised beds as it helps with both drainage and aeration.
If you’re not sure what vermiculture is, it’s the process of using worms to convert organic waste into nutrient-rich compost.
Don’t worry, you don’t have to buy and cultivate a load of worms yourself, you can just buy the great compost they produce. (Thankfully!)
Topsoil
This is the top layer of soil which contains organic matter and will form an important ingredient for your mixture- about 50%, as a rough guide.
You’ll be able to purchase this from your main local garden and building supplies centre.
Look at the labels and choose the organic options designed for growing vegetables and flowers rather than more general gardening and lawns.
This is where it pays to choose the more expensive options if you can.
This will save a lot of grief in the future, trying to rebalance poor quality soil which isn’t going to adequately nourish your plants.
What is the Recipe for the Best Soil for Raised Beds?
This depends on the plants you’re intending to grow, but a general rule of thumb is:
- 50% topsoil
- 30% compost
- 20% organic matter which can include manure, mulch and vermiculture
Growing Berries?
If you intend to grow strawberries or blueberries, choose the more acidic topsoil that has been designed especially for these kinds of plants.
Growing Tomatoes?
Tomatoes benefit from a slightly acidic soil, so you may wish to add more peat moss to the mixture.
Growing Cactii or Succulents?
Add sand to improve drainage.
What Is the Best Fertiliser For Raised Beds?
There is a wide variety of options for you here. The best fertiliser is well-rotted compost from your compost heap; that should add most or all of the nutrients your plants are going to need.
If you need to purchase compost, then be sure to choose organic options. There are plenty of choices- click here to learn more
Once Your Raised Beds are Established
Once your raised beds are established, you don’t have to go to the expense of replacing the soil each growing season.
When spring comes around you’ll find that the levels of soil in your beds will have sank somewhat.
This is due to heavy rains and snow over winter washing it away.
Top up your beds with a thick layer of mulch and compost and cover your beds with black plastic until the ground is warm enough for planting.
Many gardeners seed their beds with green manure at the end of the growing season in the autumn.
This cover crop feeds the soil with nitrogen and nutrients ready for spring planting.
If you want to learn more about growing green manure, then click here to read my article.
Ready to go shopping?
Find my Amazon shopping list below:
Further Reading for you:
How To Prepare Your Raised Beds for Spring
Top 8 Materials To Create Attractive and Productive Raised Beds
Use Raised Beds To Easily Grow More In Your Garden
Raised Beds: Soil Depth Requirements
Affiliate Disclosure: This article may contains affiliate links. Should you click on them and make a purchase then I will make a small commission at no extra cost to you. However, it will go some way towards funding my expensive coffee habit, for which I will be forever grateful.