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First raised bed for perennials

Dalton, GA(Zone 7a)

My first raised bed will be built soon so I'm starting to think about soil. Do I just get the raised bed soil at HD?

It is going to be in almost full sun and I will choose perennials that need the same care as in amount of moisture, fertilization, etc. The bed will be maybe 5 x 5 and 12" - 15" high.

The bottom will have only screening covering the ground (to keep out critters). The ground is rock hard except when there's a lot of rain.

So what do you think abt soil?

Dalton, GA(Zone 7a)

BTW, I've been googling this and almost all the articles assume you are doing vegetable gardening. I'm thinking that soil needs might be different for perennials.

Powder Springs, GA(Zone 7b)

Garden soil from HD is good if you don't have a ready made compost at hand. You are talking about 25+ cubic feet with the figures you cited which will take several bags to fill your raised bed. For example Miracle Gro garden soil comes in several sizes but if you get one of their biggest at 2 CF you would need 13 bags at around $8 a bag at Lowe's. You can also get some other materials such as peat moss and composted cow manure to throw in the mix. If it was a much bigger bed it would be cheaper to have a truckload delivered and dumped on a tarp so you could wheelbarrow or drag it to your raised bed site.

Soil is soil - veggies will grow in the same soil as perennials and vice versa. You will need to amend it from time to time though - fertilizer and other organic materials.

I don't know how bad your soil is now but have you thought of renting a roto-tiller and tilling up the area you want to use? Add in some organic material and till it in after you get the original area worked up. Or just add an inch or two of good garden soil or cow manure on top of a tilled up area and plant your perennials/seeds on top. Your top soil will grow over the years...

PS: If you are adding a screen to the bottom then you should also put a fence around the area since a lot of critters such as rabbits and deer will eat the plant tops instead of the roots (where moles, chipmunks, and voles tunnel).




Saint Louis, MO(Zone 6a)

If drainage is an issue, thinking ahead about putting an underlayer of gravel or crushed rock might be a good idea.

Dalton, GA(Zone 7a)

Wow, hcmcdole!!, I hadn't done the calculations yet!! That's a lot and I was planning on a 2nd bed - one sun and one shade. I guess I'll only be doing one.

I may have some compost later from my pile or my tumbler. Not having very good luck so far.

Fortunately, deer and rabbits are not a problem tho I've lost 3 or 4 plants to squirrels over the years.

Unfortunately, I'm not physically able to do rototilling or ammending the soil by shovel. That's why I decided to switch to raised beds (easier on my back also). Well, I'll have to give this some thought. Maybe put it off until my compost problems have been fixed.

One more question, all the articles talk about the soil sinking down (or something like that) and the need for adding soil each year. How is that accomplished when you have perennials planted?





Dalton, GA(Zone 7a)

Weerobin - a question. Put the gravel as the bottom layer of the bed filler? If so, how does that help? Won't the water still go down in the clay and be held there?

Powder Springs, GA(Zone 7b)

Yes, the soil will sink down (compact) over time but nothing to worry about. You can top dress as you see fit (add an extra inch or two of top soil around your plants). Even a small layer of compost will help every year or two - dig it in if you can but even just put on top will help. Mulch on top will also help to keep the soil temps even and aid against evaporation.

If you went with a layer of 6 inches instead of 12, then you would cut the number of CF of soil you need.

Can you hire a handyman to till for you? Or a friend/relative? A tiller can be quite jarring on the body when you try to till up hardpan clay but the more you work it the better it becomes. A tip to make working the soil easier is to soak the area you are interested in the day before working in it. If you get it too wet though clay becomes very heavy and you should give it a few days to be "friable". Too dry and it is like brick. It is definitely an anomaly - hard to get wet when it dries out like a brick and stays wet for a while when it is soaked. Hence the need to work in organic materials - leaves, wheat straw, peat moss, manure, top soil, sand, etc.

I would not put screen on the bottom but if you do use hardware cloth or chicken wire - not actual screen like on a door or window. These materials will all break down over many years - rust away.



Dalton, GA(Zone 7a)

I was thinking more of the compost breaking down and losing volume that way. Thought we might be talking 3 - 4 inches. (Guess it depends on how much compost you put in the planting mix.) Assuming the plants sink down with the soil, I was worried about soil refill covering the crowns and causing crown rot.

It would be hard to till now as there are trees, shrubs and in ground beds. I do hire my neighbors to help me some when there's a month I can afford it. Over time, parts of the area have been planted. But I want to dig up all the perennials and put them in the raised beds. I think they will do much better and my back will be saved..

I need the beds to be as high as possible for my back but I am limited by the amount of wood I have. Some of them will only be 8 to 10 inches high. (I'm using reclaimed wood from an old play structure the kids had when they were little. Now I can have some fun with it!)

I may have learned recently why the soil is so hard in my backyard. (I love hearing stories about the previous owner from my neighbor.) It seems that the prev owner was extremely, shall we say, "thrifty" and loved a good deal. So when a business closed and put a really good price on their bags of lime, prev owner bought 200 lbs. and spread it all over the back yard. The story goes that the next spring he couldn't even get a shovel in the ground to plant his veggie garden.

Last thing, what I'm calling screening, actually is chicken wire I'm told. I had just never seen it with such small holes. However, if I really don't need it, I could possibly use it to build a holding area for the mulch from the tumbler. Maybe a better use for it?i

Powder Springs, GA(Zone 7b)

You definitely do not want to cover the crowns of your plants as this could kill them (some plants might be able to push up from being covered but better safe than sorry). Often plants’ surface roots will be exposed as the surrounding soil is washed away or compacted. It can be death either way – planted too deep or too high.

Yep, tilling around trees and shrubs could harm them. A raised bed over tree/shrub surface roots can be harmful as well. I would use pots for these areas instead unless you can move the raised bed far enough away from the trunk of a tree/shrub.

Better soil will definitely help out the plants and maybe your back to a lesser degree. Extra work will still be needed to get it going and you will need some maintenance after that.

You might need to just get a bench of some kind and put some hefty pots on it to get the plants at a height you and your back would be comfortable with. A lot of plants don't need a lot of depth - just good soil, room to grow, and a good location (sun requirements). You may have to water more often since pots tend to dry out quicker than the earth.

200 pounds of lime over how much area doesn't sound like a lot and should not make the ground hard. You could try gypsum that has similar traits as lime (sweeten the soil) and also help to break up clay. I don't know how much is needed though and I haven't seen that it helps that much but check it out.

Lime is often good to add to a compost pile especially to neutralize the odors of green material breaking down.

Have you got voles, moles, and chipmunks in your yard? I've never used cages underground to protect bulbs and the like but there must be folks who have had problems with these critters and therefore a market for protecting roots and bulbs.

Here is a photo of a homemade bench at one of the nurseries I visit. Looks like cinder block legs and wooden pallets to hold their perennials up for the buying public.

Thumbnail by hcmcdole
Dalton, GA(Zone 7a)

Well, it sounds like I'm ok as far as being able to replace lost soil volume without harming the crowns. That was my main worry. So I really want to try one raised bed and see how it goes. Maybe reduce the size to 4 X 4 and 10 inches high to reduce the cost of filling the beds. And I will be able to use some of my compost after all.

Oh, and all beds on that side of the yard will be away from the trees.

Thanks SO much! Now I just have to decide exactly where to put this first one.

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