How to Build a Raised Garden Bed (2024)

FAQs

What do I put on the bottom of a raised garden bed? ›

Cardboard and Wood Chips: Layering cardboard at the bottom of your raised bed is an effective, cost-efficient way to suppress weeds. It eventually breaks down, enriching the soil with carbon. Wood chips can be added on top of the cardboard as an additional layer for weed control and moisture retention.

Cedar and redwood are naturally water-resistant but can be expensive and hard to find. Hemlock, fir and pine are suitable materials for raised beds but aren't very long lasting. Pressure-treated lumber is also an option, but it's been a controversial topic for many years.

On average, a DIY raised bed constructed from wood will cost $25 to $50 per square foot. To have a wooden raised bed constructed and installed for you, budget for at least $100 per square foot. (Find a kitchen garden company in your area.)

They should have at least 8 inches of soil depth to accommodate the root systems of plants, because the majority of plant roots require 6 – 8 inches of soil for healthy root growth. A depth of 8 – 12 inches will suffice for most gardening situations.

The fact is, landscape fabric is not a necessity if say, you want to control weeds because the confined space makes it easier to control weeds. But, you can use landscape fabric as a raised bed liner for other reasons, such as preventing soil erosion or improving the life of the raised bed itself.

It acts as a physical barrier to block out pernicious weeds. Usually, 2 – 3 layers of cardboard will suffice, though you may want layers in more weed-prone areas. The damp environment created by the cardboard is conducive to earthworms and other beneficial soil microorganisms.

Avoid using older types of wood treatments such as CCA, creosote, and Penta-treated lumber. Research from Oregon State University showed that pressure-treated lumber does increase soil copper concentrations by a minor amount, but only within 1 inch of the raised-bed edge.

He stated in a bulletin titled, Treated Wood in Raised Bed Gardening, “Scientific evidence and data have shown that using pressure treated wood for raised bed or box gardening is safe to adults and children in terms of the plants grown and used in these containers.” He further explains, “All chemicals in consumer ...

As a final reminder, avoid lining your garden beds with plastic. Doing so prevents drainage and could drown your plants' roots with too much water. If you have a weed and pest problem, consider installing a combination of metal mesh and fabric or hardware cloth and cardboard to address both issues simultaneously.

Pallets are a cheap and easy way to create a raised garden bed. You can usually find them for free or for a low price. Just stack them on top of each other, and fill them with soil.

What is the cheapest way to make raised beds? ›

Raised beds made of cinder blocks or concrete blocks

Cinder blocks and concrete blocks are very inexpensive (typically $2 to $3 a piece at home improvement centers), and they make it really easy to build the outline of a raised garden bed.

Raised-Bed Garden Cost per Square Foot

If you're DIY'ing your garden installation, expect to spend anywhere from $25 to $50 per square foot of garden space for wood raised beds. Stone, brick, and steel will be more expensive.

A: You should avoid putting rocks in the bottom of your garden bed. A common myth is that this will improve drainage. Instead, this can actually increase water saturation levels as well as allow gravel to mix in with your soil, which can prove very difficult to remove later on.

As a rule of thumb, a 4'x8' raised bed that is 6 inches deep requires approximately 8 bags of soil while a 4'x8' raised bed that is 12 inches deep requires approximately 16 bags of soil.

Most garden vegetables will grow well in raised beds. Try growing lettuce, greens, radishes, and strawberries. Bush type vegetables, such as tomatoes, cucumbers, and beans also do well in raised beds. You can install trellises for vegetables that need support, like some tomatoes and beans.

You can line your raised bed to make it more durable and to prevent toxics from leaching into the soil. For lining, use landscape fabric found at garden supply stores or cloth fabric from clothing. Avoid non-porous plastic, as it can retain too much water and discourage beneficial insects and worms.

One of the best things to put at the bottom of a planter for drainage is broken pieces of pot. You can use any unwanted plant pots or chipped crockery for this – simply smash them up into small to medium-sized pieces. Adding a layer of broken pieces of pot like this will prevent compost loss out of the drainage holes.

Adding rocks to the bottom of a raised bed makes it challenging to amend or improve the soil over time. It restricts access to the lower layers and can impede the addition of organic matter or nutrients. Over time, rocks will get mixed in with your raised bed soil, not cool!

A strong and stable base is essential for the health and productivity of your raised garden bed. By using the right materials, such as gravel, landscape fabric, sand, compost, cardboard, or soil, you can create a well-draining and nutrient-rich foundation for your plants.