I'm no expert on raised garden beds but I think you should place the cardboard on the ground and cover it up with compost or what ever you were going to make your bed out of. My daughter did this with her raised bed garden and it worked extremely well.

Hazel,

It is 90 degrees in late October because this is Oklahoma. Our weather doesn't follow the rules and merely does as it pleases. The nice thing about our fluctuating autumn weather is that it can be 90 degrees one day, 70 degrees the next and headed for highs in the 50s before you know it. I'm tired of the heat, but I still would rather have a 90-degree day (or 2 or 10 of them) in October than a day with a high of 50 degrees. Winter will be here soon enough and we'll miss our 90-degree days.

Bed-building and soil-building are the foundation of gardening. Everything you do in your garden begins with the soil. You cannot grow a lovely, healthy, productive garden in bad soil. So, I apologize in advance on how long this response is going to be, because when I start talking about building beds and enriching soil, I go on and on forever. It is a complex topic, and a very important one.

The bad thing about rototillers is that the chop up the bermuda grass stolons into little pieces. Those little pieces don't rot or decay when left in the ground. Instead, each of them sprouts and grows you a whole new crop of bermuda grass. Oh joy, oh joy? Think I am exaggerating? Nope. If you leave even a 1/4" long piece of bermuda stolon every 3' or so, it will regrow and can completely recover the rototilled area next spring after a month or so. Ask me how I know this? Some of the lessons we learn best as gardeners (and never, ever, ever forget) are the ones that were the most painful.....like the lesson that rototilling bermuda grass is a great way to create a million new bermuda grass plants.

So, your first task is to carefully and painstakingly rake through that soil and remove every piece of bermuda grass stolon that you see. I wouldn't even compost them. I'd put them in the trash and have them hauled away.

We are in our 16th year here. We used a rototiller to break up the ground for our garden. I have fought bermuda grass like crazy for 16 years now and have finally, after 16 years, mostly eradicated it from the fenced-in garden area. However, I know that if I turn my back and ignore the bermuda grass for a month, it will creep and crawl under the fences and restablish itself and I'll be starting over from square one. So, my advice is that you get out every bit you can now, and then every time you see any sign of a sprig of bermuda grass springing up in or near your garden, immediately drop what you are doing and dig it out. Don't pull it out because pulling causes the above-ground portion to break off in your hands, leaving roots and stolons underground to regrow.

For the new beds, I would put down as many layers of cardboard as I could on the ground at the base of the bed. Wet them down. Wet cardboard will attract earthworms and they will eventually chew up and decompose the cardboard. This is a good thing. As they eat the tunnel through the soil, they break up the ground and aerate it and leave earthworm castings (aka worm poop) behind to enrich the soil. Then, pile your lovely brown soil on top of the cardboard. Hopefully by spring, you'll have compost to add to the soil. And, you don't have to wait until spring.....

One of the best soil conditioners in the world is autumn leaves. Many of the nutrients your garden plants need are found in those autumn leaves. As the leaves decompose, they enrich your soil and feed your plants. We drive over our leaves, right there on the lawn, with the lawnmower with the grasscatcher attached. The grasscatcher collects all the chopped up leaves and grass/weed clippings. We then dump all of that right on top of the beds in the fall. We wet it down to keep it from blowing away. In a good year, I like to put 6 to 8 inches of chopped up/shredded autumn leaves and grass clippings on top of each bed. They cover the soil, which keeps it from eroding. They cover the soil, which helps prevent weed seeds from sprouting. (More about weed seeds in a second.) That might not sound important right now, but soil left bare all winter can have winter weeds 3' tall or taller before planting time rolls around. When you let winter weeds get that big, they are hard to pull out, so you have to dig them out, which exposes the bare soil to sunlight as you dig and the sunlight causes even more dormant weed seeds to sprout. It is easier to mulch the top of your new beds and prevent the weeds from sprouting than to have to remove them later. Usually (it depends on how dry or wet the winter is), when I pile on a mixture of chopped-up autumn leaves and grass clippings in October or November, I have compost by spring. If yours doesn't decompose that quickly, you can rake it back off your beds in spring, plant your seeds or your transplants, and then after the plants are a couple of inches tall and all the seeds have sprouted, pull that mulch back onto the beds to prevent weed seeds from sprouting.

