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What Do I Put on the Bottom of a Raised Garden Bed? 4 Things

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Weeds are one of the challenges of gardening. They take up too much space and remove sunlight, water, and nutrients from your plants. They also invite insects that can do more damage to your crop.

Gardening in a raised garden bed is a great option to prevent weeds. It also allows easier control in improving the soil, better drainage, and lesser work for your back.

Now, you might ask, “what do I put on the bottom of a raised garden bed”?

The most used materials for a raised garden bed liner are cardboard, mulch, concrete, fabric, and plastic. They serve as a barrier between your garden soil and the ground to stop the weeds from coming through and keep out toxins and other pests in the ground.

Table of Contents

What to Put at the Bottom of Elevated Garden Bed

1. Cardboard

Cardboard is everywhere, and if you are on a budget, this is the best option for you. Putting cardboard under raised bed is very easy too.

Just spread the board across the bottom, fill it with soil, and you’re done!

However, the cardboard will decompose in 4-6 months. So, it is better to use several sheets of cardboard under raised garden beds to form a thick layer for best results.

Just make sure not to include cardboard with glossy print, for it may release toxins that will harm your plants.

2. Hardware fabric

If you are building your raised garden on concrete, hardware fabric works best as a raised garden bottom liner.

Choose galvanized hardware fabric to avoid sagging and rust over time. On top of it lay a landscape fabric to make a strong and long-lasting garden bed bottom.

How to put a hardware fabric basket under your raised bed:

Using a hardwire fabric on your raised garden bed with bottom provides good drainage and, at the same time, protects your plants from pests such as gophers that can eat all your crops.

3. Plastic

One variation of a raised garden bed is the one with legs. It is easier to reach and is most beneficial if you have back problems. It is ideal to use a light-weight plastic as a liner of a raised garden bed with legs.

How to use plastic as a garden bed liner:

Lining plastic as a base for raised garden bed will protect your plants from toxins that might be present in the frame of your raised garden bed.

Additionally, it is the best material to use if your soil is too dry and you need to keep it moist.

Otherwise, there are other options, including water-permeable material and plastic made of polypropylene fabric that allow better drainage.

4. Mulch

Mulch bottom of raised bed is another excellent option.

Both types of mulch work to prevent the weeds from growing and retain the moisture for your plants. However, organic mulch contains nutrients that are beneficial to your plants in the long run.

For example, mulching with straw in bottom of raised beds is effective in keeping the weeds out and maintaining moisture.

How to add mulch to your raised bed:

What Is the Recommended Soil Mix for Raised Garden Beds

According to Iowa State University Extension and Outreach, light, well-drained soils should be used in raised beds with closed bottom.

You can make a great soil mix of your own by preparing an equal part of topsoil, organic material (leaves, ground bark, composted manure), and coars sand and mixing them all.

Important notes:

Conclusion

A raised garden bed has many benefits. It gives you more control over the soil, protects your plants from weeds and other pests underground, and requires less maintenance. Many materials can be used on a raised garden bed bottom, including cardboards, mulch, hardware fabric, and plastic.

So, what do I put on the bottom of a raised garden bed? It may depend on your budget, the availability of the material near you, and their advantages and disadvantages. We hope we can help you choose based on the information from our post.

Related articles about garden bed:

Happy gardening!

Categories Organization & Repair

A Few Words From the Author

Hi, I am William – Floridayards’ digital content creator. My job is to find answers to all your concerns with thorough research and our team’s expert advice. I will also bring you honest reviews on the best products and equipment for raising your beautiful garden. Please look forward to our work!

– William Golder

What Should You Put On The Bottom Of Your Raised Garden Bed?

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So, you have just built your raised garden bed and now you are ready to fill it and start growing. But what should you put on the bottom? Your raised bed can be part of your garden for years to come, so it is important to start off on the right foot.

The ideal bottom layer should suppress weeds, which help with drainage, improve your soil, keep rodents from burrowing in, and protect your soil from potential contaminants.

Some great materials to put at the bottom of your raised garden bed are cardboard, newspaper, straw, woody material, leaves, grass clippings, rocks, burlap, wool, and hardware cloth.

Each material has its unique benefits for your raised bed and they can be combined to get your garden off to a great start.

