How to garden in rocky soil
Share
How to garden in rocky soil
Plenty of blocks around here come with more rock in them than soil, and the first sign of it is usually somebody trying to get a tomato seedling in with a shovel and hitting something solid about 100mm down. It's frustrating, and it puts a lot of people off having a go at all, which is a shame, because rocky ground is a job rather than a dead end and you don't need machinery to get on top of it.
Use the right tool and the job halves
A shovel is the wrong tool for this and it's the one everybody reaches for first, which is why so many people finish the afternoon with sore arms and a hole they could have dug in ten minutes. A mattock is what actually does the work, because the cutter end chops through compacted ground and roots while the pick end levers rock out instead of you trying to scoop it. Follow it with a garden fork to loosen what's left and lift the stones out, and work the patch in sections with a break between them rather than trying to do the whole bed in one go.
Get the rocks into a barrow as you go, because a pile of them beside the bed will end up back in it, and the bigger ones are worth keeping for edging a path later.
What to put back in
Rocky ground is nearly always short on organic matter, so breaking it up and planting straight into it won't get you very far on its own. Compost is the main thing, dug through the top 200mm or so, and it does the double job of feeding the soil and holding moisture in ground that drains far too quickly. If the rock is sitting in clay rather than sand, gypsum will help open that clay up over a season or two, and it works slowly, so spread it and forget about it rather than expecting a result by the weekend. Then mulch the surface, because a rocky bed loses water fast and mulch is the cheapest way to slow that down.
The thing to watch for is worms. When you start turning up worms in a patch that had none, the soil has genuinely changed and you can stop worrying about it.
When to stop digging and build up instead
If you're hitting solid rock rather than loose stone, a raised bed is the sensible answer and there's no shame in taking it. You fill it with the soil you want, the plants get a proper root run from day one, and you've turned an afternoon of crowbar work into an afternoon of screwing timber together. Treated pine sleepers are the usual way to do it and we cut them to length at the saw bench, so you can turn up with a measurement and leave with the frame ready to assemble.
Give a raised bed at least 300mm of depth for vegetables, and more like 400mm if you want to grow carrots or parsnips in it, because a shallow bed over rock dries out almost as fast as the rock did.
What will cope while you're still working on it
Some things genuinely prefer the sharp drainage that rocky ground gives you, and hardy herbs are the obvious ones, with thyme being about the toughest of them. Local natives are the other good answer, since they evolved in exactly this sort of country and they want low phosphorus and not much fuss, which is what a rocky bank has to offer. Plant those in the difficult corners while you work the good bed up to standard, and you'll have something growing instead of a patch of bare stones staring at you.
Shop related products
- Brunnings Ultimate Dig It In Compost 30L. The one to work through a broken-up bed.
- Naturally Good Garden Soil, 50L. For filling a raised bed properly the first time.
- Neutrog Whoflungdung Mulch 20kg. Mulch that feeds the soil while it holds the water in.
- Easy Wetta Garden Mulch, 50L. Lets water through instead of shedding it off the top.
Did you know we also keep mattocks, garden forks, landscape rakes and bagged gypsum in the shop, none of which are on the website, along with treated pine sleepers cut to length at the saw bench. Give us a ring on (08) 8536 4333 to check what's on the shelf.
The rest of it is in our garden centre, and if you're not sure whether to dig down or build up, come and describe what you hit and we'll tell you what we'd do.
Read next
I own a mattock and I still reach for the shovel first, every single time.
Cheers,
Candeece
Follow our store Facebook page: Strathalbyn H Hardware
