I'm puzzled by your soil too! sandy soil generally has good water infiltration and root penetration, but not this one!

I don't like to add raw grass clippings to soil. There are a couple of issues to consider. One, undecomposed organic matter in the soil is not helpful to the plants trying to grow there right now. Grass clippings in particular tend to be very hot - very high in nitrogen. They need to be balanced with cooler materials like dead leaves, low in nitrogen, while they decompose. It can be done in the soil obviously but this is what compost piles are for - to balance the nitrogen in the materials while they decompose. So they may not decompose at all while in the soil without a balancing material, or they may decompose so fast that they literally burn everything around them. And it's hard to get clumps of grass clippings to break up, the clumps tend to stick together and go anaerobic in the middle which is not good for the plant roots around it.

Second consideration is the herbicides some people use on their lawns. Or more correctly, that their lawn maintenance company uses. Some of these are highly persistent and while of very low toxicity to people and animals, can actually still be damaging to your veggie seedlings even after being eaten by a horse, pooped out, and composted as horse manure. So if they're on raw grass clippings, they'll affect people's seedlings.

If you have silty sand, it can compact to near-cement hardness. And the runoff problem can be solved my mulch over the dirt.

It sounds like sheet composting would be your best bet - just get ALL the gardeners to start adding layers of their OWN grass now (herbicide free), then leaves in the fall, and used coffee grounds whenever they can get some.

Can you start a compost bin or two on-site?

Thanks for the responses...

This isn't a vegetable plot. It is an ornamental garden. The plants are well-established for the most part. Although (my personal opinion) the plants are being moved around a bit too often for this dry hot weather.

I could make an onsite compost pile (or 20)nobody would try and stop me but I was looking for a quick fix. LOL People around here seem more interested in plants than soil. I like dirt so am sticking to that part of the process.

I guess I have silty sand because this stuff is HARD. It is almost as hard as clay but when you do get the clods to bust they break up into fine pieces instead of chunks like clay does. The fine bits just reform into a hard layer once it is watered and left to dry.

The area is mulched but the water just goes through the mulch and runs off the beds and into the paths. We do water but I do not think it is a very effective system. I've been digging holes and trying to break up the top soil and watering into the holes instead of watering the top of the mulch or soil.

I guess I'll just make some "community garden" compost and keep picking out what I can from around the dump area to use to amend the soil.

I can "liberate" the grass clippings and hide them until fall and start a regular compost pile and maybe some leaf mold. I can find a place that is a little out of sight near the garden and get some wire fence from the junk yard and see what happens.

Thanks again.

Sounds like you have silt, not sand. Sand can't be compacted, or should I say, won't agglomerate. Silt acts a lot like clay...water runs off but will break up easily (when dry) in comparison.
Adding organic matter is always a safe thing to do for any soil type, but nutrients won't be available to plants until broken down. Grass clippings are OK but not long lasting. If you have a steady supply, better to make compost using twigs, leaves, newspaper if available and then incorporate the resulting humus.

If water flows through the mulch but is then repeled by the soil and runs off and not into the soil then you need to get some organic matter into that soil. I have seen, rarely, where the Soil Food Web cannot incorporate the organic matter in the mulches into the soil unless some OM is first worked in and that appears to be happening here.

I've never had anything but clay so when the soil felt "sandy" I just thought it was sand. Funny. I keep saying (to whoever will listen) that my yard (and the community garden) must be an old river bed because of all the sand.

I've never really done any reading on silty or sandy soils but it looks like silt is a good thing to have. I'll just have to do some work on it. It certainly does not seem to be lacking in fertility, plants grow like crazy. It is just so dang hard to get water to go in instead of running off.

To tell the difference between clay & silt, take some of your soil (try to remove rocks twigs etc.), squeeze into a ball and let dry for a week or more.

Silt will break apart with your fingers or when dropped onto a hard surface. Clay won't.

"...but it looks like silt is a good thing to have."

Ehh. Doesn't have the workability of sand or nutrients of clay...or maybe I just cuss it 'cause that's what I have.

If you indeed have silt, the addition of sand can be a big help in attaining friability and permanently changes the soil triangle favorably (in terms of the gardener).

Adding sand to clay is a controversial suggestion and I'm not going there.

I know what clay feels like when I work in it. It is the difference between sand and silt that I am apparently having trouble with. It's basically a white powdery somewhat gritty substance that I THOUGHT was sand but I guess I didn't spend enough time at the beach when I was a kid. LOL Blame it on my parents.

So just out of curiosity what happens when you mix up silt and clay? Being in GA I do find the occasional pocket of clay but mainly it seems to be this white...silver...grey? stuff that I have.

Does it do good with patios and such? Can I use it as a leveling base for a patio or path or ummm a wall?

It isn't sand. I know sand well, it doesn't compact hardly, and doesn't dry in lumps or chunks or anything, just falls apart right away, most sandy soils have to be sopping wet to even be squeezable into a clump for a second.

Look up you county soil survey and go to the map sheets to find out a useful description for the location in question. My home garden is in an area of "coarse" sand. Most of the long-used farms around this county, OTOH, are in very fine sandy loam (silty). Hugely different, and massively more productive.

The people at your counties University of Georgia Cooperative Extension Service office will be able to help you determine what kind of soil you have.

Here is a link that might be useful: UG CES