I'm contemplating constructing a 32 sq. ft. raised bed garden (for vegetables). Several articles I've read have recommended stapling hardware cloth and lawnscaping fabric to the bottom before filling it.

Any thoughts on whether this is necessary or if it would just be adding complexity and cost? It seems more likely to me that the above-ground portion would be more vulnerable to attack from birds and animals than the bottom of the bed.

When I built my current 4x8 raised garden bed a few years ago (I plan to adding another 1 or 3 this year) I did the following:

I used cedar 4x4x8 for the posts, cut to 2 foot sections (I think that is the correct dimension).
I used cedar 1x6x8 for the sides - 2x boards tall for 12" depth of board.

I then placed the box where I wanted it, marked where the posts would be, and dug out a 4x8 hole in the yard (probably digging down and removing about a foot of material out of the area. So used a post digger for the posts, to about a 12-14" depth. The idea being to partially bury the edge of the bottom board a few inches under the soil line. Once the depth was achieved, I put pea gravel in the post holes and leveled the box with gravel.

Once I had the general area setup, I used a tiller inside the box to loosen the dirt about another 8 or so inches down so the earth wasn't as compacted (clayish soil around here). I stapled hardware cloth to the inside of the box and down into the ground along the edges and used the cloth staples for it - but I left the center of the box uncovered with cloth (so the plants can dig down as far as they want with their root systems).

I used the lawnscaping fabric more for the purpose of helping prevent soil from escaping from inside the box between the boards to outside.

I then filled the box up with a combination of the removed soil, compost, and potting soil and tilled it all together. I think I added some slow release fertilizer as well .

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birds and animals than the bottom of the bed.

When I built mine I put wire on the bottom to keep the moles from getting into the bed. It works because they dig around the bed but can't get into it. If I'm lucky I trap them within a few days.

I lined the inside of mine with a double layer of 6-mil black plastic as a weed barrier. Some holes were punched in the bottom every few feet so it didn't fill with water during rains. That's worked fairly well blocking out weeks and also stopping the raised bed from drying out too easily.

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Originally posted by bryan11:
I lined the inside of mine with a double layer of 6-mil black plastic as a weed barrier. Some holes were punched in the bottom every few feet so it didn't fill with water during rains. That's worked fairly well blocking out weeks and also stopping the raised bed from drying out too easily.

This is a question that I had.

My ground grows nothing but weeds and Ponderosa pines (those damn things are nothing but really big weeds...they will literally grow out of a rock). It is about 40% dead dirt and 60% river rock, so tilling it up and improving it is nearly impossible. Previously, I had four 4X8 raised beds that I had lined with landscaping fabric. It worked great for the first year, but after that, the weeds were able to get through it and it was impossible to keep them in check as the roots were clear under the bed and the cloth so they couldn't be pulled. Once the deer got through the cheapo fence that I put up and destroyed what I had, I abandoned that effort.

This year I've built a 40X40 area fenced off with 10ft 4X4s sunk into concrete and wrapped with welded wire (I dare the deer to try to get through this). Inside this area I plan to start with four 4X12 beds and was trying to think of a better way than just the fabric to line them. Black plastic came to mind, but I was concerned about the drainage and possible mold growth. I hadn't thought of punching a few holes in it, but hearing that you've had success with this I think I'll go that route.

I'm also going with standard 2X10s for the beds. They are a whole lot cheaper than redwood or cedar and I'll put them together with screws so they are easily replaceable should they begin to break down in a few years. If I line them with the plastic though, I'd guess I'll get a good ten years out of them before I need to replace anything.

I don't have anything under mine. I till it deep and don't want to fight barriers with my shovel. Do any of the articles tell you why they have recommended stapling hardware cloth and lawnscaping fabric to the bottom before filling it? I can't think of any reason to. I've seen plenty of people use sod/landscaping staples to hold down landscaping fabric on top to prevent weeds, that makes way more sense to me. You can actually accomplish almost the same thing with newspapers though, plus that's easier to remove and what doesn't come out easily can be tilled in next year.

Here's mine, a simple 8'x16' box built out of 6x6's. I built it in one afternoon with a buddy and a six pack.