Let’s look at the pros and cons of each material so you can decide what will work best to line the bottom of your raised garden beds with.

Should I Line The Bottom Of My Raised Bed?

Of course, you can simply put your raised bed right on the ground to fill it and start growing, and while this is the cheapest and fastest way to get going it might not be the the best option. Wether or not you put something on the bottom of your raised bed depends on your situation, and you should ask yourself questions like:

Benefits Of Lining Your Raised Garden Bed

Building a raised garden bed is a long-term investment that takes a lot of work, so you want to make sure the project is a success. Lining the bottom of the raised beds has several advantages that might be worth the extra time and effort.

Here are some of the benefits of lining your raised bed:

Should You Line My Raised Garden With Landscape Plastic?

There are several reasons that landscape fabric should NOT be used under raised beds.

1: Landscape fabric is not biodegradable

Landscape fabric is thought to be a great option because does not decompose. However, the reason it does not decompose is that it is made of plastic. There is a lot of concern about using plastic in the garden, especially to grow vegetables. If in doubt, it is better to err on the side of caution.

2: It is impermeable to beneficial insects

Earthworms and other beneficial soil-dwelling creatures do not easily pass through landscape fabric. Not only can they become trapped underneath, but they will not be able to travel upwards and your raised bed will not reap the benefits of their assistance.

3: It does not work when buried

While landscape fabric can be very beneficial as a ground cover, it does not when it is buried underground. Any soil on top of the fabric will sprout weeds, and you will end up with a bunch of weeds growing on top of the fabric.

Also, once weeds start growing through the fabric, they are almost impossible to pull out and you will have to remove all the fabric and start over.

If you want to use landscape fabric with your raised beds, consider covering the top of the soil to prevent weeds rather than the bottom.

10 Great Materials To Put Under A Raised Garden Bed

Before your start filling your raised bed with soil, take special consideration about what you put at the bottom. Here are 10 great materials to use to line the bottom of your raised garden bed:

Helpful Tip: If you are using cardboard, newspaper, straw, or other organic matter, have it extended outside the bin by at least 6 inches. This will keep weeds from growing under the edge of the bed and into your soil.

1: Cardboard

Cardboard is the ultimate mulching material for anywhere in the garden, including under a raised bed. It chokes out weeds, keeps moisture in the soil, encourages earthworms, and adds organic matter as it decomposes. Carboard will take about 8 to 10 months to decompose, at which time most of the weeds underneath will be dead.

Cardboard also successfully chokes out tough weeds such as quack grass when a thick enough layer is applied and it is topped with a layer of organic matter such as straw.

Cardboard is free and easy to come by. Try asking your local grocery store, and they will often gladly give you more than you can use.

To use cardboard under your raised bed, remove and staples and tape from the cardboard. Lay down at least two layers of cardboard over the bottom of your raised bed (don’t forget to extend it outside the box), and make sure the edges are overlapped by a few inches so the weeds can’t slip in between.

No matter what other material you put on the bottom of your raised bed, it can always be paired with a bottom layer of cardboard.

2: Newspaper

Newspaper has similar benefits as carboard and makes a great bottom layer for your raised bed. It will smother weeds, is excellent at holding moisture, earthworms love it, and it decomposes into nice compost.

While it will break down a little faster than cardboard, it will still last for most of the season.

One caution of newspaper is some of the ink can contain undesirable chemicals.

Thankfully, most newspaper and printing services are switching to soy-based ink which is safe even for the vegetable garden. Check with your local printing or recycling facility to be sure.

To use newspaper on the bottom of your raised bed, lay down at least 10 sheets with the edge overlapping.

As with cardboard, newspaper can be combined with any other material to form a good bottom to your raised bed.

3: Straw

Straw is a great way to keep moisture in your raised beds while adding organic matter at the same time. While straw will smother weeds on its own, it is better when applied on top of cardboard or newspaper.

Straw adds carbon-rich matter to your raised bed, and the humus that forms as the straw decomposes under the soil will do wonders in the long run.
For best results, add 10cm to 15 cm (4-6 inches) of straw on the bottom of your raised bed.

Be aware that the straw will shrink as it decomposes, so you might have to add a bit more soil to the top of your bed next year.

