Screening soil for raised beds?

Hi guys! I'm new here, permaculturing to some extent in Ireland. I'm chemical free organic for all i do around my small plot and on the verges of land my father owns which is conventionally managed grass pasture for beef cattle.

I have about 30 tonnes of soil that was dug up from a job that was done elsewhere on the farm. So we've decided to put raised beds in with what is great growing soil. Trouble is it's full of rocks. I was wondering if i should screen which i can do with forks of the grab on our tractor. And if so, how much rock should i take out of it, maybe leave smaller ones? Or should i just leave it alone?

Con Elder wrote: I have about 30 tonnes of soil(...). I was wondering if i should screen (...) with forks of the grab on our tractor.

Welcome to permies Con. 30 tonnes...I hope you're feeling energetic, because that sounds like an astonishing amount of labour!
What's your native soil like? (aside from the buried rubbish of course )
Clayey, sandy, loamy...
What's the soil you've brought in like?
Clayey, sandy, loamy...
Say you dig a shovelful of soil; how many rocks are we talking on average, and what sizes?
Can you lay your hands on industrial amounts of compost? I'd see adding organic matter as really important.
Unless I'm not getting the right mental picture, I'd want a heck of a motorised vibrating sifter-thing to de-rock 30 tonnes of soil

The permaculture designers manual has a simple drawing of a motorized rock/seed/soil sifter.

30 tons of soil is about 30 cubic yards (soil depending of course). That would make 60 yards of 3 foot wide, 1 1/2 foot tall beds.

You could use two sifters big enough to handle a loader-scoop at a time. Say one screen of 3-4 inch (old chain link fence might work) and one of 1/2
inch size. Put the screen at a 45 degree angle and it should mostly self-clean. The spoil from the first and second screen could be the foundation of the beds, if
you need more drainage.

I wish I had 30 tons of good soil and a tractor. Want to share? Although shipping to Hawaii might be cost prohibitive...

Alternately, you could make a heck of a lot of hugelkultur beds, and pick out the stones by hand as they come up. As long as you're not running machine cultivators, some rocks in the soil can't hurt too much, and will aid drainage and provide trace minerals for centuries. If the soil was growing well before it was dug up, it will probably continue to grow well even without sifting

Thanks for your replies.

It's not that timely. Really i'm just using grab of tractor (in attached pic) to sift through it. It just falls off by gravity and a little pull here and there, and stones often just roll off.

Soil is mostly clayey, very little loam. Finding a lot of twigs in it which is good. Also some fragments of plastic but not much. Given raised beds may only be about a foot high, it'll just save me the hassle later, and it gives me peace of mind. Also it just happens to have been taken from where my great grandmother grew her vegies, so it's a really nice experience putting my hands through the soil she would have handled (of course without the help of machinery ). There is'nt that many rocks, which is making the process go faster.

Agree Leila it will need a good dressing. I've another maybe 8 tonnes or so of really dusty stuff, the closest thing i'll get to terra prata around here.

Had'nt thought of that KC. It anyway has a lot of sod in it as it was dug recently, so i probably will be using most of it for hugelkultur and the base of other raised beds around the place. There's lot of minerals already underneath, and i'm not intensively screening so it should be fine.

It's definitely therapeutic working with soil anyway. Much better for the soul than feeding livestock and driving machinery. It's really cold here and half of cattle are still inside, as growth in pasture has been back a lot. Guess the world over is dealing with an unpredictable climate. As i prefer no till, i'll be happy just to get a lot of growing spaces set up this year. By next year, i should have a lot growing healthily.