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Advice On Building Raised Beds

I'm looking for some advice on building a raised bed that will be pretty sturdy and long lasting with the following points

- It's going to be a bit of a biggie. Roughly 2 to 3 foot in width and similar height but the length of it will be in excess of 20 foot as it will run pretty much the length of the garden.

- It will run alongside the garden fence. Obviously I can't just use the fence as the back wall of it but given that side will be completely out of view I really just want something that will be sturdy and long lasting enough to support the soil weight without being too wide or expensive.

- Front walls will go directly on top of existing slab paving. The end walls will go on top of the existing soil flower beds and will butt up to decking either side so doesn't give me much scope for putting a foundation in.

I like the idea of old wooden sleepers or timber but have no idea how much it would cost a for a bed of that size(a quick google seems to show me that sleepers aren't really cheap!). Any alternative and more cost effective materials I could use or recommendations on where to find cheap sleepers?

If I did go with sleepers could I simply pile them up and rely on the weight to hold them in place or would I need to join/secure them in some way?

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Re: Advice On Building Raised Beds

Why do you need it 2-3 feet high? That is very high and will take a ton (literally!) of soil to fill it (actually probably more than one ton, given how big it is). When I built similar raised bed, completely on top of a concrete patio, I made it 16" tall. That was plenty for growing even tomatoes.

I have built them out of 4x4" pine fence posts and out of landscape timbers. The 4x4's are better wood and probably longer lasting, but the landscape timbers are cheaper.

Yes, you absolutely need to join them, otherwise it will all just fall apart.

Here's a thread where I posted pictures of my current raised beds of landscape timbers and one of one of the beds of 4x4's that I made at my previous house: ... ds#p383540

They are stacked (alternating stack), drilled through the stack and steel rebar pounded into the holes, at every corner and in the middle of the sides. That makes them very solid. I seal the wood inside and out before filling them, which I think helps them last longer. The 4x4's had lasted 12 years at the time we sold the house and were still going strong.

The first place I built raised beds, I just used flat boards. Even though I used angle irons and lots of braces, within three years they were all falling apart.

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Re: Advice On Building Raised Beds

Here are a couple more points to consider before embarking on this grand project :D

- Unless you are very tall with very long arms, 3 ft wide bed would be difficult to reach all the way across from just one side.

- it's always important to consider what's on the other side of that fence especially when you are planting edibles. If you have no control over what is done to the adjacent ground, it will be best to have a buffer zone -- a mulched path for example -- between the fence and the veg garden bed. Even better if you can also plant some expendable ornamental buffer shrubs or plants/vines that will catch and act as warning if they start to die and/or phyto-remediate toxins along the fence as well.

- if the bed design becomes 3 ft wide with access from both sides -- trust me -- you will want an access path to break up that 20 ft stretch so you won't have to go ALL the way around to the other side. :wink:

Seriously, though, if you plant things like peas and beans, cucumbers.... it REALLY helps to be able to look and harvest from both sides.

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Re: Advice On Building Raised Beds

It is common for people to put a bed along a wall or fence but it is often a mistake. Been there, done that. I built my bed with hollow wall tile, that was dry laid and stabilized with rebar and stones in the tiles topped with soil for planting the tops or cap stones. The tile works fine. However my fence is a 6 ft hollow tile wall. It faces east but because of the wall there was shadows cast on the bed till 10 a.m. The sun heated the wall and most of the plants grew tilted away from the wall. Only the vanda and night blooming cereus actually clung to the wall because they don't mind a hot wall. Cleaning the bed out was hard because I did have to go into it to clear it. Now I only use it for potted plants, mostly citrus trees. If it was a permeable fence the plants would have ended up in the neighbors yard.

A better plan is to move the bed out at least the height of the fence away from it 5-6 ft. That will give you a maintenance path all around the bed. A 4 ft wide bed can be worked from two sides. You can put a border bed or turf along a chain link or open fence but you still need for it to be able to be maintained so it won't encroach on the neighbors yard. Depending on your relationship with your neighbor, I would not plant veggies along the fence line because you don't know what your neighbor is using in their yard, so non-edibles and plants you won't miss can be planted there. I like using hollow tile because it is durable and will not rot. I live in Hawaii where wood in the ground will be eaten by termites or rot from the rain. If you build it 2 hollow tiles wide and two tiles high you will have a about 4 ft wide bed more or less. The tiles that form the long side of the bed will make it a total of 3 tiles wide (approx 4ft if tiles are 16 inches long). I would make the beds 8 ft long and you may be able to get two beds along that length. 8-10 is a comfortable length to work with because otherwise you would have to walk through the bed or go the long way around them. If you put two rows of beds in parallel to each other you can have 4 beds in a 10ft x 20 ft space.

Having different beds can be helpful for rotation and for plants with different needs. Tall plants like corn, okra, tomatoes will take up the entire space and have long maturities. Greens like lettuce, Asian greens, spinach have short maturities of about 50-70 days and they like similar conditions so it is easier for them to be in the same bed. They are short plants so would be blocked by the larger plants unless that is what you are going for. Intermediate maturities and larger plants like cucumber (on a trellis) zucchini which takes up a lot of space (36 inch circle), cabbages, squash, ice box watermelons, beans need more room

Some plants will need a trellis so they are best in a bed that is farthest to the North and the bed should have a permanent or foundations to accept a trellis. If you want winter protection to extend the season a bit longer. put in anchors so you can make PVC hoop houses for row covers.

I have a CRW trellis for my tomatoes. But when the tomatoes are taking a break, I use the trellis for beans, peas, and gourds. My home veggie garden is small it is an 8ft x 16 ft oval. It was a rock garden that was converted after we bought the house. I use stepping stones to divide it and provide a pathway, but walking in it is unavoidable. If I plant corn it can take up half the garden space. I usually try to keep smaller plants in the garden like cucumbers on a trellis, bush beans, bok choy, tatsoi, Swiss chard, spinach in the cooler months in half the garden. 5 broccoli plants will occupy half the garden space from September to March. Corn will occupy it the rest of the time.

I keep the tomatoes in pots outside the garden because they just take up too much space. I also plant longer lived plants like the herbs and peppers in pots that are around the veggie garden. I grow ginger in a large pot and citrus trees in pots to keep them small.

I grow the gourds and squash vines at my community garden since it has more room to sprawl. I grow carrots, beets, asian greens, mandarin, calamondin, papaya, and a lot of weeds there.

My house has an acidic soil and fewer pests so it is better for tomatoes and plants that need to be watered or picked more often. The root crops like carrots, beets and daikon do better in more alkaline soils and with less nitrogen. Plants at the community garden need to be resistent to disease and pests; live on rain and deep watering a couple of times a week .

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Re: Advice On Building Raised Beds

Raised bed garden has a lot of benefits. Efficient weed control is the best advantage I had felt. Did you build the bed yet? If you don't want to build it with wood, there are other options like concrete or cinder blocks. I used wood as it easily available and easy to build.

Wish you good luck.

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