is it ok to put soil directly on grass when filling raised beds?

sophigirlMarch 5, 2010

I have been looking forward to starting my own vegetable garden ever since we bought our house back in November. We have built the boxes, figured out where to put them the back yard, and got a great deal on bags of compost. I am all ready to go, but have no idea how to actually start to fill the boxes with the dirt - there seems to be so many different views on that! We can't afford to rent a sod-cutter, don't own a tiller, and it seems that simply digging up the ground (with grass and all the roots still in it) would create a major weeding problem in the future. I have read that it is possible to simply place a layer of newspapers and leaves on the ground (again, with grass and all still being there) and then fill up the boxes. I, however, worry that the roots of new plants won't be able to penetrate the untilled, soil. Does anyone have any idea what is the best to do in this situation, or had similar experience? I need to add that the boxes are 6-inch deep.

Thank you in advance!!

Thank you for reporting this comment. Undo

We have a raised bed that was set up this way. We grow blueberries and tomatoes on this bed, with no problems. The bed is four years old. When you put a foot or more of soil over grass, the grass dies, and eventually it becomes part of the soil.

    Bookmark   March 5, 2010 at 7:47PM
Thank you for reporting this comment. Undo
the_gurgler(DFW TX 7b Sunset 33)

For all my new gardening areas that were lawn I do the following:

- A layer of cardboard (make sure to remove all plastic tape) or several sheets (6-7) of newspaper over the grass.
- Then put 3-4" of compost on top of the cardboard.
- Then 3-4" of mulch to top off the compost.

The cardboard, compost, and mulch breaks down and you have a fertile grass free section. You can usually plant beans or other low demanding plants in the area the first season.

I've used basically the same method for putting in raised beds. Just using a soil blend of compost, sand, and some of my clay soil on top of the paper. Then mulch the top.

    Bookmark   March 5, 2010 at 11:32PM
Thank you for reporting this comment. Undo

Yes. The local community garden here in Oregon uses the method described by the gurgler laying down three layers of cardboard, then compost at about 8-12 inches. For the paths around the beds, it's three layers of cardboard then thick bark mulch. The cardboard breaks down pretty quickly, but the addition of extra layers of mulch when needed keeps the weed seeds buried.

I have seen articles where gardeners have started new garden beds over grass by piling up their shredded yard waste in the fall, by spring in a wet climate it usually is almost ready for planting.

    Bookmark   March 5, 2010 at 11:59PM
Thank you for reporting this comment. Undo

Anytime you cover any plant material, including grass, and deprive it of access to sunlight that plant will die and then the soil bacteria will work on digesting it and putting it into your soil where they nutrients that plant had will be made avaialable to other plants. When the soil bacteria work on that now dead plant material they also loosen the soil and any plant growing above will be able to send its roots down and through where the newspaper once was with no problem.
I've made new gardens this way in soils that are clay based as well as soils that are sand based and found the soil, once the grass was digested, to be loose and friable, a very nice soil to work.

    Bookmark   March 6, 2010 at 7:29AM
Thank you for reporting this comment. Undo

Unless it it one of the invasive grasses, like Bermuda, covering it with a layer of cardboard, then the fill dirt, is all you need to do.

    Bookmark   March 6, 2010 at 8:07AM
Thank you for reporting this comment. Undo
dan_staley(5b/SS 2b AHS 6-7)

The cardboard separates any fungi working on the dead grass from your veggie roots, which is why it is done. Not 100% necessary, but better safe than sorry.


    Bookmark   March 6, 2010 at 12:19PM
Thank you for reporting this comment. Undo
rhizo_1 (North AL) zone 7

You can fairly easily shave grass to the soil level with a well-sharpened flat edge shovel. Unless your garden is very large, it shouldn't take much time or effort.

You'll be slicing the sod right through the crowns. Hold the shovel at a low angle to the ground and heave ho. You should be able to remove long swaths just like a sod cutter. The heavier the shovel, the easier it is.

