What is a Raised Garden Bed? (Plus When to Use Them)


Are you just hearing about raised garden beds for the first time?  If so, then you might not know what all the fuss is about.  You are probably wondering what a raised garden bed is and when you should use one.

So, what is a raised garden bed?  A raised garden bed is a structure built to hold soil at an elevation of at least 6 inches (15 centimeters) above the ground.  A raised garden bed can be made from wood, stone, plastic, or recycled materials.  A raised garden bed is used for growing flowers or vegetables.

There are many benefits to planting in a raised garden bed, for both you and your plants.  Let’s start with a bit more detail about what a raised garden bed is.  Later on, we’ll get into the benefits and when you should use a raised garden bed.

What is a Raised Garden Bed?

A raised garden bed is a structure built to hold soil for growing flowers or vegetables.  A raised bed can be made from wood, stone, or plastic.  You could even use recycled materials to build a raised garden bed!

supported raised bed
Wood is one material you can use to build a raised garden bed. Stone and plastic are also possible.

A raised garden bed holds soil at an elevation above the surrounding ground.  Most raised garden beds are at least 6 inches (15 centimeters) high, but some are 36 inches (90 centimeters) high or more.

According to Wikipedia, plants in a raised bed can create a microclimate when they are grown close together.  This helps to retain moisture for the plants, and also helps to stop weeds from growing.

When to Use a Raised Garden Bed (Benefits of Raised Garden Beds)

Raised garden beds have several benefits for you and your plants.  Let’s go over some of those benefits, and when you might want to use a raised garden bed.

Warm up Soil Faster

The soil inside a raised garden bed will warm up faster than the surrounding ground.  The reason is the difference in sunlight exposure.

When sunlight hits soil on the ground, the soil is only warmed from the top.  When sunlight hits a raised garden bed, the soil is warmed up from the top and from all four sides.

This is useful if you live in an area with a short growing season.  With a raised garden bed, you can put cold-sensitive plants outside a little earlier in the season.

This will give them more time to fully mature before harvest.  It will also reduce the chances of a late spring frost damaging or killing your plants.

Improve Soil Drainage

If your soil drains poorly, then it will stay too wet for too long after watering or heavy rain.  This can lead to root rot, which will kill your plants.

Raised garden beds improve soil drainage, thanks to their elevation above the surrounding ground.  Due to gravity, water naturally flows from high elevation (a raised garden bed) to low elevation (the ground under a raised garden bed).

A raised garden bed also gives you control over the material you use for growing.  That means you can add compost or use sandy soil to further improve drainage.

A raised garden bed is useful if you live in an area with a long rainy season and heavy clay soil.  In that case, you may even need to take extra steps to improve soil drainage.

You can learn more in my article about how to improve drainage in raised garden beds.

clay soil
Clay soil drains poorly and retains water for a long time. A raised garden bed can help to improve soil drainage.

One drawback of a raised garden bed is that it may drain too fast, especially in warm, dry climates.  If this happens, use a layer of mulch over the soil to retain moisture.

If the problem persists, check out my article on how to treat dry soil.

Keep Soil Loose (Prevent Soil Compaction)

If you walk on garden soil, it becomes compacted over time.  Compacted soil has particles that are packed too close together.

This type of soil holds less air.  There is also less space for water to move through the soil.  Compacted soil is also more difficult to work when planting.

If your raised garden bed is narrow enough, you can access the whole bed from outside of the bed without walking on the soil.  Usually, this means making the bed no more than 4 feet (1.2 meters) wide.

Keep Pests and Weeds Out

A raised garden bed acts as a barrier for pests that want to get into your vegetables.  It also makes it more difficult for weeds to gain a foothold.

Pests will need to climb the edges of a raised garden bed to get at your plants.  It won’t be impossible for them to get in, but it does mean that they will have a harder time getting into your garden.

