Raised Garden Beds on a Slope?

[Duchess of Stratosphear]

How have you made raised beds on a slope? I'm looking for cheap materials that don't necessarily have to look super nice or be permanent (if it breaks down in a few years, that's okay). I also want to be able to set it up in an afternoon. What have you had the most success with?

[Jack]

I made raised beds out of 2x8 lumber with 4x4 posts in the corners (the boards overlap the outside of the posts). Since it was on a slope, there's an extra board on the short sides and lower long side, with half of the short side boards buried (see MS Paint diagram).

People said in the past not to use pressure-treated wood near food crops, but in my opinion ACQ (as opposed to CCA) treated wood is safe. I used ACQ treated wood from Home Depot and good-quality screws (I think stainless steel, but it might have been hot-dipped galvanized) and my raised beds are still in great condition 5 years after installation.

[Duchess of Stratosphear]

Cool diagram! How long did that take you? I think that trying to bury something on my rocky soil would take forever, but those would certainly last a long time and look good!

[Jack]

Cool diagram! How long did that take you? I think that trying to bury something on my rocky soil would take forever, but those would certainly last a long time and look good!

The diagram only took me a couple of minutes! ; )

As for the construction itself, it was five years ago so I don't really remember -- probably a few hours. I do remember being slowed down by the fact that I was trying to set the screws using a cheap 14.4V cordless drill/driver, which caused me to have to pre-drill and maybe even wait for the battery to recharge partway through.

By the way, burying it doesn't take that long: you only have to dig out along the edges, not in the middle. Also, you could try just cutting the whole thing flush with slope of the ground... but I wouldn't trust it to stay put without at least digging in the 4x4 corner posts a few inches.

[PFHC]

You can make terraces out of hugelkulturs. They are free as long as you can collect enough logs, branches, and such. I built my first one a month ago on the side of a very steep hill. Took me about 4 hours and it is solid. The practice has been around a long time, tons of people in Maine use them. As for first hand experience, I'm not sure how things will grow, but the process all makes a ton of sense.

[lthenderson]

Back in the day, I made a bunch using used railroad ties but since they are soaked with creosote, I wouldn't recommend it anymore. These days I use rot resistant wood like cedar, redwood, osage orange, etc. On a slope, I typically don't even bother with the back side and just make it even to the slope. I essentially build a three sided box and sink the sides into the uphill side so that everything is level. Their are a couple advantages to this method. Less materials and labor and the raised bed tends to dry out more slowly than a completely raised bed since only part of it is above ground.

[Jack]

On a slope, I typically don't even bother with the back side and just make it even to the slope. I essentially build a three sided box and sink the sides into the uphill side so that everything is level. Their are a couple advantages to this method. Less materials and labor and the raised bed tends to dry out more slowly than a completely raised bed since only part of it is above ground.

That's a good idea. (Perhaps it's worth noting that in my raised bed design above, my beds were initially intended for a flat part of the yard and then moved to a slope, whereupon I added the lower board after the fact.)

[Duchess of Stratosphear]

I think three-sided is the way to go for me--less effort. I sort of need to get a couple of these set up in the next few months so I can plant my garlic in the fall.

I have some raised beds (on a flat space) where I've tried a sort of modified hugelkultur, but I'm not clear on how you are using the technique on a slope, PFHC. Do you use the wood and branches to sort of hold it all in place? It seems like you'd lose some soil on the downhill side otherwise.

[PFHC]

I have some raised beds (on a flat space) where I've tried a sort of modified hugelkultur, but I'm not clear on how you are using the technique on a slope, PFHC. Do you use the wood and branches to sort of hold it all in place? It seems like you'd lose some soil on the downhill side otherwise.

Ya. You just have to keep the downhill side from rolling away. I chocked up the bottom side with rocks to hold them during construction, then covered it all in dirt. It has since grown a weed/sod covering and seems to be holding rock steady.

Here's a drawing that shows how I built it and how I deal with the sides.

[bognish]

I made raised beds out of 2x8 pine joists from a deck that was being torn down. I used the 4x4 post in the inside corners to screw the sides on. The untreated wood has held up for 6 years of gardening and they were already pretty beat up when the deck came down. I added a few more boxes as the garden expanded with new wood 2x8's and they look fine after a few years. I am sure cedar would last longer, but I expect to get 10 years out of non-treated pine.

[Duchess of Stratosphear]

I have some raised beds (on a flat space) where I've tried a sort of modified hugelkultur, but I'm not clear on how you are using the technique on a slope, PFHC. Do you use the wood and branches to sort of hold it all in place? It seems like you'd lose some soil on the downhill side otherwise.

Ya. You just have to keep the downhill side from rolling away. I chocked up the bottom side with rocks to hold them during construction, then covered it all in dirt. It has since grown a weed/sod covering and seems to be holding rock steady.

Here's a drawing that shows how I built it and how I deal with the sides.

Sorry I didn't see this sooner. That's cool. How steep of a slope are you working with?

[PFHC]

I have some raised beds (on a flat space) where I've tried a sort of modified hugelkultur, but I'm not clear on how you are using the technique on a slope, PFHC. Do you use the wood and branches to sort of hold it all in place? It seems like you'd lose some soil on the downhill side otherwise.

Ya. You just have to keep the downhill side from rolling away. I chocked up the bottom side with rocks to hold them during construction, then covered it all in dirt. It has since grown a weed/sod covering and seems to be holding rock steady.

Here's a drawing that shows how I built it and how I deal with the sides.

Sorry I didn't see this sooner. That's cool. How steep of a slope are you working with?

Very steep. Right around 45 degrees. But, you could easily do it on something less steep.