    Bookmark   March 6, 2010 at 5:18PM
Thank you for reporting this comment. Undo
anney(Georgia 8)


Yep, you can put down the cardboard, newspaper, soil, and other goodies in your beds and the plants will grow. In your shoes, since it's brand-new beds, I think I'd want them down as soon as possible. Though you can plant everything whenever you get the beds laid out, I think you'd feel more secure if you can get them laid out now and then plant a week or two later. It gives things time to settle, particularly if you're unable to shave off the sod some way.

One guy on the internet showed how he removed the sod, turned it upside down so the roots were up, then put down the cardboard, newspaper, and soil for his raised beds. It was a matter of mixing "browns and greens" for fast decomposition of the sod and encouragement of earthworms, who apparently love the glue in corrugated cardboard.

    Bookmark   March 6, 2010 at 7:38PM
Thank you for reporting this comment. Undo

When you cover existing grass and "weeds" with newspaper or cardboard there is no need to cut it short, scalp the grass, turn the sod over, or anytihng else except just lay the newspaper, or cardboard, down on that grass. That will deprive the grass of access to sunlight and when plants are denied access to sunlight they die and if they are in contact with some soil where some bacteria and fungi exist those wee buggers will digest the grass and newspaper, or cardboard, and work them into your soil for you.
Invasive grasses can be a problem because covering those grasses does not necessarily mean the plant roots will die and possibly the grass will grow back from those roots. However, there will be considerably less grass than before.

    Bookmark   March 7, 2010 at 7:28AM
Thank you for reporting this comment. Undo

I notice that you live in the DFW area, so I would caution you to kill the grass before putting your expensive compost in those planting beds. It is very likely that you have one or more of the native grasses and they won't be killed by covering them up with paper and compost. They will be more likely to come up through the paper and your garden plants and will be much harder to to get rid of.

The best way is to water the area on a hot day and then cover it with clear plastic. Allow the plastic to remain for about two weeks to completely kill the grass. Then dig the area and remove all the roots that you can find. Water again and wait a couple more weeks to see if anything else sprouts. If it does, repeat the solorization process.


    Bookmark   March 7, 2010 at 5:06PM
Thank you for reporting this comment. Undo
kathyp(z9 CA)

As others have said, this is an easy way to start your beds. As for the invasive grasses - I have Bermuda grass, and started my raised beds 4 year ago with a thick layer of newspaper right on the grass. After adding spoiled straw, grass clippings, compost, composted manure, chopped leaves and anything else I could get my hands on, the beds are doing great. Yes, I have some grass poking through, but it's a small amount, easily taken care of with normal weeding.Curiously enough, the grass is usually coming up along the edges of the beds, which makes it very easy to pull out, and the loose crumbly soil ensures that the grass comes out all in one piece.

It's a great way to garden! Good luck!


    Bookmark   March 11, 2010 at 11:49PM
Thank you for reporting this comment. Undo

Is it okay to go ahead and lay cardboard in Ky? Temps have been in the 60's this week. Sunday they will be back in the upper 40's or early 50's. I want to start a small herb garden as soon as I can. Thanks.

    Bookmark   March 12, 2010 at 1:23AM
Thank you for reporting this comment. Undo

Our method for making new raised beds:

We use 2"x6"x8' or 10' boards for sides connected by strapping near the ends, usually 24-36" wide. We place the form over the area, then take a maddock and dig up the sod/lawn/grass whatever to break it up. We then fill with top soil, composted manure, and organic amendments. This has worked out very well for us and our plants grow great!

    Bookmark   March 12, 2010 at 11:16AM
Sign Up to comment
More Discussions
Bone meal....make your own?
Hey, I hate throwing stuff away, even bones, so I was...
Got tomatoes?
The organic Earthbox tomatoes have been coming in nicely...
Flowers and neonictinoids
I am in the Burbank California area. I have a small...
Broom corn millet-bulk for consumption?
Would anyone know of a source of bulk broom corn seed...
(un)Covering a Cover Crop?
I have a couple raised beds. Last fall, I planted a...
People viewed this after searching for:
© 2015 Houzz Inc. Houzz® The new way to design your home™