Hopefully, those pests will choose to move on to greener pastures and easier pickings!  If not, a liner in your raised garden bed will make it harder for gophers, moles, and voles to feast on your plants.

You can learn more about raised garden bed liners in my article here.

mole
Use a raised garden bed liner and tell the moles to take a hike!

Ergonomic and Adaptive Gardening (Improved Garden Accessibility)

A raised garden bed is much more accessible.  It makes gardening easier for anyone who is handicapped due to age, injury, or disability.

To have a successful garden, you need to dig soil, sow seeds, apply fertilizer, pull weeds, and harvest vegetables.  If your raised garden bed is at the proper height, you can do less bending, kneeling, and stooping.

You can make a raised bed any length you want.  However, as mentioned earlier, the width should be at most 4 feet (1.2 meters).  That way, you are at most 2 feet from any place in the raised bed that you need to reach.

You can also use a raised bed to level out a sloping yard.  In that case, you will need to build a custom raised bed, rather than using a kit.

Finally, you can install a raised garden bed on any surface you like: grass, patio, or concrete.  You can learn more about building a raised garden bed on grass in my article here.

Prevent Soil Erosion

If your yard has a steep slope or is prone to flooding and wind, then erosion could pose a serious problem.  Erosion happens when natural forces (such as wind or water) wash away soil from your garden.

A raised garden bed prevents soil erosion by leveling out an incline in your yard (as mentioned above).  It also helps to keep soil inside the raised bed when it rains, and prevents the wind from blowing soil away.

You can learn more in my article about how to prevent soil erosion.

How Deep Should a Raised Garden Bed Be?

Most raised garden beds are at least 6 inches (15 centimeters) deep.  The Old Farmer’s Almanac suggests that 12 inches is the ideal depth for a raised garden bed.

However, some raised garden beds are 36 inches (90 centimeters) deep or more.  There are several good reasons to make your raised garden bed deeper.

First of all, the roots of many plants grow deeper than 6 to 12 inches.  For example, the following plants have roots that can grow over 2 feet (60 centimeters) deep:

  • Asparagus
  • Rhubarb
  • Tomatoes
asparagus plants
Asparagus plants can have deep roots, so they might need a deeper raised garden bed.

A deeper raised bed leaves more room for the roots of these plants to grow.  Without enough space for roots, your plants may not produce the vegetable yield you want at harvest time.

Also, a taller raised bed allows you to leave some room at the top of the bed.  This extra space means you will have room to add mulch later in the season, if you wish.

In addition, a taller raised bed is helpful when growing potatoes.  The reason is that you will need to pile soil at the base of the potato plant as it grows (this is called hilling).

Just remember that if your raised garden bed is too deep, it may buckle or collapse.  The lots of wet soil can cause the sides of your raised bed to buckle under the weight.

When you decide how deep to make a raised garden bed, there are many different factors to think about.  You can learn more in my article about how deep to make raised garden beds.

What is the Best Material for a Raised Garden Bed?

You can make a raised garden bed out of stone, plastic, or wood.  There are many different materials to choose from within each of these three basic types.

For example, you could use bricks, pavers, concrete, or rocks to build a stone raised garden bed.  Redwood, cedar, and cypress are fairly durable as wood for raised garden beds.

You can find out more in my article about the best material for raised garden beds.

containerized raised bed
You can make a raised garden bed out of recycled materials or even logs and sticks, as shown here.

Conclusion

Now you know what a raised garden bed is.  You also know all about the benefits of raised garden beds and when to use them.

I hope you found this article helpful – if so, please share it with someone who will find the information useful.

Do you want to build a raised garden bed yourself from scratch?  If so, do yourself a favor and check out this article on how to Design & Build a Raised Garden Bed from Homestead and Chill.  There are some great ideas and information here!

jonathon.david.madore

Hi, I'm Jonathon. I’m the gardening guy (not guru!) who is encouraging everyone to spend more time in the garden. I try to help solve common gardening problems so that you can get the best harvest every year!

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