Sandy soil generally has much less nutrient than clay, but add compost etc and it is excellent. Unfortunately- it eats compost like mad. You generally have the opposite issues that clay has- drains well but dries out fast, plants don't get wet feet, organic matter gets into the soil faster without tilling/double digging.

I have sandy soil, and consider myself lucky. Maybe it's the devil I know, and others know clay better.

I guess the bad memories of my two year experience with the previous sandy soil where I couldn't get the water in the ground. I guess I'll have to buy some compost since I just started a new pile at this new house. My soil seems better so far than the previous experience but compared to my black prairie loess that I had in MN, well, let's just say I miss it.

Sandy soil, because of the particle size and the pore spaces between the particles will not hold nutrients. They simply flow out when you do get water to flow through the sand. Sandy soils need lots of organic matter in the to fill in the spaces between the particels so both moisture and nutrients will be held in place.
Lots of organic matter is the only way I can hold any nutrients and moisture in my sand.

Sandy soil seems to do best if it's worked as little as possible because the web of microorganisms in it is very fragile. We tilled large amounts of organic matter into ours for five years without raising the OM level over 5%. So we've gone from tilling in spring and fall, to tilling only in spring, to not tilling all the beds but mulching heavily with compost, leaf mulch etc and planting into that. Planting green manure is supposed to be a great way to build up fertility in sandy soil but I don't know how to avoid tilling to incorporate it.

"Planting green manure is supposed to be a great way to build up fertility in sandy soil but I don't know how to avoid tilling to incorporate it."

You can't incorporate it into the soil, placed on top the soil organisms will incorporate it if you get out of the way. The process will silt up the sand and begin to hold moisture in the resulting humus if you don't till and cause it to drain away.

Planting aggressive green manure then mulching on top will help.

I'm not picturing this esther. Buckwheat will selfseed eternally if it isn't ploughed under, and how to plant into a ryegrass turf, and not have it seed forever? Do you mean grow the green manure, then smother with a heavy layer of mulch, then plant when it's dead? Trying to picture the timing of all this, given vegetable crops that are harvested at different times.

Our sandy soil is wonderful for many things - asparagus, strawberries, carrots....I'd sooner it than clay, if I had to choose.

I'm looking for roots to help hold the sand together while one is trying silt up the sand. With everything there are bad examples and good, I was thinking of annual rye because it is cheap then cover and smother and mulch (which could be repeated).

The question is often time, move a wild field and mulch with the hay and let it seed then follow with some kill and add organic matter. Not such a great idea but there would be many ways.

If you are planting a relatively small area dig about a foot or more and line with "cheap" landscape cloth which will silt up quickly and cheap product will all many roots to penetrate.

Buckwheat will self seed only if it is allowed to go past the best growth stage for a green manure crop and produce seeds. If cut just before flowering, at the best stage for green manure, there will be no seeds for future generations. Of course, this also means the bees do not get the pollen from the buckwheat.

I like that visual - 'silting up' the sand. It's helpful.
In my experience when buckwheat is cut down, even close to the ground, it makes new flowers close to the ground and becomes a pest anyway. Tilling seems to be the only way to avoid this. Or turning it over with a shovel, something I'd rather not do given the size of the areas we're amending.

There's another way to deal with sandy soil. Instead of trying to improve the whole bed, make trenches, fill them with thick layers of organic matter - compost, seaweed etc. - covering each with trench soil, and plant only in those. Some suggest lining the bottom of trenches with newspaper before filling with organic matter. We did this with a new garden and it's worked splendidly.

My soil is very sandy. I'm right along the banks of the Mississippi. I just add a lot of composted leaves/wood chips/anything else and my veggies/trees do just fine.

The first few years out here I diligently tilled in organic matter, every year, and never saw an increase in humus in the vegetable garden. But I did see that the perennial beds, which only got mulched every year, increased in humus, so I contemplated what was going on. Tilling sandy soils incorporates so much air that the bacteria digest the organic matter so fast none stays to become humus, but if it is plopped on as mulch the soil bacteria slowly work on that mulch and move it into the soil and finding more oganic matter to chomp on leave some in the soil to become humus. So do not till sand and expect to build up humus levels but instead just mulch.