Weed seeds of many kinds can survive dormant in the soil, not just for years, but for decades, and because most of them are very tiny, there can be thousands of them in even a small area. It only takes a second (for some weed seeds, less than a second) of exposure to sunlight for weed seeds to get enough light to initiate sprouting. So, when you rototill, you are waking up millions of weed seeds and telling them to go ahead and sprout. Some will sprout soon after you rototilled, others wait until the moisture and temperature levels hit a certain point in spring. That's one way that weeds infiltrate beautiful, fresh, new garden plots---they have been lying there in the soil waiting for years for someone to come set them free. It sucks, doesn't it?

Using cardboard as a bottom layer for a bed, or to cover a larger, newly rototilled area is a wonderful idea. I hoard cardboard in our garage like a miser hoards and counts coins (I know my cardboard collection drives my husband nuts) because it has so many wonderful uses in the garden. If you wet it down with the garden hose when you first lay it on the ground, that will hold it in place until you can pile stuff on top of it. You can pile anything you like on top of the cardboard: bark mulch (the finer and smaller the pieces in this case, the better), compost, partially-finished compost, small twigs, chopped/shredded autumn leaves, grass clippings, spoiled mulch or hay (if you don't understand how these can harbor herbicide residues let me know, and I'll tell you), stable bedding from chicken coops, barns, etc. (same issue with herbicide residue is a possibility), etc.

If you don't have lots of lawn to mow for clippings or lots of autumn leaves to gather, sometimes if you ask your neighbors if you can have their grass clippings/raked leaves (if they bag them and put them out on the curb instead of composting them), they are happy to give them to you. Otherwise, some organic gardeners have been known to drive around neighborhoods at night gathering bags of leaves/grass clippings that folks put out on the curb. Some cities chip up and shred the leaves and twigs and let you come pick up that 'compost' for your own use. Some cities do the same thing with live Christmas trees after the holiday season is over. There's lots of ways to find free mulch or free compost pile materials, and those materials will help improve the soil you have.

Now, it is great you found lovely brown soil, but you can get ahead of the game by doing the simple jar test I will link below that will help you understand its composition and texture.

Are you pretty new to gardening? If so, it might help to know a little more about soil. Soil is not dead and inert. (I think of plain old dirt, low in organic matter as dead soil that is low in living organisms.) Soil is alive. It is teeming with microbes of all kinds that help plants in many ways and assist with breaking down minerals and nutrients in the soil so plant roots can absorb them. Ideal garden soil that is healthy and balanced nutritionally is composed of many different things. The "dirt" itself is just minerals in different amounts. Ideally, your minerals would be roughly 65-75% calcium, 12-20% magnesium, 3-7.5% potassium, 4-5% oxygen (I like more, but even freshly tilled, fluffed-up soil packs down quickly so that 4-5% oxygen is typical), 2.5-5.0% humus, and 0.5-3.0% sodium. The other nutrients are present in parts per million. I don't specifically worry much about the nutrients that are available in parts per million. As long as I am adding plentiful compost to the beds every year, they pretty much take care of themselves. The soil microbes can be present in healthy, balanced soil in amounts as high as 50 billion per teaspoon of soil. In soil that has been depleted of organic matter and is very low in nutrients, you won't have many microorganisms. One way to encourage healthy soil microbe levels is to spread dry molasses (or, if you cannot find that, even plain table sugar) on the ground and work it into the soil to feed the microbes.

Ask yourself how Mother Nature builds soil and seek to emulate it. My favorite example of this is to take somewhat on a walk through a forested area. Look at the forest floor. Do you see "dirt"? Usually not. We know there is soil down there, but it is hidden beneath layers of decaying plant matter. If you could cut a cross section into the ground of a forest floor and examine it, you'd find stuff present in layers. The top few inches is organic matter that is lying there covering the ground and just beginning to decompose: leaves, dead annual or perennial plant growth that has died back in fall or winter, twigs, bark that has sloughed off trees, dead insects, even small dead animals or birds, and manure from various animals, insects and birds. Beneath that upper few inches is older material, mostly a mixture of partially decomposed organic matter and minerals (soil). Underneath that is the subsoil, which sometimes is clay in OK, but certainly not always. Mixed in with those upper layers you will find ground-dwelling macroorganisms like earthworms and other decomposers. About the top 6-8" or your cross-section of forest floor is rich and humusy and it has the best oxygen levels. Once you get deeper, the soil is not as well-aerated. In our woodland near our house, when I dig down through all those layers, I hit the dense red clay about 10" below the surface of the soil. That top 10 inches of layers of soil and organic matter, in conjunction with the red subsoil beneath, have nourished our woodland for at least 80 years (based on the memories of the older residents of this area, some of who tell me that there used to be "no trees" in our neighborhood so they had to go to the Red River nearby to gather and haul home firewood when they were very young). Grassland also builds soil, but more slowly because it mostly has only decomposing grasses and forbs to feed it except for scattered trees here and there in the grassland.