There are a few considerations when purchasing straw for use in your garden. First, make sure you know your source as a lot of straw comes infested with weeds seeds.

We have noticed in the last few years that anywhere we have used straw from certain farms will sprout thousands of Canadian thistles in subsequent years.

Second, try and source organic straw as this will be free from the harmful fertilizers and pesticides that are used on conventional fields (and no, organic straw does NOT have more weed seeds than conventional farming).

4: Wood, Woodchips, And Other Woody Material

If you really want to choke out the sod below your raised bed, consider lining it with wood planks or old boards.

This creates a more solid weed barrier that will still decompose over time and feed the soil. Avoid using pressure-treated lumber, or glued material such as plywood or OSB as these can leach chemicals into the soil.

Decomposing lumber makes an excellent home for beneficial soil-dwelling bacteria.
You can also put a layer of wood chips on top of cardboard or newspaper. A layer of wood chips that is a few inches thick is excellent at choking out weeds and will retain lots of moisture.

However, too many woodchips can limit nitrogen in the soil and make the soil more acidic, so monitor your soil if you decide to use wood chips.

Adding a layer of wood material, such as branches, twigs, and small logs will also benefit your raised beds. While this will not suppress weeds, the decomposing wood will benefit the soil similar to hügelkultur practices.

5: Leaves

Leaf mould (or decomposing leaves) will really benefit your soil by creating lots of beneficial humus at the bottom of your raised bed. The thick mat of leaves works great at smother weeds that might try to sneak through.

Add 5 to 10 cm (2-4 inches) of leaves to the bottom of your bed (preferably on top of cardboard or newspaper).

You can use leaves from most trees, but avoid using leaves from black walnut and eucalyptus trees as these will inhibit plant growth.

The leaf mat will shrink as it decomposes so you might need to add soil in the following years.

6: Grass Clippings

Grass clippings will form a thick mat at the bottom of your raised bed that will decompose into wonderful humus while choking weeds at the same time.

Apply a layer that is about 5 to 10 cm (2-4 inches) of grass clippings to the bottom of your raised bed.

Make sure that the grass did not go to seed before cutting or you will be fighting grass in your raised bed for years.

Also, a lot of grass that is mechanically clipped can have an oily-gassy smell from the mower, and you might prefer to avoid adding potential toxins to your garden.

7: Rocks

Rocks can be beneficial to your raised bed in certain circumstances but they should be used with caution. When used properly, rocks can improve drainage but they can also cause the ground to become saturated.

If you have very heavy clay soil beneath your raised bed, a layer of rocks in the bottom of the bed can help. The water can settle in the rocks until it filters through the clay keeping the soil in the bed from becoming waterlogged.

However, too many rocks, or if the layer of rocks is too dense, can actually trap water on top of the rocks (similar to a river bed) and the soil will not drain and become saturated.

8: Carpet

Carpet can be used at the bottom of your raised bed, but be careful which kind of carpet you use. Most carpets are made from plastic and will never decompose, potentially leach chemicals, inhibit drainage, and interfere with the roots of your plants.

However, natural carpets made from organic materials (such as hemp, jute, or cotton) can be an excellent bottom layer. These carpets will successfully choke weeds and still be permeable for water and deep roots to pass through. They will generally take a few years to decompose.

You can staple the carpet to the sides of the raised bed to form a solid base, or stick the carpet out past the edges of the bed to keep weeds from slipping in the sides.

9: Wool

There is not much information about using raw sheep’s wool as a bottom layer of your raised bed, but some gardeners have been using wool in their raised beds for years.

There are many benefits to using sheep wool as a mulch and a layer that is 15cm (6 inches) thick will successfully smother weeds.

It is also natural, contributes to healthy soil, and retains moisture while still allowing good drainage. Wool works great on top of cardboard to keep the weeds down.

10: Hardware cloth

If burrowing critters are a plague in your garden, then hardware cloth is the product for you. Hardware cloth is a strong wire mesh used in construction.

It will corrode and break over time, but it will give you at least 10 years of protection from hungry critters digging under your raised beds.

Lay hardware cloth over the bottom of your raised bed and staple it to the sides.

Hardware cloth comes in a variety of different sizes and thicknesses, so check your local hardware store for availability.

