Stuck between a rock....and even more rocks
March 2, 2017 2:17 PM   Subscribe

Short version: Backyard has compacted clay soil with tons of rocks. What are the best manual ways to remove all these rocks and amend the soil?

Long version: We moved into a newly built house back in July. Yay!! It was way too hot to contemplate yard work then. This winter has been extra wet and rainy, almost always on weekends (in Arizona, crazy!!) impeding progress. Now our meager layer of dirt the builder dumped on top of the clay soil is pretty much completely eroded away, exposing ALL THE ROCKS EVER.

I'm interested in removing the rocks and tilling the soil to amend it with purchased peat moss and home-made compost. This would be in eventual preparation for gardening, and a small patch of grass for future kids to run around on.

I also need to start exercising, and gardening, or working towards a garden, is more interesting than any of my other readily available options.
Has anyone else done this? What tools do I need? What should my game plan be? Any ideas on what to do with the couple tons of rock that will be dug up?

Tools I own: Santa Angelo Bar, rigid rake, hoe, pointy shovel, flat shovel.

Tools I can borrow periodically: A husband, roommate, and three teenagers.
posted by sharp pointy objects to Home & Garden (15 answers total) 3 users marked this as a favorite
 
You really think you're going to grow a grass yard in Arizona? Is there a way to come up with a mix of plants that can peacefully coexist with the climate and soil you have (or will have with a little work)?

I don't think there's a trick to removing rocks, other than just picking them out. It's a drag. Maybe you can make a nice stone feature somewhere to make it feel like it was more worthwhile.
posted by acm at 2:46 PM on March 2, 2017 [1 favorite]


It might be easier for you (or your 'tools') to build raised beds and then bring in bags of soil (available at any garden center) to fill them. This saves you from having to dig, and what little soil you have is probably pretty poor, so you're going to need to heavily amend it anyway.
posted by spudsilo at 2:47 PM on March 2, 2017 [7 favorites]


I broke my back, three shovels, and two roto-tillers trying to amend some Texas soil which sounds very similar. I still can't grow anything in it. I wish I had gone with raised beds!
posted by TheCoug at 3:24 PM on March 2, 2017 [1 favorite]


With raised beds, you can also partially or completely line the beds to retain moisture. When we lived in LA on the basin's sandy substrate, this was a godsend: we were able to grow useful things like tomatoes and grapes, and we got a pretty sizable rebate for removing the (patchy, weedy, ugly) lawn that was there when we moved in. We had six beds and used crushed/decomposed granite between them (sort of like this). Since you have a digging bar, you can do even better by way of raised beds by digging the beds' plots down a few inches (or more) to give more room for roots to seek water that's shielded from daytime evaporation pressure.
posted by late afternoon dreaming hotel at 3:35 PM on March 2, 2017


I did this for a small patch of soil a few years ago with my new home, where the previous owners at one point put in landscaping rocks and then at some later point covered it with soil and mulch.

I built a soil sifter which worked well enough, but for a 50 square foot plot going a foot down it was a miserable two days of sifting (with breaks).

Getting to the clay layer for us also meant moist wet clay that didn't sift and break apart easily, so I had to break it up and push it through the sift - you may not have this problem in Arizona.

Amending the soil is a process that will take multiple years. In addition to doing soil tests, in my process I also threw in a lot of compost to get the bed ready for planting.

No idea what your budget is or the size you're talking about, but if you have the option may find it easier to hire a dirt hauler to dig out the first three feet and replace it with soil.
posted by Karaage at 3:43 PM on March 2, 2017 [1 favorite]


Adding compost is a very fine idea. I'd skip the peat moss and add greensand instead. It's the very best for breaking up the slippery plate structure that clay soils have.
posted by vers at 4:29 PM on March 2, 2017


You probably want lowered, e.g. waffle beds instead of raised beds, if you're going to be gardening in the dry season.

Pulling out the rocks is going to be a hassle, and heavy work, and probably perpetual -- there's always more rocks. The traditional answer is to use them as close to the source as possible. Paths between the waffles? Keyhole walls? Patio? What kind of rocks are they -- how big, how close to spherical, how many rough points?
posted by clew at 6:11 PM on March 2, 2017


While it's perfectly possible to grow a lovely grass yard in AZ, I don't plan on wasting that much money and water. A small patch to me is about 6x8', enough to put a small kid play structure on.

We actually live fairly close to, what was, the salt river bed. All the rocks are the smooth, round-ish river rock type. All sorts of colors, and ranging from about child's fist size up to about...well, the biggest one we found so far is close in size to my 18 pound Maine Coon kitty.

It sounds like raised beds is the winner. Which is what my roommate and I have planned for the next couple of years, but something has to be done to the yard to stop erosion, and after 35 years here I am completely done with gravel. So I was hoping to give the ground a bit more...permeability?

