How To Build Raised Beds For Gardening

What are raised beds for gardening?

A raised bed is exactly what it sounds like. It’s a bed that’s elevated above the ground. This can be achieved in a number of different ways. You can use stone, bricks, concrete or wooden blocks. Whatever you decide on, you can be sure that it’ll be more stable than a traditional raised bed. This increased height allows you to grow taller plants and, in turn, larger harvest yield. This is because taller plants have a greater reach to gather sunlight. They can also grow larger roots that are able to reach into the soil bed for better nutrient absorption. This is especially helpful for heavy feeders like tomatoes, peppers and potatoes.

Benefits of using raised beds for gardening

Greater yield

• Different species of plant, like tomatoes, grow larger yields when grown in raised beds.
• This is because they have a greater reach to the light, water, and nutrients in the soil. 

Durability

• Because raised beds are elevated above the ground, they are more durable.
• This means they can be used for longer without the need for repairs due to weather erosion.
• If a raised bed is built right, there will probably be no need for repairs for years to come! 

Cleaner

• Raised beds are cleaner than traditional beds because they’re elevated above the ground.
• This allows rainwater to flow underneath and away from the beds, keeping them clean.  

Stronger

• Raised beds are stronger than traditional beds.
• This is because they’re elevated up off the ground. This makes them more durable and resistant to weather erosion. 

Easier to water

• Raised beds are easier to water because the water flows underneath them and away from the beds.
• This is particularly beneficial in regions with heavy rains.

Better drainage

• Raised beds are better at draining because they’re elevated above ground level.
• This means they’re able to shed the excess water away from the soil, preventing it from drowning the roots of your plants.

How deep should a raised garden bed be?

Raised garden beds should have at least 8 inches of soil depth to accommodate the root systems of plants. (Roughly speaking, most plant roots require 6 – 8 inches of soil for healthy root growth, so a depth of 8 – 12 inches might suffice for most gardening situations).

(Note that you can actually build a raised bed be installed on a concrete surface, such as a patio or even a balcony! You might need to opt for a slightly taller one, i.e. the 6" one might not be the best option).

The required depth of soil depends on your plant choices. Here’s basic overview of what you can grow in beds of various depths:

Plants suitable for 6” raised beds

• Arugula
• Leeks
• Lettuce
• Onions
• Radishes
• Spinach
• Strawberries
• Basil
• Chives
• Cilantro
• Dill
• Mint
• Oregano
• Parsley
• Thyme
• Marigolds (and similar annual flowers)

Plants suitable for 12” raised beds

• Beans
• Beets
• Borage
• Broccoli
• Brussels Sprouts
• Cabbage
• Calendula
• Cantaloupe
• Carrots
• Cauliflower
• Collards
• Cucumbers
• Garlic
• Kale
• Lavender
• Nasturtiums
• Rosemary
• Sage
• Summer Squash
• Swiss Chard
• Turnips

Plants suitable for 20” raised beds‍

• Artichokes
• Asparagus
• Eggplant
• Okra
• Parsnips
• Peppers
• Pineapple
• Sage
• Sweet Potatoes
• Tomatoes
• Watermelon
• Winter Squash

How to build a raised garden bed

Building a raised bed for gardening is actually quite easy. All you need to do is follow a few simple steps and you’ll be up and running in no time! 

Step 1

Decide on the type of bed you want to build. There are a few different options to consider when it comes to building a raised bed. First is the material to use: for a first garden bed, go with a cost effective option such as lumber, concrete blocks or even a modified animal trough.

If you want to build a rectangular raised bed, you can either use a concrete base or a brick base. If you want to build a circular raised bed, you can either use a concrete base or a block base. If you’re unsure what type of bed to build, simply start with a rectangular raised bed. This is the most common bed type and is suitable for most types of plants. 

Step 2

Find a location for your raised bed. Having a central location for your raised bed is the best option. This allows you to easily access from either side to water and maintain it easily. It both allows your plants to reach adequate levels of sunlight and creates ready access for the gardener.

Also, consider what you will eventually grow in your bed, as well as the planting layout you have in mind. You probably want to lay out the beds so they are horizontally facing south. If your bed is aligned with the ends facing south, you may have taller plants in the front block out the sunlight for the smaller plants in back.

Step 3

If you haven't used the ground for gardening, the soil in your growing spot should be ‘turned over’, i.e. you want to dig it up to a depth of around 16” (40 cm). Check the composition of the soil. Pull out any rocks, and keep an eye out for any roots which may be growing beneath. These roots can take away from the fertility of your soil. Pull any roots back towards their source.

You might want to leave the dug up soil piled up squarely in the center, so you can easily build or set the bed in place around the soil without having to move the soil around yet again.

Also, with the dug up soil, it'll be easier to level the growing site. (Yes, making sure the site is level is quite important, as it makes watering the plants evenly much easier).

Step 4

Build the actual bed!

• Cedar is often best wood to use for garden bed, as it's naturally rot resistant. Western red cedar is commonly used, but white or yellow cedar and juniper are also good options for raised beds.
• To make it easy to reach the center of the bed from either side, it's best to make the bed no wider that 4′ (1.2m) across, and to avoid having to step on the bed since this compresses the soil.
• The bed can be any length as long as cross supports are installed every 4′ – 6′ along the length of the bed to prevent the beds from bowing out. If you just have the space, longer beds are preferable.
• When stacking up and fastening the wood, again, bring out that level to make sure the construction is decently level.

Step 5

Regardless of the depth of your bed, here's how to prepare the raised bed for planting:

• Lay flat cardboard (remove any tape first!) on the bottom of your container and wet it down with your hose. (If your garden has severe borrowing pests such as moles, you might even want to add a layer of mesh across the bottom).
• Add debris from around your space. Leaf litter, sticks and twigs and even larger branches or logs are all good options. 
• Lay down prepared compost to fill in the spaces of the sticks and leaves 
• Lastly, add a layer of top soil leaving one to two inches of space between the soil and the top of the container. (It's ideal to use 50% screened topsoil made of healthy loam, and 50% compost. Alternatively, a 1/3 peat moss, 1/3 vermiculite, 1/3 compost blend. Gear this towards what you aim to plant in your bed).

These steps accomplish several things at once: By adding cardboard, you lessen the chance of weeds coming through the ground into your bed. By adding leaf litter and branches, you add nutrients to the soil but also space, which reduces the amount of top soil a gardener will need to purchase. 

Step 6

Add plants!

Step 7

Make sure you water your raised bed thoroughly, but not so much that water is pooling. An easy way to check if your raised bed needs more water is by inserting your finger into the soil up until the second knuckle. If the soil is clinging to your finger and damp, no need to water. If the soil is dry, it’s time to water once again.

If you are going to build several beds, leave a generous width between beds for the pathways. It helps when pathways between beds are wide enough for your wheelbarrow. It might even make sense to mulch the pathways.

And there you have it! Your raised bed is now ready for use. Once it’s built, you can simply fill it with seedlings or plant seeds directly.  Once they’re planted and watered, they’ll be ready to grow.

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