If you look closely at "topsoil" you will find that it might be about 95 percent of what you already have, the mineral portion of soil, and maybe about 5 percent organic matter and whay you need to get into your soil is organic matter, so what you need is compost. Spend you money on compost and don't be concerned about the other stuff.

So your beds are empty now? If so, I would get all the mushroom compost I could, and use that as the base for gardening soil. It depends so much on what's available locally. I would look closely at any advertised "topsoil" before buying it.

A friend of mine started a garden with a load of mushroom compost and it grew so well he had to jump back after planting the seeds.

Mushroom compost and composted manure will be pretty similar, you can use either one or both. I agreed with the other posters though, don't bother buying topsoil unless you really need to have raised beds. Let the compost make good topsoil out of what you have.

I live in the city, too, and managed to find a great source of rabbit manure from a network of foster homes that care for shelter rabbits. It's got a different balance of nutrients than cow or horse manure, but it's also not too hot, even when fresh, and it can be easier to find in urban areas.

I'd definitely take the mushroom compost if you can get it at a reasonable price, or at least a small amount if it proves to be pricy.

Some people like to tell you to never buy topsoil, but when you're filling a tall-ish raised bed, you need to use something...and mineral soil is a valuable part of the mix. You may "already have" mineral soil, but if it's buried under 16 inches of other stuff, how much value will it be? I fill raised beds with a combination of purchased topsoil and other things, depending on what's available -- but I'm also not trying to do a SFG, so take that as you will.

In my area, peat moss has a good cost per volume, but some people don't like to use it. It would help your soil texture, and would give you some volume to fill up the bed, but wouldn't provide much in the way of nutrients. If you use it, you might also need to add lime to balance out the acidity.

Some cities offer compost that's been made from tree trimming, collected leaves, and other such things. It's worth checking in your area.

My understanding is that the SFG method doesn't call for 16" of depth, so you might also consider filling the bottom half (or two thirds?) of your beds with something cheaper and less nutrient-rich, and the top half (or third?) with the good stuff. Or, depending on what you're using for the sides of your beds, maybe you could make them shorter this year, and taller next year, so you don't need so much fill all at once?

The SFG forum people might have more to offer in regard to your specific questions, too. Intensive gardening methods like that have some more specific nutrient requirements than more classic techniques.

I should probably add the house is new and unlandscapped (also in the plans for this spring...) So I'll be purchasing topsoil regardless. So should i combine topsoil:composte 50:50, 60:40 70:30 ?

this is all great feedback, thanks everyone !

Why are you "purchasing topsoil regardless?"

Steve

Wouldn't I need to lay a few inches of topsoil before putting down sod ?

You won't have the same result that my lawn had but some of the more southern people may enjoy the tale. The previous owners of this house really did a great job on the landscape and lawn. As the years went by we started noticing that the lawn was dying in patches. I pulled up a strip and discovered that the grass was only growing in the purchase topsoil/compost layer. They had just put the mixture on top of existing ground and did not incorporate. You probably can not grow zoysia in NB but incorporate the topsoil with the undersoil before putting down sod.

I am not a sod person but unless you need to level the ground why bother.

Best sod I have ever seen was at Joy Creek Nursery and it started on top of a driveway with compost to leave and seeded. Apparently the temperature is wrong to establish an even lawn so they worked arround the problem.

nbreau, what your soil needs, whether for a vegetable or flower garden, or a lawn, is organic matter. When you add organic matter to the mineral part of the soil equation, that you already have, you create "topsoil", because all that "topsoil" is is the top few inches, generally 4, of any soil, that might have some organic matter in it.
Just look for a source of compost, or leaf mold, and get that and add that to your soil.

nbreau, no one has asked you yet, was the "topsoil" scraped away during construction? Often a developer will remove this material and then one has to build up the level of the yard to meet the codes of the community. In our town, the homeowner has to build up 4-8 inches at times, with a portion of that being the thickness of the sod. If one were to take the advice of some and use nothing but compost, then in a few years their lawn will once again be below grade. And that is a whole different headache.

Advice based on incomplete parameters is next to useless and potentially costly.

Lloyd

nbreau,

You should look at what was done when the house was built. Here in Halifax (Hi there neighbour!), it was common practice a few years back for developers to take the topsoil away from sites where they were building homes and to give it to landscapers who would then sell it back to homeowners. This did cause big issues, but also made the landscaping guys really rich since those who did not buy topsoil to place their lawns on began having real problems with cinch bugs.

In any case, try and find out if your topsoil was stripped because if it was, then you will have to add quite the amount or incorporate organic matter into the soil you have. In a case where the soil you presently have is at the height you wish, then I would simply add organic matter to the soil as kimmsr suggests.

For your SFG, my suggestion would be to seek out a 50/50 mix. Some garden/soil places in our area sell it. It's a mix of garden soil and compost. I've seen the results of using such a product and it is amazing.

Do your research on mushroom compost. It's good for some plants, but not for others from what I understand.

Got room for compost bins? Start 'em up!! :O)