Thanks for the greensand and waffle bed suggestions too! They look cool and I will definitely read up on them.
posted by sharp pointy objects at 7:45 PM on March 2, 2017


You need a spading fork , one that has a square top you can stand on, do one or two square foot a day as long sunshine permits, gypsum transforms clay soil fairly rapidly still hard work .
posted by hortense at 8:33 PM on March 2, 2017


For compost, I would check with the waste management system in the city. In San Diego, you can get compost at the dump where green matter has been shredded and composted. It's not the best compost ever but that shit is cheap/free and plentiful. If you have some serious soil building to do, it might be the only affordable way to do it. You might also hit up Craigslist. Sometimes you can get stuff like horse poo, mushroom compost, or mulch for free. Beware, though. We got free mulch from a tree removal service and they dumped enough mulch in our drive to landscape a small city.

Also, in that dry climate, raised beds can be difficult to manage, they get hot and dry very quickly. Might want to consult your local garden store as to ideal height, soil mixtures, etc to keep them damp.

Build a shaker plate to rid yourself of rocks, like Karaage suggested.
posted by Foam Pants at 11:34 PM on March 2, 2017


Some rocks actually retain significant amounts of plant-available moisture - your soils sound pretty crap really. I know a vineyard here who removed all their rocks (they spend a fortune doing this) ... and then found their soils were freezing much earlier than previously: the rocks produced a microclimate.

What are the rocks like? If you hit one with a hammer (safety glasses pls), what happens? if it fractures easily or dents it'll prob absorb water. Weigh a rock dry, then soak in a bucket for a few days and weigh again, if heavier it absorbs water. In AZ I'd think you want every drop you can get in the dry season.

If they're compacted sure see if you can pry them apart but plants can do this for you too.
posted by unearthed at 12:50 AM on March 3, 2017


I've recently moved into a house with heavy clay soil and done some hefty landscaping and preparing of beds for planting. I'm in probably the exact opposite of climate to you (Damp UK weather) but after about 4 inches of clay soil I hot builders rubble embedded in clay of such a quality that I though about keeping it and making pots. TO sum up what I learned:

There is no easy way to clear ground but it is worth it in the end to clear at least a shovels depth. This will help when you want to plant things in the beds as there will be room to put the roots of whatever you've bought)


You need to put something in to break up the clay otherwise it will not absorb water and there will be puddles when it rains. I've tried sand and horticultural grit (essentially very small shards of stone) but what actually worked fairly good was coffee grounds. They also rot down in the soil and will help with water retention. It is a lot of work but mixing it with the clay will make the ground a whole lot better. You can get them for free from most coffee shops.


The least bad way of getting stones (and bricks) out of the ground is from the side so once you've dug down keep in the hole and then go sideways. If you can get under it to lever it up it should work better. Use the bar as much as possible as it is very difficult to break. I used one but I called it my demolition spear. I wouldn't have been able to remove the stump I had without it. It also might be worth getting a pick or a mattock. Normal procedure for me was dig down with a shovel to uncover a rock/brick clear around it with a trowel to see how big is was then wedge to spear under one side to lever it out if possible. The shovel isn't for moving the rocks that is a job for the spear. Once there was a hole deep enough and big enough to stand in just keep on expanding it from the top but keeping able to remove the rocks from the side.

Make sure you find somewhere where you won't mind a rock pile being for a while when you start to pile up your rocks. It will be larger than you think and also take much longer to get rid of it that you want.


Good Luck.
posted by koolkat at 8:18 AM on March 3, 2017 [1 favorite]


... what actually worked fairly good was coffee grounds ...

You can get coffee grinds for free from some coffee shops. I remember seeing such a bin at a Starbucks, but I don't remember seeing that anywhere else, but I'm sure there are plenty of coffee shops who would happily give you bags of grinds every day, if this is what you wanted.

It also might be worth getting a pick or a mattock.

Oh gods, yes! My family had a really rocky/dense clay acre, the kind of soil where you could use a jackhammer to dig a hole, pour water in to loosen the soil, and an hour later, the water is still sitting there. But we persisted, using a pry bar, my dad's preferred tool, but my favorite was a proper pickax. I was told elsewhere that a shovel is for scooping, while a pick is for digging, and I fully agree. I haven't used a wider-headed mattock, I imagine either would work well for breaking up the soil before you amend it with coffee grounds and any other natural materials.

As a teenager (and even now), I really enjoy the destructive capabilities of a pickax against tough soil. Your teenagers may, too. The bar is OK, and while it's great for prying up rocks such, you can't tear up the ground nearly so fast, as you can't get the hefty swing you get with a pick.
posted by filthy light thief at 11:36 AM on March 3, 2017


Any ideas on what to do with the couple tons of rock that will be dug up?

It sounds like they are somewhat nice looking rocks, you could probably give them away on craigslist.

After they are dug up, that is. You probably won't be successful trying to give them away for free if you want people to get them out of the ground themselves.
posted by yohko at 3:32 PM on March 3, 2017


If it's a large area it might be worth paying someone with a small excavator and a screen to get rid of the rocks in an afternoon, rather than do it by hand.
posted by Joe in Australia at 9:35 PM on March 4, 2017


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