Raised Beds

[bev]

I am planning to make some raised beds and want to make them about 2 feet high. However I do not want to use precious soil to fill that space completely.

My thoughts are to put stones in the bottom of the beds to a height of one foot, filling in around them with a sand/clay mix (that I happen to have in a pile in the yard). I would top the stones with this and level it out leaving about one foot for good garden soil.

Does this sound workable?

One of my concerns is the stones might create a haven for garter snakes and I don't want them near our house. Should I put a fine mesh hardware cloth or perhaps plastic window screen (stapled firmly) on the bottom of the box?

Any other issues that I should consider before making the beds?

[mnjrutherford]

I'm not an expert. I have heard that a layer of rocks covered with good soil is good for plants. I think I read that on this forum around the time I first joined.

[grunt]

Bev: I would just take 6" of soil from what is going to be your pathways, and pile it on where you want your beds. That gives you a net bed height of 1' relative to your pathways, and is is all good garden soil. Rocks tend to interfere with root veggies. Then if you decide you no longer want the beds there,you just flatten everything out. I would never intentionally put rocks in my garden soil = I spend far too much time trying to get them out.

[honeydew]

Bev, I'm no expert on raised beds, but I think it may depend on what you plan on growing in it.

Your different vegetables will have different root systems, some of which will extend down significantly below the soil surface.

Rocks may affect this? I seem to think you will want to give them more depth...

If you can get a copy of Steve Solomon's "Gardening When it Counts: Growing Food in Hard Times" (from the library perhaps - but you may find you want your own copy) it has some great information on root systems and spacing issues of particular vegetables.

What is your soil like? This book also discusses improving your soil, and what to add to make it better, which of course, will make more volume of soil at the same time.

I would be tempted to use a trench compost technique to build up your level and put your soil on top. I would go back in the fall or next spring and deeply mix it with the soil at the surface.

Marie

[bunkie]

Feb 13, 2011 11:53:13 GMT -5 mnjrutherford said:

I'm not an expert. I have heard that a layer of rocks covered with good soil is good for plants. I think I read that on this forum around the time I first joined.

i'm no expert either, but i have heard that rocks will impart knowledge to nearby plants.

[bev]

Good points but I am not working with an existing garden.

I am making bottomless boxes (4'x12') to put in an area that is currently, shall we say, marginal lawn. I want them 2' high because I have knee and back issues that have prevented me from gardening for a few years. I am planning to lay cardboard under the boxes to kill the existing grass.

I read somewhere recently where someone asked how much soil was needed to put a raised bed over concrete and the reply was "3 inches deeper than how long you want your carrots to grow".

We have only 6-8" of topsoil on farmland around here; below that is what I have heard referred to as "blue clay". Our older gardens have more soil but not more than 10 - 12 inches and then things get pretty hard.

The soil we have is not great so I am planning to amend it with some purchased materials and homegrown composted manure. The "purchased" part is why I do not want to entirely fill the boxes with soil but would rather have a "filler" layer. Rocks are readily available and my hubby has a bobcat. I also have this huge pile of a sand/clay mix that needs a home. It would be between the "good soil" and the stones.

Our potatoes and corn will be grown in the old gardens. I am hoping to grow most everything else in raised beds.

I've still got some time to ponder it all - there's a lot of snow out there to melt yet.

[honeydew]

I tried making a raised bed two years ago by covering with cardboard to kill the grass. It wasn't terribly effective in my experiences. The grass just found a way through, and around the edges.

After three years of creating gardens from grass or otherwise vegetated spaces, here's what I do now:

Need a bed now: Do you have a rototiller? I would till up the grass as soon as you can in the spring and wait 2-3 weeks, till again. Then make your raised bed. Or if you only have time to till once, remove the clumps of sod and broken bits of grass shoots best you can, cover with cardboard (no color inks on it) and make raised bed. Be diligent about removing, including the roots, any grass that shows up immediately.

Planning ahead: Use a ground cover that will deprive grass of all light and water. I used one of my 100'x12' pieces ground cover and secured it with rocks from the rock pile to kill the grass. I put it on last spring, and left it. I checked in the fall, the grass was dead. I did this because it runs right overtop of our electrical services from the road, so I didn't want to risk taking the deep tiller and disc over it.

Another thing: I would get rid of the grass around your beds too. Either place them side by side, with a grassless border of at least the width of your rototiller if you have one, and no grass in your pathways, or, plan to routinely edge the grass so that it doesn't start growing underneath and up in your beds.