Conclusion

Building raised garden beds is not an easy task, so it is important to get it right the first time. I hope this article has given you some ideas on how to line the bottom of your raised bed so you will have a successful and plentiful harvest for years to come.

Cameron Jenkins

Cameron Jenkins moved from the city to a small farm where he lives with his wife and daughters. The farm is divided between the garden, pastures, hayfields, the start of an orchard, and 13 times as many pets as people. Their farm vision is to grow produce and raise animals in unison with nature. When Cameron is not farming (or writing about it) he spends his time playing with his children, reading, cooking, and napping with his pet pig.

What can and cannot be placed in high beds: instructions in pictures

The interest of gardeners in smart beds is getting higher, the degree of discussions and disputes is getting hotter. We decided to bring a little clarity and figure out what must be used to fill the high beds, what is desirable, and what should never be put in it. Join now!

First, let's remember what high beds are and why they are good.

High (and also warm, or smart) is a bed in a box filled with organic waste, plant residues and fallen leaves, which, in the process of decomposition, release heat and warm the earth. Thanks to the correct filling, garden crops in such a bed more easily tolerate temperature changes, develop better and give a higher yield. nine0003

The organic matter that fills the garden bed not only warms the soil for plants, but also turns into a valuable nutrient vermicompost over time. So, it makes smart beds even more efficient.

Benefits of high beds

Let's list the main advantages of high beds, thanks to which they won the hearts of fans of country experiments.

High bed quick guide

  1. Seat selection . Any well-lit place on the site will do. You can place high beds next to a building or fence, but you need to make sure that they are not in the shade. It is recommended to place the bed with the long side to the south - then the lighting of the plantings will be uniform throughout the day.
  2. Trench . Strictly speaking, a trench is not a mandatory element - a high bed can be made right on the lawn. But not to use fertile soil, if it is on the site, would be at least strange. Therefore, deepening the frame of the bed by 20-30 cm looks like a logical decision - and the structure will eventually turn out to be not too high, and fertile soil will come in handy. nine0018
  3. Frame construction . A box for a high bed can be built from improvised materials or you can buy a ready-made metal or plastic structure. If you are making a wooden case, protect it from the inside with a film or impregnation to prevent the wood from rotting. The length of the bed can be any, the parameters of 100-120 cm are considered the optimal width (for the convenience of processing the middle), the height depends on the growth of the gardener and can be from 30 to 80 cm.
  4. Laying layers . The lower layer of the high bed performs the function of drainage, so chopped branches of shrubs and trees, stems of large garden plants are placed in it. The next layer is laid wet fallen leaves, sawdust, turf, tops, unformatted vegetables and fruits, organic waste from the kitchen. Next is a line of green plant residues, which are preferably covered with ready-made compost from above. All valuable organics are sprinkled with fertile soil - and you're done!
  5. Planting or sowing horticultural crops . On high beds, especially in the first year, heat-loving plants that need a lot of nitrogen will feel great: cucumbers, zucchini, pumpkin. In the following seasons, you can plant strawberries, tomatoes, cabbage, carrots, beets, beans and peppers. And at the end of efficiency (about the 4th year), the time will come for unpretentious greenery.

Laying layers of a high bed - what is important to remember

Let's talk in more detail about the fourth point of our algorithm - the correct laying of layers. Let's consider what to put in a high bed in order to get that very double harvest promised to us by "bed building" enthusiasts. nine0003

A fine-mesh metal mesh should be laid at the very bottom of the trench or box - it will protect the plantings from the encroachments of moles and mice, which will surely come to visit. For reliability, it is worth attaching the grid with a construction gun to the bed frame.

Next is the drainage layer. It is needed in order to prevent stagnant moisture and ensure sufficient air exchange in the roots of plants. For this layer, you can use chopped branches and branches of trees and shrubs, brushwood, corn or sunflower stalks. Here you can also add straw and sprinkle everything with wood ash. Drainage height - about 30 cm.

