Ask a Question forum: Reclaiming a garden (raised bed question)

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Long Island, NY (Zone 7b)
Scott_R
Mar 26, 2017 4:56 PM CST
For years I had a vegetable garden in a space some distance from the house. What with one thing and another, I stopped planting. Now more time than I'd like to consider has elapsed since I used the space, and I'm looking to start up again (the last couple of years I've used a small space near the house, but it's a bit crowded and sun is limited).

So, I'm looking to reclaim the space, with some complications. By far the biggest two are:
-- it's become overgrown. Not filled with brambles and brush, but adjacent lawn has grown to cover the area; the grass has been kept mown.
-- I leave near the bay on Long Island, NY, and coastal flooding has become more of an issue than it used to be. The place I've been growing the last couple of years is above all but major (hurricane) flooding but the old garden certainly is not. That's an issue for maybe a few times a year, but it's certainly an issue. I don't know what the salt content of the existing soil is.

So my basic solution is raised beds. But not just the typical 6-8 inch frame filled with dirt, but something higher. I'm not anticipating flooding, but I can't dismiss the possibility.

My two considerations:
1) do I rent a tiller? Or put plastic mulch over the grass and put the beds on top? Or use a spade to skim off the grass and build on that, with or without the plastic? (I figured that if I'm building higher than usual, room for the veggie's roots are less of an issue.)

2) what the heck do I build this out of? From what I've read cinder blocks are not advisable because of fly ash content. Then I considered retaining wall blocks, but realized that they're not stone for formed concrete, and may have the same issues. Untreated timber likely won't last long.

The space I was originally going to do was 10x12. But because of the scale of the raise, I'm going to drop that to 8x10 (why that size will be clearer below).

Home Depot has 4"x4" x 8' cedar; that would mean 9 pieces to get two levels, rather lower than I'd wanted (and just 3.625 actual). That's about $171 of lumber, before tax. But I was considering the complication of access to the plants... unless I wanted to (and could) climb up onto the raised bed, two 4x10 spaces would give me better accessibility, with a walk through in between. That would mean 14 pieces of cedar, and I'm up to $266, pretax, and lower height than I'd have wanted.

Then I thought, if I used concrete blocks, they're 16 in. x 8 in. x 6 in., so for the double planter I'd need 44 per level, 88 altogether to get to a full foot of height. At $1.50 each that's $132.

If I lined the insides with heavy plastic, there won't be an ash leeching issue (I'd only have to worry about BPA and phthalates and the like. sigh).

That would bring me to a full foot in height. I'd already planned to have 4 yards of topsoil delivered (for other things around the property as well, not just for this snowballing project) so that would bring me within 2" of the top... and I have quite a bit of garden soil (from the current beds) to supplement.

OK, long post, and I could go on... but any thoughts so far?
For years I had a vegetable garden in a space some distance from the house. What with one thing and another, I stopped planting. Now more time than I'd like to consider has elapsed since I used the space, and I'm looking to start up again (the last couple of years I've used a small space near the house, but it's a bit crowded and sun is limited).

So, I'm looking to reclaim the space, with some complications. By far the biggest two are:
-- it's become overgrown. Not filled with brambles and brush, but adjacent lawn has grown to cover the area; the grass has been kept mown.
-- I leave near the bay on Long Island, NY, and coastal flooding has become more of an issue than it used to be. The place I've been growing the last couple of years is above all but major (hurricane) flooding but the old garden certainly is not. That's an issue for maybe a few times a year, but it's certainly an issue. I don't know what the salt content of the existing soil is.

So my basic solution is raised beds. But not just the typical 6 inch frame filled with dirt, but something higher. I'm not anticipating flooding, but I can't dismiss the possibility.

My two considerations:
1) do I rent a tiller? Or put plastic mulch over the grass and put the beds on top? Or use a spade to skim off the grass and build on that, with or without the plastic? (I figured that if I'm building higher than usual, room for the veggie's roots are less of an issue.)

2) what the heck do I build this out of? From what I've read cinder blocks are not advisable because of fly ash content. Then I considered retaining wall blocks, but realized that they're not stone but formed concrete and may have the same issues. Untreated timber likely won't last long.

The space I was originally going to do was 10x12. But because of the scale of the raise, I'm going to drop that to 8x10 (why that size will be clearer below).

Home Depot has 4"x4" x 8' cedar; that would mean 9 pieces to get two levels, rather lower than I'd wanted (and just 3.625 actual). That's about $171 of lumber, before tax. But I was considering the complication of access to the plants... unless I wanted to (and could) climb up onto the raised bed, two 4x10 spaces would give me better accessibility, with a walk through in between. That would mean 14 pieces of cedar, and I'm up to $266, pretax, and lower height than I'd have wanted.

Then I thought, if I used concrete blocks, they're 16 in. x 8 in. x 6 in., so for the double planter I'd need 44 per level, 88 altogether to get to a full foot of height. At $1.50 each that's $132.

If I lined the insides with heavy plastic, there won't be an ash leeching issue (I'd only have to worry about BPA and phthalates and the like. sigh).

That would bring me to a full foot in height. I'd already planned to have 4 yards of topsoil delivered (for other things around the property as well, not just for this snowballing project) so that would bring me within 2" of the top... and I have quite a bit of garden soil (from the current beds) to supplement.

