How to Fill Your New Raised Garden Beds Without Going Broke

If you have decided that this is the year you will actually build those raised garden beds, and now you have found yourself wondering how on earth to fill them without spending a fortune, this post is for you.

Depending on the depth of your beds, you could be looking at a lot of soil. But the good news is, you don’t need to fill them with perfect topsoil from top to bottom, in fact, doing so would be a huge waste of money. Instead, get resourceful and use some clever layering, starting from the bottom up.

1. Create a drainage base

If your beds are sitting directly on compacted ground or clay, it’s helpful to add a drainage layer in the bottom. This isn’t essential for everyone, but can be useful if your site tends to hold water.

Use:

• Rocks, stones, or coarse river sand, then

• Small branches or prunings - nothing too chunky - criss crossed over the stony layer. Corn stalks work well here, however you may not have them on hand depending on the time of year it is

Avoid: Big logs or stumps (like in hugelkultur beds) as big logs can tie up nitrogen as they rot and pull it from the soil, which means your veggies might go a bit hungry in the meantime.

2. Add organic bulk

Next you want to start building bulk by adding lasagne type layers that will eventually break down and feed the soil.

Use:

• Old leaves or straw – make sure to wet and compact each layer thoroughly as you go

• Garden waste or pulled-out weeds

• Spent plants - chop these up if they are large, or run them over with the lawn mower!

• Grass clumps or sod from where you have scraped paths around your new gardens. Put them in upside down if they’re in big pieces, with the roots facing up

• Soil scraped from paths or other areas you have landscaped

  
  

Remember to water all these layers as you go, and stamp them down well. They’ll settle eventually, but compacting them a little bit now helps reduce sinkage later.

3. Add whatever soil you can get your hands on

The next layer is your soil - it is good to remember that most vegetables don’t need a metre of perfect soil - they’ll happily grow in the top 15–30 cm if the conditions are right.

So, layer with:

• Any sub-par soil (weed free) you’ve got lying around - this can go lower down

• Better soil or topsoil (store-bought or otherwise) in the upper layers

• Well-rotted manure, farm muck, sheep pellets or worm castings - these are excellent for boosting fertility

• Compost on top - even a thin layer will help kickstart microbial life, but if you can be generous here then all the better!

4. Top it all off

Once you’ve got your bed filled, mulch the top with a generous layer of straw. This will help retain moisture, reduce weeds, and feed your soil while it waits for planting time.

What I wouldn't recommend using to fill your raised bed

• Large logs or pieces of wood - as explained above, these are good fillers for the bottom, but they will pull nitrogen from the soil and steal nutrients from your plants as they break down.

• Glass or sharp items - sometimes it can seem like a good idea to fill the bottom with broken crockery/glass etc, but this will never break down, and could be dangerous with future digging (speaking from experience here!)

• Plastic of any sort - we have enough plastic particles invading our soil - we don't need more

• Soil or organic matter that has noxious weed seeds in it - most weeds are fine to compost but there are a few that should never be welcomed into your garden so make sure you know where any brought in soil actually comes from, and what weed seeds it may hold

Final thoughts:

It's important not to overthink too much when filling new raised gardens - you’re not building a perfect growing medium from the get-go, you’re simply filling your beds with suitable materials in a smart, layered way so that they settle well and are ready to support healthy plant growth. You can always amend the soil later, top up with compost each season, and tweak things as you go.

Remember that even a roughly filled bed is already on its way to feeding your family - much more than an empty one waiting on the “perfect” soil.

If you have any questions at all about this - send me a message - I love to hear from you.