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Community Garden, Sandy Soil and Grass Clippings

Posted by maryrecord GA (My Page) on
Sun, Aug 7, 11 at 10:02

I am helping out at a community garden. The soil is sandy and compacted. For some reason I thought that sandy soil was loose and well drained but foolie on me. I also thought GA had clay soil but I haven't seen any.

I don't really want to donate my own compost to the garden, 'cause I'm selfish that way. I do have access to an area where all the folks around here dump their yard waste. I thought maybe I'd find some compost or whatever if I poked around there but this late in the season it is mostly limbs.

There is a large pile of fresh to dry grass clippings that I could get to without causing an avalanche or something equally dumb. I'm wanting to incorporate the grass clippings into the soil and thought I'd check with the people here and see if it a/ would cause any issues b/ make the soil loose and increase the water holding capacity and c/ be ok with just grass clippings and no other amendments.

So if it is a good thing to do - How much grass do you think I should add. This is LEAN soil not much in the way of anything other than sand. I did find one bed that had a bunch of old mulch under a few inches of soil that the poor plants can't seem to penetrate.

The soil is very dry, the water just runs off and since there isn't really any water access it needs to be improved to minimize water carrying... 'cause I'm just as lazy as I am selfish. LOL

Thanks


Follow-Up Postings:

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RE: Community Garden, Sandy Soil and Grass Clippings

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.


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RE: Community Garden, Sandy Soil and Grass Clippings

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?


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RE: Community Garden, Sandy Soil and Grass Clippings

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.


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RE: Community Garden, Sandy Soil and Grass Clippings

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.


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RE: Community Garden, Sandy Soil and Grass Clippings

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.


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RE: Community Garden, Sandy Soil and Grass Clippings

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.


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RE: Community Garden, Sandy Soil and Grass Clippings

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.


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RE: Community Garden, Sandy Soil and Grass Clippings

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?


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RE: Community Garden, Sandy Soil and Grass Clippings

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.


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RE: Community Garden, Sandy Soil and Grass Clippings

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


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