OK, long post, and I could go on... but any thoughts so far?

thanks.
Name: Barbalee
Amarillo, TX (Zone 6b)
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Barbalee
Mar 26, 2017 5:20 PM CST
I have no thoughts, Scott, but wanted to give you a welcome! Welcome! I'm sure folks with thoughts will be along soon!
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Name: Heath
sevierville TN (Zone 7a)
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plantcollector
Mar 26, 2017 6:52 PM CST
My thoughts would be to first scrape off all of the top growth and amend the existing soil. Then if you want it deeper I would use 2 by 6 or 2 by 8 pine. Yes it will rot but you can get 2 to 5 years or more and they are not going to rot at the same time so you can replace the ones that rot and keep the good ones.
Name: Meri Taylor
SD (Zone 4b)
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mnmat
Mar 27, 2017 1:16 AM CST
Smother your grass by laying layers of cardboard down inside the raised beds. I always use landscape fabric tacked around the inside edges just covering the seam where the frame sits on the ground. It helps keep the soil contained.

I made my raised beds using composite lumber like Trex. It lasts forever and doesn't ever rot. Do not use composite 4x4's for any corner posts. The cut end absorbs water, swells and blooms like a flower but not as pretty. I've moved 3 times and drug the frames with me from house to house. The last move I even brought the dirt. Since I made them many years ago I don't know what they would cost now days. But since you only have to invest once it might still be worth it. Do you know any contractors? Maybe you can find odds and ends.

One of my other raised beds is an old waterbed frame. I have to replace the end board this spring. Shrug! Crying
Meri
Long Island, NY (Zone 7b)
Scott_R
Mar 28, 2017 10:45 AM CST
Thanks for the replies. I'll admit, I'd automatically dismissed pine, but this got me thinking, "why not?" For various reasons, long-term won't be that much of an issue so I don't need this lasting for decades. Maybe I can use some nontoxic oil to slow rotting.
Name: greene
Savannah, GA (Sunset 28) (Zone 8b)
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greene
Mar 28, 2017 11:04 AM CST
Sounds like you are doing quite a bit of thinking. If you lay down a good layer of cardboard you should be able to start building the boxes right away.

For raised beds I had always used 2x lumber but I have been using cedar boards lately. To insure that the cedar lasts a long time I build the box with the lowest "board" made from plastic edging. Here is a photo to show what I mean; it is an up-side-down. There is another narrower board behind (not pictured) to join the two together and prevent soil from spilling out.
Thumb of 2017-03-28/greene/f73efc

Here is a picture showing both ways - with the plastic and with only the cedar as the bottom board.
Thumb of 2017-03-28/greene/847bee

Whenever I go to Home Depot I always stop by the mark-down area and buy the cedar when it is marked down 75%; after a few months I have enough to build a bed. For the plastic edging I try to pick that up either at end of season sales or at yard sales. Sometimes people even throw away the plastic edging and I pick it up for free as roadside trash.



Sunset Zone 28, AHS Heat Zone 9, USDA zone 8b~"Leaf of Faith"
Name: Rick Moses
Derwood, MD (Zone 7b)
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RickM
Mar 28, 2017 11:25 AM CST
Welcome! Scott !

Concrete block sounds like an easy way, but it will dry out faster. The upper courses are also prone to slipping, usually at the wrong time.

Whether you use wood or concrete, you'll probably want to line the side walls. That will prevent any roots from working their way into and through the joints. Also, depending on what kind of material you actually fill the beds with, it will settle and decompose over the first few years. You'll most likely need to top it up at that point.

If you go with wood, you will need to support the outside of the walls to prevent them from bowing out, unless you use shorter, 3-4 feet, sections of wood.

Here are links to a few safe products that you can use on the wood as a sealer/preservative.
https://raisedbeds.com/eco-woo...
http://www.greenbuildingsupply...
http://www.greenbuildingsupply...

Going with 2 parallel beds is the way to go. That climbing up and down gets old really fast. If you do put in the path, put down some landscape fabric and then a 2-3 inch layer of mulch. It won't need mowing, will stay clean and dry and any weeds that try to come up will be easily removed.

Lastly,, consider putting a small bench or two nearby. That will give you something to set plant material on when you're planting/harvesting. Heck, you can even use it to take a break.

Oh, and don't forget water! You could bury a hose from the house and hook up a hose stand.

Keep us posted on your progress.
Long Island, NY (Zone 7b)
Scott_R
Mar 31, 2017 5:12 PM CST
Thanks for the help. I've been reading that treated wood may be OK for use around vegetables. I can't post a link (new member), but search for "natural handyman Using Pressure Treated Wood For Raised Gardens" without the quotes

But it's academic, as I came across that AFTER I bought my wood. :)

So... I now have twelve 10' pieces of untreated pine (2x8), and twelve 5' pieces of same (10 footers cut in half). That'll give me two 5x10 boxes, three levels high (since 2x8's are only 7.25 actual, that's 21.75 inch walls).

I also bought what's supposed to be a vegetable-safe wood treatment. Again, I can't post a link, so search for "tall earth Eco-Safe Wood Treatment"

So... I plan to line the inside of the boxes with plastic. Is there any sort that's more appropriate for a garden? I.e., won't be leaching BPA or phthalates. I was thinking I should have the plastic go UNDER the walls, isolating them from the soil, as a sort of kludge-job replacement for using the plastic boards at the bottom. Should the plastic also wrap around the top, to help reduce rain from getting trapped between the plastic and the boards?

For the walls, I'm connecting them by vertical 2x4s at each corner; I'll also attach the 2x4s in the middle of each 5' section. Not sure if I need go with one or two evenly spaced along the 10', but either way I thought I'd hammer in some rebar just on the outside, right in the middle, to give added support from bowing out. Would that be enough? My concern was that enough pressure would also push the rebar (outwards, not upwards), since it's so thin it might not give enough lateral support.

Happily, I have a spigot <10' from where the raised beds will be.
Long Island, NY (Zone 7b)
Scott_R
Mar 31, 2017 5:31 PM CST
Answering one of my own questions: I think the 6mil black plastic (polyethylene) sheet rolls should be all right.
[Last edited by Scott_R - Apr 1, 2017 11:34 AM (+)]
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