I'm the wrong person to give you advice here, but if you want to repost in the Soil, Comport and Mulch forum you'll get lots of interest.

There's also a vegetable gardener from Cape Cod who often posts there (see the current Dry dog food thread on the first page).

Claire

lol Boy, there's a lot of forums here.
Thanks :)

It sounds like you have much more sand than I've got; I'm in the outwash plain in Falmouth, and we have a series of layers of sand, silt, and clay. Just turning the soil produces a fine grade of concrete, so I have to add lots of organic material wherever I want to garden.

A foundation seems like a great place to garden, and sand's a pretty good base for soil, although it's hard to build it up - it's a constant battle, according to friends who've lived closer to the beach than I do.

I think you're smart to keep the material piled up through the winter, so it can heat up in the center, which it wouldn't do if spread out over the sand. It should also dry out faster next spring, when you want to spread it.

I've found that seaweed takes forever to break down - something tough about those fibers. I've tried turning it into the soil, years ago, and I was able to see it clearly for years afterwards.

Personally, I'd plan to keep some of the seaweed separate - it makes a fantastic mulch. Since it's already mixed in, maybe you should try to get as much more of it as you can over the winter. You're going to need to mulch on top of your compost, because there will certainly be weed seeds sprouting out of the manure and some of the other components - it takes years for those to rot or be exhausted.

Good luck - please keep us posted!

Thanks :)
Falmouth can be nice. Sometimes I'm in woods hole for work, fine looking land.
Yeah, it's a different beast out here from what you have. Our soil blew into the ocean hundreds of years ago. Now it's just sand.
I have another compost pile (built a pallet bin) that I started in the spring that's looking pretty good. All the same stuff and the seaweed that I added in august and september is composting quite well.
I like the idea of growing in the foundation, no animals and should have much greater protection from wind (which we have a lot of out here). I wonder if because it's a min of 4' below ground level, if it'll help with frost. I was also thinking of making seaweed tea(?) in a couple of garbage cans next spring. I've read that plants love it.

I agree that it sounds like a great place to have a veggie garden and that you are off to a great start with your composting. I have very fine sand that I garden in (glacial lake sediments) so my soil will hold more moisture than yours, but it has really low organics and nutrients. I usually pile my well-composted manure (old horse manure) right on the surface 6-8 inches deep and plant into that and then mulch. When I was younger, I turned it in, but don't bother any more. If you have a truck or are willing to use your car's trunk as such (I line mine with an old sheet,) this is a good time of year to collect bagged leaves from folks that don't compost. Bring them home, run over them with the lawnmower, and then you have more organics either to add to your compost or to use as mulch next year, both to keep moisture even and to reduce weeds. Best if you check with the homeowner first and then you can ask if they use pesticides so that you know what you are getting. You can also check to see if your municipality runs a composting program.

Another source of mulch I have used on my flower and shrub beds (not veggies) is chips from the local line trimming crews. In general I have found that when I've asked they would rather dump in my yard that's close by than to have to drive to the dump with their chips.

I've been thinking about that concrete foundation, which should really mediate temperature swings nicely and maybe even allow you to push the zone a bit. Given the long mild fall season on the Cape you may get a longer growing season in there. Of course the late dismal spring may cut off some of that time.

A couple of thoughts:

1. You may want to be careful about planting close to the concrete wall itself where lime leaching out may make the soil more alkaline. Fine for some plants, not for others.

2. Placing some glass or clear plastic on top of an inside, sunny, corner of the foundation could make a good cold frame to extend the season. Or a transparent lean-to setup if that makes sense to you.

3. I wouldn't count on having no animals in there, although you'd probably not get the digging critters (foundation too deep). Jumpers and climbers may still get in (and get trapped, screaming for help). I'm imagining trying to lift out a panicky deer or pack of squirrels ....

Claire

I'm not on the cape, but, if I were to do this I would cover the entire area, as deep as possible, with seaweed and whatever else I could find for mulch/compost. I have been using sheet composting in my garden for years and cannot imagine an easier, more productive way to hold down weeds and control moisture (which I think will be a problem with sand for a base), as well as increasing fertility in your garden.
Ruth Stout wrote a number of books on this subject which are informative as well as a good read.