So my general question is, we have a local landscaping company that sells "topsoil" which is decent enough stuff, we have pretty good soil in the Mohawk Valley (upstate NY) I will inspect it before purchasing, but the real question is, the landscape company offered to mix in whatever ratio of compost we want. My friend called and talked to them, he is getting the use of a small dump truck this weekend for us to run around getting fill and filling various raised beds for friends and family and our own.

If you were starting a bed fresh, how much would be ideal? 50/50? 60 topsoil 40 compost? 70/30?

When I first built my raised perennial herb bed, it was small, and I made my own mix from bagged products, with a very high ratio of organic matter. My soil was GREAT, and the plants loved it...but it sank. And sank. And sank. I've been put in the position of needing to dig up well-established plants, some of which had become small shrubs, in order to lift them up and add more soil.

Now that I'm extending that bed, I'm filling the rest with plain old "topsoil" (or maybe the place I got it from called it "loam"?), especially since all I've been able to find in my area is 100% dirt or 50/50 dirt and compost. I'll add my own organic matter in more sedate proportions at planting time, and mulch well.

If you have a bed that you expect to turn over or otherwise completely clear out at the end of the season, and you don't mind buying more stuff to top it up next year, then a higher ratio of compost would be fine. Then again, if you get "just dirt," you'll need to keep adding organic matter every year, right from the beginning, rather than skating along for a few years on the excessive amounts that you might have started with.

I suspect you don't need anywhere near 50% compost for good results. I think people consider an ideal amount of organic matter to be more like 5-8%, and if the topsoil you're getting really is good stuff, as you suspect, it may well have some in it to begin with. You wouldn't know for sure without testing, of course, though you could do a crude "jar test" to get a sense of it.

In short, I have made the mistake of starting with super-high levels of organic matter. I regret it, and I say "never again," or at least not for a perennial bed.

Lloyd

I do have a 2 pallet bin composting system which I plan on turning into a 3 bin system sometime soon. So yes, I will have annual compost to add every year, though some of my friends will have to buy thiers.

Thanks Pat

I second the motion.

Then layer regularly with organic mulches from then on out.

Also, I see what you did there. ;)

But.. whatever you have is fine to go with, and then from here on out , work that dirt, until it produces better than anyone else's in the neighborhood.... of all the people on the planet, I would hope we here on the Gardenweb, are at least the best in our prospective neighborhoods. ;-)