Improving Clay Soil

[bonniethomas06]

I arrived home at lunchtime today to find three dumpy bags of lovely soil improver on my driveway - two of well rotted compost and one of grit sand.

This is all with the intention of lightening up and opening out my horrendous sticky clay soil. I have also got some gypsum on the way which I gather encourages flocculation of clay particles.

Has anyone had experience of adding either of these to clay? I know it will probably take a few years of repeated application to make a real difference, but it has got to be worth a try.

Slightly nervous of adding the grit sand as had a bad experience of adding sand to clay once (I basically created cement!) but this has quite nice rough large particles with a bit of grit included, so hoping it will do the job.

So nice to be starting with basics and spending a bit of time getting my soil in order before I plant anything - I have always raced in and planted in the past, then tried to dig in between things!

[Green Aura]

I've never added sand so can't advise on that. We used to rough dig, add compost and calcified seaweed as a top dressing and leave over winter. Or we planted spuds in other areas which broke it up a bit. Being generally bone idle (and lack of power tools) we only did fairly small sections at a time though.

No clay here. I quite miss my soil in Manchester. Here you can actually see layers of white sand as you dig down, presumably blown up from the beach during bad storms. That's assuming you can get a spade depth through the boulders (OK they're maybe more large pebble to cobble sized but still a pain).

[diggernotdreamer]

Having lived both on Berkshire clay and now Irish dab, I have had experience of improving clay soils. I have never bothered to put gypsum or grit into the soil. When I came here the lack of any compost or animals manures made me look at other materials and the local farmer brought me down a load of spoiled silage, I put that down on the cardboard where the beds were going and I planted spuds through the mulch, there was no question of putting a spade into the ground, it was hard wet clay. Once we had the chickens, I was producing good quality compost and I have just put some on top every year along with mulching with grass mowings. We now have beautiful friable soil that drain much better than the ground around it without any digging whatsoever.

[Thomzo]

Good luck Bonnie. Ive basically given up trying to improve my extremely heavy clay soil which is full of stones and am doing as DND suggested and putting mulch over cardboard to create raised beds.

[Flo]

We all have sticky clay soil here - it's a brick making area and the bricks are a delicate shade of pale yellow. It will take some years to improve your clay soil Bonnie. I've been down the route of compost, more compost and further compost for years. The grit sand did no good whatever but well rotted horse manure was a lot more use. Year in, year out every autumn for the last - well I'm on year 9 now and the soil is very manageable. Build your own compost heap, scrounge anything you can from friends and neighbours - hedge clippings, grass, cardboard, kitchen peelings, - great list here from Garden Organic who do a real good line in composting - their site has been worth its weight in compost for me!

[bonniethomas06]

I sympathise Zoe, raised beds might be the way to go. I have counted a total of 54 wheelbarrows of either farmyard manure or municipal compost (I know - it's not ideal but needs must. I dug a 6 inch plastic jelly baby out of the bag the other day!) that I have carted onto the beds. I have dug it in roughly and then turned huge sods over to let the frost (hopefully) do its work over the winter for the future brassica/root bed.

For the legumes/potatoes/curcubit bed I have manured it and sown some green manure, which I will dig in in spring.

Both have had a generous application of gypsum and bonemeal. Hopefully that will do the trick eventually, I am not giving up!

[Weedo]

I agree with most comments, gypsum is not a "silver bullet" for clay soil; it alters clay soil through chemical reaction which is directly related to the chemistry of the soil. Basically it disperses sodium and replaces it with calcium which disperses clay particles - only really works where your clay soil is high in sodium (sodic) and even then it requires water to disperse the residue. Gypsum can also lead to dispersal of other nutrients.

If you are really fixated on using Gypsum I would recommend having a soil test done first - preferably by an agricultural / horticultural laboratory.

Go with the added Veg, grow deep rooted or tuberous plants to help break up the structure (spuds are good) and get the soil bugs working - they are the key.

[Weedo]

Related (or not) to improving clay soils

I just finished cultivating a 60 acre paddock yesterday in preparation for sowing spring Lucerne. Last summer was very hot & dry and we had to hand feed most of our cattle so we used this as a "sacrifice paddock" as it has a clay band running through it. A sacrifice paddock is used during periods - either drought or flood - when we need to provide almost all of the herds fodder as hay; having a lot of animals clustering for food can destroy the surface soils and vegetation so we sacrifice one paddock to protect the others (Australian soils are far older and more delicate than British ones)

So we fed the hay out along the clay strip in round bales - 4ft long X 5 ft diameter X approx 600Kg each - where it was firm and less likely to be damaged; about 150 bales in all went out across around 10 acres. Guessing at 80% removal by cattle, this still leaves about 1800kg / ac veg matter left to the soil. Also, we have thousands of dung beetles busily digging holes up to 1.5 feet deep to bury the droppings. Now cultivating the area after spring rains the change in the texture, moisture levels and friability of the feed-out site, even down full depth of the plough, was amazing.

[Flo]

Your dung beetles moving the droppings will have probably been of more use than the hay though Weedo I'd think. But it's still a good message to add as much animal produced manure as you can obtain in a gardening context.

[bonniethomas06]

Thanks Weedo, I bow to your superior knowledge when it comes to the soil chemistry side of things! Hopefully gypsum hasn't done any harm if not any good, I gather it is quite inert in general and doesn't affect the ph?

Interesting to hear about the clay strip. I need to find myself some dung beetles!

[Weedo]

A combination of all factors I think - aside from burying the dung, the beetles dig a lot of fairly deep holes in the process; allowing air and moisture in which stimulates (and introduces) the bugs, worms etc. (I need to work on the worms a bit more) that convert everything. The hay concentrates the cattle and dung in an area then the beetles do the deep digging.

The beetles have been deliberately introduced (4 species) as self operating nutrient recyclers and can bury a full cow pat overnight- also helps keep the fly populations down. Again the trick is to keep the soil bioactive. A little like our digestive systems, keep the micro flora and fauna happy and in balance and everything else works.

Bonnie - I don't think the gypsum will have a great effect either way on your site; We Australians need to be very careful about our fragile soils, even small shifts in chemistry can have a big impact. Every climate and country has its own suite of dung beetles and most prefer particular dung - we have species that deal with Kangaroo dung and Africa has species that deal with elephant dung. We have to import some simply because we have imported the dung producers!

I have no doubt that they are around your area, keep an eye out around an outside light in late spring & summer, they are usually the typical scarab type beetle but with well developed forelegs for digging.

ASIDE - I am really enjoying this site - a whole different perspective on things and I am learning a lot. I will admit to using it to re-set my brain from the daily grind occaisionally.

[Green Aura]

Glad to hear it Weedo. We enjoy reading about our members from around the world. It's a bit depleted at the moment but growing again now.

The first time I saw a dung beetle was on a Disney film on at our Saturday morning matinee club, about 50 years ago (+/-). As there was nothing in the film to gauge the size of these things, I thought they were huge for years.