Can you rototill the 'garden area' where the raised beds will go first? You could then get your husband to scrape off the good topsoil with his bobcat, and reuse it in your soil mix. Then you are less likely to have a grass problem. But now that I think about it, you could skip the whole rototilling part, and just get your husband to scrape off the sod, and you could use it once the grass is dead. Measure and mix with your amendments in a wheelbarrow and fill your boxes.

I think a few rocks in there to take up space would be fine, but not a dense layer of them.

[castanea]

Feb 13, 2011 11:39:40 GMT -5 bev said:

I am planning to make some raised beds and want to make them about 2 feet high. However I do not want to use precious soil to fill that space completely.

My thoughts are to put stones in the bottom of the beds to a height of one foot, filling in around them with a sand/clay mix (that I happen to have in a pile in the yard). I would top the stones with this and level it out leaving about one foot for good garden soil.

Does this sound workable?

One of my concerns is the stones might create a haven for garter snakes and I don't want them near our house. Should I put a fine mesh hardware cloth or perhaps plastic window screen (stapled firmly) on the bottom of the box?

Any other issues that I should consider before making the beds?

Something you should consider - snakes will eat the critters that eat your plants.

[bev]

I wouldn't depend on just cardboard to kill grass but I am thinking that underneath the beds it won't have much chance with no light source to aim for. Planned to extend the cardboard out into the pathways which I will cover with some kind of barrier and a layer of gravel. Grass and Canada Thistle have been my biggest garden problems and if either of them finds a way to poke up into my pathways I have ways of dealing with them.

There is an old concrete pad in our yard and I plan to spread soil and whatever I amend it with on there, cover it with an opaque tarp and hopefully kill most weeds that grow or germinate. Then we will mix it and put it in the beds. I should have at least a month window to prepare the soil and will hopefully start out mostly weed-free.


"Something you should consider - snakes will eat the critters that eat your plants."

I know but we have two aquaintances that have had to abandon their homes after being invaded by snakes. If they ever get in you can't get rid of them. So we try to keep a snake free zone around the house. We have on several occasions had tiny toads inhabit our garden. I like them and I expect they take care of some pests while they are hiding out from the snakes.

[coppice]

Bev, while I have been only breifly gardening, oh like the past fourty years. Based on my direct experience using a light blocking layer does effectively kill grass and hay feild if applied to sod first and is a few inches bigger than the applied bottomless box, with NO GAPS.

I do use mobility aides to get around these days and find a raised bed much taller than twelve inches tall both exponentially more expencive because two-by lumber is inadaquate to the volume of soil being contained. And a taller bed doesn't do for me what wider aisle space permitting a roller or walker into the garden does. Your beds should be no wider than four feet and should be aproachable from both sides. Six feet of end space between ends of beds is another minumum.

I've cut down hoes/rakes to adjust to my changed reach in beds. Cut your to suit you as you try them.

You can fill bottom of beds with brush or any other unpainted or untreated jumber. It will rot away into a big sponge; see Hugelkulture.

[bev]

coppice I really like the idea of using wood as a filler. We have plenty of deadfall wood in poplar bushes in our pastures. It would slowly decompose and my beds would shrink but I could top them up with compost each year. Then, if we at some point decide to remove the raised beds we will just have "soil" that we could spread around instead of a bunch of rocks to relocate when we are too old to lift them. We have alkaline soil here and I expect that the wood would help balance that (someone correct me if I am wrong).

[bertiefox]

Coppice's idea is what is called a 'German mound' isn't it? You can use it to dispose of a pile of old clippings, wood and other bulky organic material, half burying it and then covering with a layer of compost and soil. In theory the wood and other organic material retains moisture and gradually rots down releasing nutrients into the soil. I find that beds that are too shallow never retain enough moisture and aren't much use for many root crops. I'd say one foot of growing medium is an absolute minimum.

[coppice]

Feb 13, 2011 20:44:07 GMT -5 bev said:

We have alkaline soil here and I expect that the wood would help balance that (someone correct me if I am wrong).

Yes brush does break down over time and when it should come time to dismantle beds the remains become, well simply dirt. I expect that brush and leaf mulch will not much change your soil PH.

If you really need to change PH your going to end up with additional sulphur (acid) or Lime (alkaline)

[qunuk]

Compost, 100% cotton/wool, bones, etc., and non-aged manure will do if you can get it (far enough down it won't burn the veggies) will heat up the soil. We have a compost toilet (nuf said)

[steev]

If you want to kill your sod-pile by covering it with plastic, it's better, if you have good sun, to use clear plastic over a wetted pile. It's called solarizing and actually gets hotter to kill the growing grass/weeds.

A possible side benefit to basing your bed on clean wood might be inky-cap mushrooms, Coprinus comatus, if you can find some to seed with; they like buried wood as a medium.