How to Build Raised Bed Gardens
Necessary Tools for Building Your Beds
- Electric drill
- Small sledgehammer or heavy headed hammer
- Spade or borer bits 1/16 to 1/8" larger than your spikes
- Eye protection
- A saw- for timbers use a reciprocating saw or chainsaw, depending
- Chisel and heavy hammer- for etching and cutting blocks.
- Tin snips for cutting hardware clothe
- Bolt cutters for cutting rebar (If you are using rebar spikes, and they aren't pre-cut)
For folks who want a different type of landscaping or an easier way to garden, raised bed gardens are very economical and easy to build. It's a fact that a good landscape can add up to 10% to your home's resale value and raised beds can be used as a landscaping method. You can grow what ever you want in them; tomatoes, onions, garlic, peppers, corn, pumpkins, melons, strawberries, etc. The list is too long to write.
The first step is deciding where you want your beds to be. You can build them alongside a building or use them as a border in an open landscape. You're only limited by your imagination. One thing to keep in mind, however, is whether or not you want them to be level or run with the contour of your landscape. Leveling them may require digging out part of your landscape to allow them all to be on the same plane. It's more work, but it can look amazing after it's all said and done. One of the beauties of using raised beds is that you don't need to worry about the quality of soil your building on, your beds will be filled with quality soil for growing. If you have a problems with moles or gophers, however, you may want to lay hardware cloth down before you set your timbers or blocks. Hardware cloth is made of welded wire that has very tiny holes in it. It's not the same as landscape fabric. Once the beds are built, the cloth will keep gophers and moles from burrowing up into your beds.
Once you've decided on the location, you should figure out how much space you'll need to build your bed(s). It's important to note the the ease of use is negated if you can't reach the middle of the beds, so keeping them between 5 and 6 feet wide will make them easier to use. This might mean that you need to build more than one, depending on the length and shape you're going for. You can build them in any shape you care to. The only thing is, odd shapes require more cutting of materials to build the bed. The material you use may dictate what shape you go for. Timbers can be difficult to cut, making intricate shapes that require more cutting very difficult. Blocks are easier to use, but it depends on your personal preference on what looks better. You can use used rail road ties, landscape timbers, landscaping blocks, concrete building blocks, etc. to build. Each have a different look to them, so if you plan on landscaping around them, keep in mind the look you're going for.
Once you've where your building as well as what materials and how big of bed or beds your building, you can start preparing your ground. If you want to level out an area and have quite a bit of ground to level, you may want to rent a small backhoe or end loader to dig out the area to be leveled. If you're not leveling the ground, you can begin to lay out your material to get an idea what your beds will look like before you make it permanent. Once you've laid out your hardware cloth (if your using it, and I would highly suggest it), you can lay your block or timbers down on top of it to begin forming the bed. You don't need to kill off any grass in or around your beds. The dirt you put in the bed will take care of what's inside the bed and mulching or laying patio block around the bed will take care of outside of the bed.The approach you take to lay and fasten your materials depends on what your using, blocks or timbers.
Timbers are great way to go, because they cover more length when building rectangular beds. Smaller timbers can be easier to cut with a hand saw or reciprocating saw, but rail road ties require a chainsaw to cut. Heavier timbers tend to move less over time, but staking them correctly will take care of any problems you may have. L
- lay down your first layer of timbers, usually there will be no less than two, but you can use up to 4 or 5 depending on how tall you want your beds to be and what kind of timbers your using. The 3x5 timbers that are commonly seen with rounded sides are not the greatest choice for raised beds because they are so narrow. They tend to bow out over time because of the soil. Alternating your pattern from the first layer will help strengthen your bed to prevent the sides from bowing out.
- Next, drill down through the timbers to stake them into the ground. As a general rule, you'll want to drill where ever two timbers meet, no matter the layer. This is why staggering timbers is important. Where two timbers meet on one layer, another layer has a solid timber, making it stronger. For the drilling, you'll need a borer or spade bit that is adequate for the size stake you are using. There are stakes made for staking landscape timbers, but I would recommend using rebar because it is just as effective and much less expensive.
- Cut the re-bar at least 1.5 feet longer than the height of your timbers. For example, if your wall is 2 feet high, your re bar stake should be 3.5 feet long. This allows for them to anchor securely into the soil. Your bit should be just larger than your spikes, so if your spikes are 3/8" thick, you'll want a bit size no less than 7/16". It is important to keep the holes close to the same size as the spikes though, because this allows for a tight fit. The tighter the holes, the more you'll need to drive the spikes in, which is where a heavy hammer or small sledge hammer will come in handy.
When using block, you'll need a block cutter or a chisel and hammer. The block cutter may be too expensive for one use, but they can be rented. A chisel and hammer is more economical, but more time consuming.
- To use the hammer and chisel, measure the length of the block needs to be cut to. Then use the corner of the chisel and etch a shallow groove in a line at the spot where your block needs to be cut.
- Once you've etched the block, place the chisel in the channel and hit it with the hammer firmly. One or two strikes with the hammer and the block should break at the etch mark. When using retaining wall block, this is especially useful.
- Using the same method as with timbers, set your block in the shape you plan on building the bed. Once you've laid them out and have the shape that you want down, you can start layering your blocks. You should stagger the block as well to provide stability in the wall. If the wall is to be more than 3 feet tall, retaining wall grid will be necessary, which should be available at the same place you bought the blocks. It is used to tie the blocks into the soil to keep them from bowing and eventually toppling over. It isn't common to see raised bed gardens over three feet high.
- When using concrete construction blocks, you can use the mortaring method used in construction to fasten blocks together. However, a much cheaper method to fasten blocks used in raised beds is landscape block adhesive. It is a specially designed adhesive to bond concrete to concrete.
After building your walls, you'll need to fill in your beds with soil. You can use pretty well any soil to fill in the bulk of your bed. Sand isn't suggested because your raised beds will drain better than the soil around them anyway. Usually, any soil removed in the construction of the beds is usable for back-fill. Otherwise, dirt can be brought in or taken from another area of your property. The top 4-6" should be composed of topsoil/peat dirt and organic compost or peat moss. This gives your plants a good soil to develop in and helps keep nutrients around the root system of your plants, especially in the beginning. Blending of the soil can be done with a shovel, but the most effective method is with a small rototiller.
Once your beds have been completed, you can begin planting what you want in them. Using companion plants would be my suggestion to you to get the most of your garden. Keep an eye out for dry soil, as this can become more common in raised beds than conventional gardens. Your raised bed gardens will provide you with decades of use as well as a much more ergonomic gardening experience. Happy gardening!
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