What to Put On Bottom of Raised Garden Bed & What Not to Put

Last Updated on June 22, 2022 by Gary Stephen

There is a whole slew of reasons why a raised garden bed is such a good idea, the least of which is the fact that your back will be thanking you in a few years. Apart from that, a raised garden bed can keep out a lot of different critters, like rabbits, for example. It also offers better drainage for your garden, and you don’t need to tilt it every year. There are quite a few perks! With all of these benefits, it’s no wonder so many gardeners are doing just that, especially when they are aiming to make a vegetable or herb garden. But what exactly to put on bottom of raised garden bed? What are the best materials to raise your garden bed with, and, really, should you even be putting anything under there?

In this article, we’ll be taking a look at what to put under your raised garden bed, as well as common mistakes first-time gardeners make when filling it up.

Why should I put anything on the bottom of raised garden bed?

A lot of gardeners might believe there is no reason to put anything under the soil. Soil is soil, so why not just leave it as is? Because a bit of protection between your plants and the earth can save you a lot of work. Like keeping weeds out of your garden, or a pesky burrowing mole.

By putting at least some barrier at the bottom you ensure your garden bed is safe and secure, at least from some of the hazards they are often exposed to. Furthermore, mulch is greatly beneficial to your garden and will help keep your plants happy and healthy in those long dry seasons.

So adding a barrier and some good mulch is the best for your raised garden bed.

1. Cardboard

Cardboard might sound like a strange choice, after all, your garden needs good drainage or else you might end up with root rot or other problems. But cardboard is open enough to let the water soak through, yet strong enough to still keep some of the weeds out of your hair. The only problem with cardboard is it does break down eventually, although it won’t happen every week, you will have to replace it at least yearly.

But don’t just plop the cardboard just down. Rather first spread some mulch at the bottom.

This can be made up of wood chips, straw, grass clippings, and other organic materials. Make this layer about three to four inches thick. Place the cardboard on top of that layer, and you can start adding the soil. This mulch will actually break down and create a sort of compost, which will greatly help to keep moisture in the box.

put cardboard on raised garden bed

2. Newspaper

Much like cardboard, the newspaper will work just as well. Just drop a secure barrier with a bunch of folded newspapers. They are quite easy to come by. Head on over to the local newspaper and ask for a bundle of a previous week or month. They should still have some and they sell them for a song.

put newspaper on the bottom of raised garden bed

Newspapers break down about the same as cardboard, so remember to clean out the bed once in a while.

3. Wire mesh hardware cloth

This mesh is wide enough to allow excellent drainage, while at the same time tight enough to keep out most trouble makers, but it will still let those friendly earthworms through. The mesh is also extremely endurable, and you won’t have any problems with it for a while.

Wire mesh hardware cloth

You simply staple it to the bottom of your box and you’re good to go.

A good idea is to perhaps first put some mulch down, and then staple the mesh on, still giving you that awesome moisture-inducing quality of the compost.

4. Burlap sack

Organic, cheap, with good drainage and it stops weeds, what’s not to love? Much like the wire mesh, all you have to do is stable the burlap sack to the bottom of the box. Once again, remember to still add that mulch at the bottom.

A thing to take note of is both the cardboard box and the burlap sack, unfortunately, prevent earthworms from naturally coming into your garden. So just remember to add them once you’ve started planting.

What You Should Not Put at The Bottom of My Raised Garden Bed

  • Carpet

Although many gardeners will claim carpet is an excellent material to use, in reality, carpet hinders your bed’s ability to function properly. It won’t drain well, it will retain extensive heat, and will even stop some of your plant’s root growth. Steer clear of carpet.

  • Plastic

Although it might look neat, plastic is a terrible material to use in your garden. It will be effective in keeping out pests and weeds, but like the carpet, it won’t drain at all and will stop root growth.

But if you’re having some serious problems with weeds and pests, try combining some of the materials into something that will work for you. Like the mesh and cardboard to make an extra layer of protection against those hazards.

Common Mistakes When Using a Raised Garden Bed

Although a raised garden bed is an excellent idea to get started in your garden, you have to be aware of some of the pitfalls lots of gardeners fall into. So before starting up your garden bed, here are a few things to keep in mind.

  • Don’t make the raised garden bed too wide

raised garden bed too wide
Don’t make the raised garden bed too wide

One of the first rules for making a garden bed is; don’t step on the soil! The best part of having a raised garden bed is the loose soil which gives a lot of extra oxygen to your plants. This helps them grow exponentially. If your garden bed is too wide, you’ll soon be stomping around and flattening the soil, thus preventing the plants from breathing and so hurting you’re their growth.

So, be sure to make your bed wider than 4 feet, that should be a perfect width to reach all of your plants without having the need to step on any of it.

  • No nutrients in the soil

When adding those bags of soil, be extra sure it offers the correct nutrients in both amounts and type. Not any old soil will do, and you have to be sure it will work with your vegetables. Also, make sure that the soil is able to drainage effectively, but at the same time doesn’t drain too quickly. Potting soil, for example, will often drain too quickly. The soil needs to still retain some water to ensure your plants can soak up enough of it.

Lack of nutrient in the soil
Lack of nutrient in the soil
  • Wrong materials

Pressure-treated wood has spurred on many a debate on whether it is safe to use for a raised garden bed. Although there is no general consensus, everyone can agree that anything made before 2003 should not be used.

Wood treated before 2003 will have chromated copper arsenate, which is quite deadly for any garden. So before picking up those old plants, make double sure it wasn’t painted before 2003, but also do a bit of research and figure out which wood will be the best to use for your garden.

Some wood breaks down far too quickly, and the more endurable wood will most likely be too expensive to buy. If you’re specifically looking for untreated wood, try some of these:

  1. Cypress
  2. Oaks
  3. Black locust
  4. Redwood
  5. Black walnut

These woods are very rot-resistant but are also extremely expensive. A good idea is to find some planks a neighbour, farmer or friend is throwing out.

  • No mulch

Mulch is an extremely important part of making a garden bed – as we have been telling for most of this article. It regulates heat and helps retain moisture in your bed. If you don’t add some mulch to the bottom of the bed, your garden simply will not be as effective as it would if it had been added.

Always add mulch to the bottom of those beds, and watch your garden thrive as a result.

So, What You Need to Know about A Raised Garden Bed

Adding a garden bed is an excellent way to save your back and a lot of problems like pests and weeds. Most gardeners use it for an herb or vegetable garden and have seen some excellent results. But you’ll have to be sure that before you get to planting that your bed is well made, and it has been planned out to be effective.

Use the correct materials at the bottom, make sure you add enough mulch, and be sure that your little is not a big bed.

Otherwise, you’ll just end up with a big old disappointment. 

Gary Stephen
Gary Stephen

Hi, I am Gary Stephen. I have been gardening for a long time. Gardening gives us much benefits and pleasure. Many of us desire to have a garden, but it cannot fulfill the desire for the proper guide or instruction of gardening. So, I am eager to help them. For this purpose, I have developed the MyGardenPlant.com website to make a garden with the proper guide. So, you will get me beside you if you want to know anything about gardening.