The next layer is not always recommended, but it is worth doing if your soil is light, porous, quickly permeable to water (sand or peat). In this case, after coarse organics, you can lay out wood and paper waste: cardboard, old newspapers, burlap, shavings. Sometimes a layer of sawdust is poured, spilling it with a solution of potassium permanganate. These materials absorb water and gradually release it into the substrate, helping to maintain optimal humidity inside the garden. In addition, thick cardboard prevents the germination of weeds from the soil under the bed. nine0003

How else can you use cardboard and old newspapers for the benefit of the garden? It is recommended to make it about 30-50 cm thick. Plant residues from this year's crop, weeds, turf, fallen leaves, dry grass, kitchen waste and everything that we usually store in a compost heap will go here. The only difference is that this pile will be immediately inside the garden. That is, the process of compost maturation will also go on inside, while releasing heat and providing future plantings with the necessary nutrition. The illustration below shows the possible options for filling the organic layer. nine0003

In order to ensure the ripening of the organic mass by spring, the compost layer is shed with EM preparations that speed up the process.

This is again an optional but desirable layer. If you already have last year's compost at your disposal, lay it in the garden. This will further accelerate the maturation of the lower fresh layer and enrich the composition of the soil. Straw manure or humus can be used for the same purpose.

The logical completion of the "construction" is the backfilling of the upper fertile layer of garden or garden soil 15-20 cm thick. If you prepared a trench to create a warm bed, then simply return the garden soil "to its place". If the soil on your site is unsuitable for growing plants, use a purchased substrate or prepare a potting mix for seedlings yourself according to one of our recipes. nine0003

Raised beds are usually made at the end of the season, and there are at least two reasons for this. Firstly, after harvesting, the summer resident has a lot of organic waste at his disposal, which are great for laying in the garden. Secondly, organic matter must mature to become a nutrient fertilizer, and the winter period is just enough time for this process. The green mass planted in the garden in autumn will turn into high-quality compost by spring and will provide good nutrition to young seedlings and seedlings. nine0003

What not to put in raised beds

Since a raised bed is essentially a well-ordered and organized compost heap covered with earth, the "forbidden ingredients" in both cases will be similar. That is, you can’t put in a high bed what you wouldn’t put in a compost bin: organic matter of animal origin, the remains of raw fish, fruit bones and walnut shells, weeds with seeds, cat litter and non-degradable materials. nine0003

Also, do not put leaves and tops of disease-infected plants in high beds - this will lead to the spread of pathogens to your future plantings. To prevent such a scenario, some gardeners use fungicides: they spill the "dangerous" layer with a solution of Fitosporin, HOM or SCOR and hope for the best. But is such a risky game worth the candle - you decide!

If you have long wanted to experiment with beds in your country garden, now is the time! Use our tips and you can get a high yield with less effort and without harm to health. nine0003

How to make high beds: very useful ideas

You will be surprised at your past doubts - whether to make high beds in the country ... Your back will be grateful to you - you just bend over a little to care for the garden. Your knees will thank you - you can just sit on the edge of the garden and work on your garden. Your plants will thank you - no more competition from weeds or nearby fruit trees. Your land will be grateful to you - you do not trample it down and ennoble it with humus. Your high-bed garden can look beautiful, comfortable, and reward you with a generous harvest. nine0003

1. First we have to mark the place for the beds. The usual width of the beds is 1.2 m, the length can be any. We mark the rectangles of the desired size on the ground with sand.

2. We collect high beds. The high bed has no bottom and consists of posts with grooves on all four sides and boards with corresponding grooves. You can buy ready-made garden fences or make your own. For fences, it is better to take hardwood, because. conifers emit resin, which can have an unnecessary effect on soil composition. We check the horizontal installation of the garden box with a level. nine0003

3. Extend the high beds. Because Our beds are modular, we can extend our beds from any side with another module.

4. How to protect the high bed from rodents. Even if you have not encountered moles and other underground garden pests in your summer cottage, it is better to provide protection for your garden right now than to unsuccessfully fight these rodents later. At the bottom of each box we put a metal mesh so that it goes a little to the edges of the fences. nine0003

5. How to protect the soil in a high bed from being washed into the main soil. To do this, we use ordinary packing cardboard in two layers so that it covers the entire bottom of our garden box. If there are not enough whole pieces, we use scraps of cardboard - we fasten them with a stapler with the main piece so that the cardboard at the bottom of the box does not move when the soil is poured.