When we started our garden, my main goal was to take the dense red clay that was compacted hard like concrete and covered maybe 80% of the garden and the lean sandy/silty soil that covered the remaining 20% of the area, and to turn them into dark brown, humusy, rich soil that resembled the forest floor. That still is my goal. My raised beds do not yet have soil that resembles the forest floor as much as I would like, but I do think that it gets closer every year. As the soil has improved, the growth and production of the plants I grow has improved as well.

Don't make yourself crazy overthinking bed-building and soil improvment. Just set a goal to have soil that is humusy, rich and that smells like the forest floor in springtime. If you achieve that, your plants will grow like mad. It isn't hard. Pile stuff on top of the ground and it will eventually decay.

When I make new beds in the fall, I try to pile up stuff on top of the cardboard a couple of feet deep. I don't mean that I do that all in one day. I put 5 to 8" of stuff on top and then every time I do any yard or garden clean-up work, I add more.

Or, you can Google and read about lasagna gardening. As its name implies, it is a more structured form of bed building where you use various ingredients (purchased as well as those obtained from the yard) layered into a bed to build new beds. If you do lasagna gardening with all-purchased ingredients, it can be pricey. In our early years here, and I believe that was before Pat Lanza coined the phrase 'lasagna gardening' and wrote her books, I mixed together local materials gather on-site with purchased, bagged materials, to make our early raised beds. While the use of the term 'lasagna gardening' is new, people have built gardens by layering organic matter on the soil for a long, long time. Ruth Stout did it with mostly salt marsh hay.

Also, if you are new to composting, the most important thing to know is that all those materials you pile up with break down to 1-3% of their original volume. So, if you pile up organic matter 4 feet tall on your whole compost pile in October, you'll have a few inches of compost at planting time. Many people who are new to composting start out with very short piles and are stunned in spring to find they have a quarter-inch to a half-inch of compost in their pile at planting time. I always aim to make my piles no shorter than 4-5' tall because that is what it takes in order for me to have all the compost I need in spring.

The other important thing about soil improvement is that it never ends. I pile 4-8" (not all at once---an inch to three or four in spring after plants are up and growing and then more added over time) of mulch on top of all my raised beds each spring and summer. By fall, that stuff has decomposed down from, let's say 8", to an inch or less. By continually mulching with organic matter that will break down, you are continually feeding and enriching your soil from the top down----the same way Mother Nature feeds and enriches the forest floor by dropping leaves and other plant parts onto the forest floor year-round.

For too long in this country, too many people in farming, ranching and gardening have fought Mother Nature and tried to work around her and leave her out of the equation as much as possible. It simply doesn't work. Soil has to be replenished with organic matter of all kinds, not just with chemical compounds. If you always try to garden with Mother Nature, your soil will be incredibly beautiful.

Now, bermuda grass is evil. It has ruined gardening, both edible and ornamental, for so many people that I know. Never trust bermuda grass. Kill it and destroy it every chance you get. Remove it from your growing beds, and have mulched pathways between your beds and around them in order to keep bermuda grass away from them. If I ever meet Mother Nature, I think the first question I will ask her will be about bermuda grass and it simply will be "Why? Why? Why? Why did you turn bermuda grass loose on the world?"

Dawn

Here is a link that might be useful: Soil Jar Test for Texture/Composition

This post was edited by okiedawn on Mon, Oct 27, 14 at 13:44

::Raising hand:: I'm another one who learned the hard way not to rototill bemuda grass.

Thank you for all the wonderful advice and information.
I apologize for taking so long to reply back. (The last week of October is one of my busiest weeks.) Today was a day to catch up on house duties--cleaning, laundry, etc.
I was able to work on the new beds this afternoon and dug out the grass/weeds on the outside of one of the beds and raked through the tilled soil--there's no way I can pick out every tiny root piece, though. I put down cardboard--forced it under the bed sides so that it extends outside the bed about 6 inches.

Our 3 new beds are a U shape. The plan it to kill the grass/weeds in the empty space in the U by using more cardboard and woodchips (or something similar).

