Not a dumb question. People differ on this issue. Traditionally, most people tried to get organic matter deep into the soil, especially when creating a new bed, avoiding roots close to already planted plants. Some folks now are talking about no-till gardening, where you just put your compost on top and let the earthworms do the mixing work.

I personally like the no dig theory, but you have to be more patient. ... Most "amendments" will have instructions on how to use them on the package.

Here is a link that might be useful: No Dig No Weed Gardening Book

I just posted on another forum asking a related question -- what should be added when you are created a new perennials bed out of space that is currently grass lawn? We will be cutting off the grass on top and will add mulch after it is completed, but what soil amendments are needed? Can we get by with just top soil to replace what is pulled off with the grass? should we add compost? Peat moss? We want to plant the bed now, i.e., in a month. Any recommendations?

-kathy

Kathy,
What I've done in the past that yielded good results was to cover the grass with newspaper and then cover the newspaper with 4" or so of mulch. The grass will die and the mulch will eventually breakdown and improve the soil. The best part is it's much easier than digging out a bed. The newspapaer sould be put down in sections, not individual papers. After about a month, you can dig through the newspaper to make your planting holes.

Ideally, digging out an entire bed about a foot deep and mixing in compost and maybe slow release fertilizer is the best solution, but it's hard work.

mixtim: Welcome to GardenWeb! For an established bed I would spread a layer of compost over the entire bed. I would not work it into the soil as this seems likely to damage existing plants. For a new bed I would likely mix organic matter into the bed and I usually throw in some compost when I plant something. I have been having good luck lately letting the worms do the work for me!

Kathy: What Da Kid said! I just started using the newspaper last year and I am a convert. No more digging up sod for me!! If you dig up the grass you just lost your best soil plus all the organic matter that the dead grass provides. I can also tell you that worms love the newspaper. Some areas I used newspaper and mulch and some places just mulch. The one newspaper covered area that I planted last fall was TEAMING with worms.

- Brent

I too believe in the newspaper and mulch plan, and the no dig compost on top plan. Both work well for me! Sometimes, digging in brings weed seeds that have been dormant to the top layer and into germination. That can be very frustrating!!

Okay, I am sold on newspapers. But, impatient as I am, if I spray the grass with roundup now (March), then cover it with newspapers and 4 " of mulch this weekend, how soon can I plant in it? I know I should have done this last Fall, but since I didn't, how long must I wait?

Thanks, all!

I am not here to debate the use of Roundup, as it is an alternative and probably better than digging up the grass and disposing of it. Roundup can only be used for plants that are actively growing, so I don't think it would be effective this time of year. If you did use Roundup you would want to let the grass die before covering it with mulch. That would probably take a week or two.

How fast will the newspaper and mulch kill off grass? Good question. 1 month? The newspaper approach does not require the use of Roundup. You don't have Bermuda grass do you?

- Brent

I roundup first, wait for the grass to die, then lay down 3 sheets of newspaper and an inch of mulch just to keep the newspaper down. Then i punch holes in the newspaper for what I plant.

However, if you are creating a fairly large bed, and want really vigourous growth the first year (you're impatient or need huge flowers for a wedding or something), you can also roundup, wait till the grass dies, then dig out the turf, dig a second layer down, put the turf way down in the hole (i put it upside down for good measure), mix organic matter like leafmold and some slow-release fertilizer or even some water crystals with dirt, then put all the dirt back in to fill the hole, then mulch and prepare to weed, weed, weed. Although I've seen studies that say doing this on a moonless night does actually supress some of the weed seed growth, it makes the neighbors worry.

One thing to realize is you'll create an island of good soil that your plants might not bother putting their roots beyond. Putting them straight into the cruel, hard ground keeps them from getting spoiled :>

If you add peat moss as your organic matter, be careful to mix it deep and well, otherwise it can suck water to the surface from the soil below, because it is such a water magnet. It also changes pH.

Does dig or not dig depend on soil conditions? If your soil is sandy like mine, you really don't have to dig way down and amend, although I do the first year on a new beds. I quit turning the soil years ago, even in my veggie garden, when I noticed how much richer the soil was in the unturned paths. The turning of sandy soil allows to much air into the soil, which fires up the digestion of organic matter. Heavy clay soil is a whole other matter, planting holes become little ponds because the water can't run off or soak up. Since it's been 30 years since I lived with clay, others would have better advice. Like most of the other postings, I mainly just pile the stuff on top between plant crowns and let it slowly rot. So far the plants haven't complained.

If you read the Lasagna Gardening books she says that you don't have to dig down into the existing soil when you plant. Just plant in the layers of organic matter that you've built up on top of your newspapers. Of course you can't really do that with things like roses or anything in large pots. When I made my rose bed I did a combination of digging good size holes for the roses and not digging anywhere else in the bed. Now all the places where I just layered the stuff are really easy to dig. I use whatever I have. Leaf mold, manure, grass clippings, fall leaves,peat moss, bags of humus or mulch. I lasagnaed a new bed at New Years when the weather was unseasonably warm. I planted my peas in it the other day. The newspaper hadn't rotted yet and the grass underneath was still alive so I added more leaf mold and raised it another few inches. I've never used Round up. I'd have to wait weeks that way. And what about all the stuff about if you dig when it's wet you'll ruin the structure of the soil. Lately there was a brief window of opportunity when it wasn't wet and I missed it.

What you incorporate depends on your soil. It can be worthwhile to pay a bit to have your soil analyzed by your local county extension office. At any rate, you can probably tell by looking at it whether it is sandy, or clay, or good crumbly loam. Around here, it's orangey clay soil, which has good mineral content, but holds water like a bathtub and is hard for some plant roots to penetrate. So I amend with leaf mould, compost, sometimes peat, and if digging a new bed, I also toss in some Osmocote. The soil amendments incorporate air into our soil, making it drain better. Good drainage is key for many plants. It's a good idea to double-dig the beds you are amending: that is, dig down at least two shovel-lengths. That will give roots plenty of room to stretch.

I let lasagna beds sit over the winter before digging, amending, and planting in them. That three to four months is ample time. I don't know how much good one month will do, but it can't hurt to try. Remember to wet the newspapers or it won't work.

I put in raised beds so I dug up the grass in the fall and flipped the clods of grass over. Then in the spring, I mixed in manure and soil conditioner, leveled it out, and then added a mix of manure, top soil, and soil conditioner over the top. I planted and then dressed it with coco mulch. 4 years later the soil seems to have a nice texture and everything seems healthy. No grass or weeds from before have poked through.

My two cents: mulching and compost do it all-ialbtc