First of all...is the topsoil you already have, where you are locating the beds, any good.?

If it is good, you don't need as much new soil. I would think you would want to start with a nice amount of compost to get a jump start. I would then think you would want to mix it well with a few inches of the top soil.

Most folks don't have piles of excess garden soil sitting around waiting to fill a raised bed so bringing in/importing soil is extremely common.

There is nothing wrong with a screened topsoil provided it has been screened adequately enough to remove larger rocks (large than 1" diameter), big roots or chunks of wood and any other sort of debris - plastic, pieces of metal, etc. And I'd go with the leaf compost at a 25-75% ratio to start. That's higher than OM levels are suggested for inground soil but it will help to both improve drainage and retain moisture in the raised beds. Sounds contradictory but the two conditions really are compatible and that combination very desirable. It'll hit the suggested level soon enough with continued decomposition.

Lightly tilling the first few inches of the underlying existing soil is always a good idea but only if already bare of any lawn grasses and free of most of the weeds. If not, layer sheets of overlapping cardboard down first to smother and kill off whatever is growing there. By the end of the season the cardboard will have decomposed and plant roots will have started to disturb and penetrate the ground soil.

Pay attention to your plant needs during the season as you may need to supplement with a fertilizer. A compost comprised only of leaves will not have the range of nutrients as a mixed ingredient compost would and neither can be relied on as a complete and adequate nutrient source.

Thanks for the comments. We have hard red clay on which grass and weeds (mostly weeds!) are growing. It is hard to dig, but could put my teen boys to work. :)

If we put cardboard down, will the plants' roots have enough room to grow? We plan to grow an assortment of vegetables: tomatoes, cures, carrots, brocolli etc. the beds are 12 in deep, so 10 or 11 inches of soil. Can weeds and grass grow through that much dirt?

Forgot to add that I was thinking of mixing in Tomato Tone and Vegetable Tone when preparing the bed and throughout the growing season.

yes, that's plenty of room for the roots of the plants you want to grow. For most roots crops, I'd want a bit deeper but maybe wait on those till next season?

Either of the ferts are good but you don't need both - the differences are very subtle. If given a choice, I'd go with the Tomato Tone, as this supplies more of the specifics toms need but will also work just fine for the other veggies.

A good soil mix to look for is something like about 45 percent sand, 25 percent silt, 25 percent clay and 5 percent organic (compost, leaf mold, etc.) . There is nothing wrong with red clay except it does not have enough organic matter in it. There is nothing magical about "topsoil" either since it is simply the top 4 to 12 inches of soil from someplace.

hat ever you intend to buy take a good look at it before you commit and again when the soil is delivered to be sure you are getting what you really paid for. The terms "topsoil" or "garden soil" mean little.

Perhaps this article about "topsoil" may be of some interest.

http://msue.anr.msu.edu/news/the_shocking_truth_about_topsoil

kimmq is kimmsr

As mentioned if you are just building compost bins then it would be best to buy compost if you plan to grow this season.

Be sure to double check the delivery before they dump it to make sure it is what you want.

Using either cardboard or layers of newspapers to suppress the weeds is an excellent idea and means you could forgo the tilling or turning over part. Either should also provide worm food and permit any roots to penetrate below. By next season both should no longer be a concern. IMO that is a good thing.

You can also use the newspapers and/or cardboard in the walkways held in place by mulch to help suppress weed growth there. Use the edge of your beds to help hold them in place while laying things out. Wetting newspapers with water from a pump hand sprayer will help manage the papers until you can get the mulch or boards on top to hold them on a windy day.

I would avoid using landscape cloth anywhere near or in the garden. That stuff will be on this planet longer than all of us. Feel free to use 3 or 4 layers (or more) of newspapers overlapped inside the beds and cardboard in the walkways if you are concerned.

The reason I like newspaper and cardboard is they decompose and become worm food. IOW, they feed the soil - landscape fabric does not and just tears into pieces when pulling weeds which have rooted in it and they will.

Thanks for the comments! if i used 75% compost in my bin ( or even 50 or 30%), wouldn't that leave very little fill in the beds by the middle/end of summer? Its very hot and humid here, so things decompose quickly.

I wondered what Gardengal meant by that 25-75%. I would go with 1/4 - 1/3 compost by volume. Leaf compost should be great, also it doesn't hurt to use several composts. If you were going all bagged I would say to get several kinds to blend, but it's not essential.

If you can turn over or at least break up the clay before adding the raised bed soil on top, it will help roots as well as organic matter to penetrate into the clay.

The cardboard will turn to pulp fairly soon and roots will penetrate it just fine. As will the worms. Newspaper works fine too about 4 sheets was enough for my raised beds - which are about 6" tall over clay soil. I made them primarily for drainage in wet weather.

No, no, no!! Only 25% compost to 75% topsoil or garden soil. By volume (not weight).

I would have thought that my intent was obvious but perhaps not :-)

Lol, I thought you meant from 25 to 75%! Thanks for clarifying. :)