Anyway, that's what I've completed so far.

I'm going to re-read your response, Dawn, when I'm a little more awake. It's full of good stuff. I'm sure I'll have more questions. It's killing me that I actually purchased some rolls of Bermuda at our last house, to fill in some spots that were bare after tearing up a deck.
:0

I have not read Dawns reply, it looked LONG! :)

But, please, please, don't just put cardboard and woodchips (or something similar) in the middle between your beds.

The bermuda will most likely NOT die, but crawl around under there, and go over in to your nice soft tilled area, and come up through there.

Best way to build a bed is to spray with round up and wait two weeks and see what of the bermuda died. Then spray what is still alive.

Repeat the above.

Of course, all this needs to be done while the bermuda is actively growing, not when it is dormant during the late fall and winter.

Then, best still dig out the bermuda stolen before adding cardboard, soil and compost for your new beds next spring.

I know, it is to late for this treatment, and for you.

Please, please, do yourself a favor and dig out the bermuda stolen.

Otherwise, you will likely want to quit gardening next August when your nice beds are covered in bermuda and need to be mowed.

Moni

PS, sorry to bear bad news like this.

First question.
It's about the composting of weeds/grass along with the autumn leaves using a lawnmower. Does the grass you dump on as a compost not cause problems? It doesn't seed in your soil? We don't only have Bermuda grass on our property. It's a combination of other grasses and weeds. I've just been hesitant to put grass clippings in the compost or use as mulch because I thought it would make Bermuda grass grow. Where are the seeds on Bermuda and weeds, etc?
I'm not sure I'm making sense.

We dug up a flower bed along the front of the house and really there have only been a few unwanted things that have sprouted. The Bermuda is only coming up along the edge of the bed--which I THOUGHT I would prevent with putting cardboard pieces along the edge. I've been pulling them up. The only other things that occasionally pop up are a dandelion (which I'll sauté with some garlic--yum!) and another annoying little weed that looks sorta like a tiny clover, but isn't. It's very little with shallow roots. That bed has remained amazingly clear of weeds and grass other than those few things. However, it's only been about 6 months. I did hand pick as many of the roots, etc. as I could when we made the bed.

So, if you were starting over, what would you do to prevent Bermuda grass? Obviously, it you're going to plant a garden you'll need to dig up a spot for it and that involves disturbing the grass and weeds, which apparently makes many new Bermuda grass "things" and exposes weed seeds to the light.
I probably won't use Round Up for personal reasons.
So, my plan is to till/dig up the ground, pick out as much of the grass and weeds as I can, and then put cardboard down and add soil and compost on top.
I'm sure it's a bad plan, but I don't know what else to do if I do not wish to use Round Up.
I have had a garden in the past, but I was blissfully ignorant. So much that I was proud of my huge okra until I tried to cook and eat it. Anyway, back then, I just dug up the bed, planted seeds, and picked weeds/grass as they came, and then enjoyed the food. I'm trying not to get too "stressed" about Bermuda grass and weeds, but want to learn from others as much as I can.

Hazel, I do use round up, but very sparingly. I won't use it, in areas I plan to plant edibles.

I dig it out. Two shovels full of soil and roots get turned, I sit down, and pick EVERYTHING out.

Then I repeat the process till I get tired of it. LOL... and in a few days, I get right back to it, till I have my patch as big as I want it.

If I really miss some bermuda, I dig it out the following year, as it appears. Ever once in a while, I will use a brush, and brush some round up on some bermuda I missed, and is to close to other plants to dig it up.

This keeps me busy over the winter, unless I am out riding my bicycle. :)

Where in Oklahoma are you? I am in OKC.

Moni

Moni, I'm technically IN OKC too. But we have a Norman address and are in Moore schools. It's a weird thing.
We bought our house last spring.
Are you north OKC or south OKC?

near 14th and Villa

You can email me through "my page" if you want to know more.

:)

Moni

If your compost pile gets hot enough, the heat will kill the weed seeds (including bermuda grass seeds) but generally won't kill the stolons of bermuda grass or of larger weedy grasses like Johnson grass. Having said that, some years I have thrown lots of Johnson grass and some bermuda grass onto a compost pile and it does eventually decompose. When I move compost from the pile to the garden, I am careful not to move any bermuda stolons or Johnson grass stolons with it.