6. The soil for raised beds should be light, crumbly and fluffy. You can easily check its quality by poking your finger into the ground - if it sinks to the third joint, this is the norm. To improve the composition of the soil, you can add peat or compost. We pour the soil into the garden box, check its horizontal level, water it to compact it a little. During the season, we will need to add a little soil. nine0003

7. High bed irrigation system. Along the contour of the high beds, it is planned to fix a garden hose with watering nozzles: we need 90 and 180 degree splitters.

8. High bed trellises. Because the ground in the high bed is loose, then it will not be possible to install a trellis in it, so we fix the trellis from pvc pipes into the ground next to the garden box. On the trellis we stretch nets for climbing plants - cucumbers and beans. For tomatoes, we install light supports made of steel rod. nine0003

What you need to know when building a high bed.

1. Try to protect high beds from strong winds and heat by creating partial shade with flower trellises or tall shrubs.

2. The long side of the bed should face south so the plants will be evenly lit, otherwise the taller plants will shade the others.

3. The planting density on the high bed is twice that of the regular bed. So plants fight weeds and create a humid microclimate with foliage. nine0003

4. High beds with borders will allow older people or people with back problems to take care of the garden.

5. High bed - warm bed. Such a bed warms up faster in the spring, and if you make a mini greenhouse on its basis, it will surprise you with an early and generous harvest.

6. Divide a long, tall bed into square segments with cross braces to reduce soil pressure on the side walls of the bed.

Fencing for raised beds.

1. Wood fences are most often used for clear beds. There are a few points here - do not use used wood, especially sleepers, which can contain harmful chemicals. Do not treat fresh wood with wood preservatives unless you are sure they are completely environmentally friendly.

2. Wattle fence for raised beds. For all its environmental friendliness, such a fence has three significant drawbacks - the soil in the bed dries quickly from the wind, proper thermal insulation of the bed is not provided, the soil can spill out through the cracks. Everything is fixable - use a layer of double cardboard around the inner perimeter of the fence. Environmentally friendly, the air gap between the sheets serves as thermal insulation, the earth no longer spills out. nine0003

3. As a fence for a high bed, you can use a metal profile, including from an old roof or fence.

5. You can make your own high bed railings out of brick or concrete. This is a very good option, but keep in mind that concrete will affect the acidity of the soil in the garden for 2-3 years.

6. The best raised bed railings are plastic. They do not emit anything of their own into the soil, excellent thermal insulation, long service life and the ability to set any shape of the beds, unlike standard rectangles of beds with wooden fences. nine0003

7. Fences for a high bed from improvised materials. You can make the sides of the beds from bottles laid like bricks on a concrete mortar.

Why high beds are needed.

High beds allow you to increase the area under the garden. you can use inconvenient slopes or poor or weedy soil. Raised beds provide an environmentally friendly way to deal with weeds and soil erosion.

These beds warm up faster and produce an earlier harvest. They allow more economical use of moisture for irrigation. nine0003

Various types of raised beds.

In addition to the traditional raised bed with high sides, there are several other types of raised beds.

1. Circular raised bed. It consists of a round frame, in which there is a path to the center of the bed. This form of high beds is also called the "keyhole".

Branches, roots, paper, compost are placed at the bottom of the beds. In the middle of the bed there is a tunnel for fresh organic waste and water.

This design of the bed provides the right moisture and constant enrichment of the soil.

2. High bed without fences. When arranging such a bed, the trunks of trees (not conifers), branches, roots, snags are laid in the ground at a shallow depth; the second layer is this sod removed from the place where you make the bed, laid down with grass; the third layer is 20-30 cm of the main soil mixed with humus.

To irrigate bulk high beds, an irrigation irrigation system is used when water comes from a ditch between the beds - a good option for gardens flooded in the spring, or you can use a drip irrigation option when water enters the bed from mini terraces. nine0003

The paths between the beds are covered with straw or large sawdust. Never step on the ground in a high bed - this will compact it, and it will be more difficult for plants to receive moisture and nutrients.

High beds of this type can be used not only for a garden, but also for growing shrubs and fruit trees, if you have problematic soil for them in your summer cottage. The service life of such a bed (until the first tree layer with trunks completely rots) is 20-25 years - this period is enough for any fruit tree. nine0003

Spare no space for paths between high beds - so you can always drive there with a garden wheelbarrow both for harvesting and with a new portion of humus.

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