It's constructed of 12 pieces of timber, about 30 pre cut 2' sections of rebar, and a dozen or so 10" spikes. No cuts needed. Just make a rectangle on the ground, then offset the next layer so that corners/joints are overlapping. When you drive the rebar through the corners and middle of the 16' sections it all gets tied together because of the overlapping.

I have been gardening all my life,and the one advice for you is a couple things.
Your grass and leaves are your friend when it comes to weeds in the garden,it is also plant food once the earth worms consume it.
The last thirty years I have been organic gardening,don't spend money on fertilizers or pesticides .
I do spend on organic potting mix for my tomato seeds and there is the concrete 100 foot rolls of wire I make my cages with.
Last year I had 200 plants,this year it will be
300 planted.
The micky mouse green house [I'm cheep]has well over three hundred plants up and most ready for planting now.
I sell at local market and last year I sold out ever open day.
I have crossed two varieties five years back and bread out the best traces yearly.
I do not till,that kill my earth worms,I use an 8 inch hole digger .

Thanks for the replies. This raised bed will be in a location I'm not too familiar with yet so after reading oldfireguy's post about the moles, I went and checked out the area again today. Sure enough, there were signs of moles fairly nearby.

Skins, mole activity was one of the reasons mentioned for the hardware cloth, so that made the decision to add the hardware cloth an easy one. I like the way you constructed your bed. If all goes well this season, instead of building and filling, I may try tilling the actual soil and building around it next year in another spot.

But for now, adding the hardware cloth means that I'll just fill the bed without tilling or digging beneath the bed. Based on what I've read, a foot of soil should be sufficient to support the root structure of everything I'm planning on planting at this time.

Gustofer, I also went with standard, untreated lumber for cost reasons. Around here, cedar costs about 50% higher and redwood even more than that.

45 Cal, are you composting your grass/leaf clippings and then applying it to your garden or using the clippings right out of the bag rather like mulch?

I've never had moles, maybe it's regional or because I'm in a subdivision, hopefully they cooperate with you.

My set up was not cheap. $600-700. It is built to last 20 years though.

I would advise against trying to fill a garden with soil. That can get quite pricey. I'd suggest using some of what you have. Dig out 8-12" and set aside. Lay your underlayment, derock what's you have piled aside. Then fill in your box(es), then add/amend to that. This will take some guess work. You will need to have some clue as to what the existing top soil is, ask neighbors or local nursery or garden center. I'd suggest mixing what you dug out with new good top soil, peet moss, and either chicken or horse manure. For the manure it's best if you can get older stuff not fresh. Also peat moss and manure are both highly acidic and all organics release acid as the decompose, so you will also need to add lime. If the soil is all clay it will take more peat moss and manure. If it's rich dark soil maybe just the manure. Lastly after your first season is over you will want to have the soil tested to see how good your guesswork was. Several colleges will test free or cheap, VA Tech I think is $12 or $20. Then in the fall/winter add whatever you are missing for the 2ND season.

Unless you have access to good soil above be the best way. Filling beds with bags of garden soil from Lowe's will cost a fortune.

I would not do anything just for now. Plan it to last a while. What if next year's plants require 18"?

The Beginners Guide to Gardening - The Survival Podcast
Fast forward ahead to the 13 minute mark to skip the intro stuff.

It in he says: "It depends."

-If you have the time and energy to deal with weeds, then there is a lot of benefit to not using landscape fabric.
-If, like most people, you don't have the time and energy to daily weed, then landscape fabric is probably a good idea.

BTW, FWIW, he also argues against raised beds.

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I would advise against trying to fill a garden with soil. That can get quite pricey.

I agree and won't be going the bagged soil route. I found a local material supply company which offers topsoil/compost in addition to their usual offerings. I'll just get them to fill my pickup bed with their front end loader and then back up to the raised bed and shovel it in.

I contacted the local extension office and got all the info for getting a soil test done through the state university system. Thanks for the ideas on amending the soil. Those should be helpful if I'm able to dig and till a more permanent area next year.

Davenator, thanks for that link. I'm looking forward to listening to that podcast. From the description, it looks like he knows what he's talking about.

i dont use plastic, i use the expensive weed barrier. lets water drain out. i don't have moles here. every few years i dig out the old soil and reapply a new layer on the bottom. mine is 4x8 and and about 1 foot tall. i do splurge on the organic soil.
Also do make sure you get untreated lumber. you don't want some treated lumber chemicals leaching into your soil.