As the texture/tilth of your soil improves every year, it will become easier to dig out the bermuda grass that sprouts. People who start out with sandy soil or sandy loam often can pull out bermuda grass fairly easily, or at least can dig it out pretty easily. If you have dense, compacted clay or rocky soil (like my brother's caliche clay soil), digging out the bermuda grass that tries to invade every year still will be a challenge, but it can be done.

Cardboard disappears after a few months---it either gets eaten by earthworms or it decomposes. If you want to use cardboard as a barrier to prevent the bermuda grass from invading a cleared area, put down new cardboard every year, and 2-4 thick layers are better than a single layer. In a rainy summer, I've seen very thick cardboard disappear in as little as 4-6 weeks. In a drier year, it lasts longer.

I will use a bermuda killer (Grass Be Gone), when it gets too entangled in my flower beds. If you don't have huge beds (unlike silly me) you can monitor your beds...just pull the grass anytime you see it. My problem is July and August. I don't want to spend time monitoring my beds, I want to set the water and run back inside to the a/c. :)

You can cut edges around the bed (think of a small ditch) that can help.

Lisa

I have much more problems with Bermuda in my mulch and compost pile than I do my garden. I don't compost a lot, but It is hard for me to get the heat up enough to kill the Bermuda, and if I do it just grows back from the edge again. I don't have a fancy way to compost, I just pile it on the ground.

Larry

You folks are so interesting. I love reading your posts and different experiences. Everyone's experience is different.

So...I will just do what I do (to build my garden) and create my own experience...with all the knowledge and advice you've provided. It will still be my own unique experience--like each of yours, but at least I know a few potential pitfalls that I can try to avoid. Or face and deal with the consequences.

Our three raised beds are completed. The pumpkin patch area is dug up, and the east large garden-yard thing I want to create was tilled up this morning. I've been able to rake through and pull out as much roots in the raised beds as I can...and put thick layers of cardboard down.
The pumpkin patch and east garden--not sure when I'll have time to rake through those.
The east garden is quite large, but I would like for it to be more of a yard--with different beds and pathways--no grass, though. I'm sure it will take years to build to my vision.

Larry, I just put my compost "bins" on top of think layers of cardboard and so far it seems empty of grass.

Thanks, everyone for your helpful posts!

There is a Ted Talk on YouTube by Mike McGrath that I thought was interesting. It is called "Everything You Know About Composting is Wrong"

Mike McGrath has been making me laugh ever since he was the editor of Organic Gardening magazine back in the 1990s, so of course I had to go watch the video. It was interesting. I do agree with his premise that all you really need is autumn leaves, and where he uses coffee grounds, I'm more likely to use rye grass clippings in winter because that's what we have. I think that food scraps/kitchen waste breaks down more quickly here than it does in his climate, and I throw them on the compost pile, but they usually get eaten by scavenging wildlife here on the first or second night after I throw them on the pile. I console myself with the thought that the scavenging wildlife surely is leaving its scat in various places on our property, so that the kitchen waste still ends up improving the soil somewhere.

His leaf blower prop made me laugh. We have had a leaf vacuum forever and I use it. I suppose that it also could be used as a leaf blower, but I've never used it that way.

A long time ago I read something written by J. Howard Garrett about using composted leaves to enrich soil. I don't remember if it was in one of his many books, on his website or in a magazine or newspaper article or his weekly newspaper column, but he said that the great thing about leaves was that they not only contain all the nutrients your plants need, but that they contain them in the proper amounts/ratios. I've used leaves like crazy for a couple of decades and I'll never stop. My dad always gathered leaves and put them on his compost pile, and I don't remember him putting much else there, but then, I was a kid and maybe I just wasn't paying attention.

I've read some of those composting books written by extremely knowledgeable people and some of them make composting sound so intimidating. I don't see any reason to make something harder than it has to be.

Dawn, I finally looked at that you tube about compost.

I don't agree with him all the way, but he does make some great points.

I do compost kitchen stuff, along with leaves, and all kinds of shredded stuff I put through my shredder. ;)

Moni

Here is a link that might be useful: you tube compost video

Moni,

I didn't agree with him about everything either, but some of his points were great.

His tomato book was one of my all-time favorite tomato books, and I laughed my way through it because his writing style is hilarious. Organic Gardening magazine was a lot more fun when he was the editor and there was some humor in it.

I'll put just about anything on a compost pile. Eventually it all breaks down, and in our climate, it generally breaks down awfully quickly. He is in a lot colder climate than we are, and I think his comments on how slowly some kitchen scraps break down reflects that.

Dawn