Double digging

[raymondo]

Most of my block is solid clay. Rock hard in dry weather, unbelievably sticky in wet weather. A friend brought over his rototiller full of stories about how it would create a few beds in no time flat. Well, after an hour of working a small patch 1m wide and about 4m long and having just managed to chop the grass up he gave up!
My soil is simply not diggable straight off like that. Damn, it's barely pickable! I have had to spread lime, lay out thick newspaper and cover with whatever mulch was handy - grass clippings, straw, manure mixed in. I then planted into pockets of spent potting mix I can get free. The bed I made last year this way, is now diggable, though all I've done is fork it open.
I have also used weed mat. Just lay it out, pin it down and wait a year. So far I've made two good sized beds this way. This year they too are diggable but again all I've done is fork open the soil.
Double digging? Perhaps in 10 years' time!

[ottawagardener]

Sounds a bit like my mother's rock soil for different reasons of course but my mother's last garden was pottery clay. The trees loved it apparently or at least they were huge.

[canadamike]

My soil is like that Ray. I found waiting a certain time after rain, when it is les muddy, helps a lot. At my former house, i would put 3-4 inches of sans on top after rain, go at it with the tiller ( back tins is much better) and blend it, repass and so on. Much easier. Gypsum helps in clay to, it agregates the shit in small clumps.

[raymondo]

I use lime rather than gypsum as a flocculant Michel (it's the calcium that does the job) because the clay here is quite acidic, with of a pH of 5 to 5.5. And I use lime rather than dolomite because the stickiness suggests that the magnesium levels are too high relative to the calcium, though I haven't confirmed this with a soil test. I suppose I should.

[canadamike]

Chances are it is a fair assessment....we only get dolomitic in crushed rock form here, is it available powdered elsewhere?

[raymondo]

Dolomite is not a powder here, more like fine crushed rock.

[paquebot]

If you guys are looking for dolomite powder, it's not at the garden centers but at the health stores. It's a dietary calcium supplement for humans.

Martin

[raymondo]

Thanks Martin. It would never have occured to me to look there. Although I don't use in in the garden, I do use it in pots.

[Alan]

They do sell dolimite powder lime here at the local garden and hardware store. $2.60 for a 50 lb bag. Good stuff and irreplaceable in the worm house.

[maricybele]

My observations in blue clay - my clay soil here acts just like potters clay. I have 25 or so beds. 1 regular ground level garden plot and the others raised beds. Last fall I double dug 4 beds and for the first time I grew fantastic radish, beet, and turnip. Those grew fine close together. A few of the breakfast radish were as big as my hand and the white radish was as big as they should be. I have several raised beds that I made with cardboard underneath that I either double dug this winter or forked way down due to the success with the double dug beds. The digging fork makes all the difference for my back. I bought a mama digger last year, but don't use it like I do my extra sturdy digging fork for my beds here in suburbia clay.

[robertb]

There's a fabulous British TV series from the 1980's, 'The Victorian Kitchen Garden', still available on DVD. They recreate the sort of kitchen garden they had for 19th and early 20th Century stately homes. The natural soil around the one they used was about eight inches of soil on top of chalk. No way would that support the sort of intensive cultication they were using. Inside the kitchen garden, it was more like thirty inches of soil. No way would you do that without double digging. Mountains of horse poo from the stables next door would have helped as well.

Obviously we don't have twenty or more gardeners working twelve hours a day for a pittance. Once the garden was established, I wonder whether there was any need for it anyway, except as a way of keeping all those men busy all winter!

[ianpearson]

A good few years ago I noticed an interesting property of clay: there is usually a brief time of perhaps a week or so each Autumn when it becomes easily diggable. The time occurs when the clay has a specific amount of moisture in it, and crucially, the moisture level is increasing. The inflow of moisture seems to release the suction which holds the clay particles together, and soil breaks up easily and finely when the forkful is dumped down.

It does not work in Spring. The soil can have the same moisture content, but because it is drying out, the suction is drawing the clay particles more tightly together.

Needless to say, I had to spend many days standing in holes, sweating, digging clay with the wrong moisture content (damaging my soil structure) before I worked this out.

Now, I can relax as all my beds were double-dug long ago, and now I just need to tickle them with a hoe each Spring, and they are ready to go. The only energy I use is chasing people who STAND ON MY BEDS. GRRRR!

[maricybele]

In the acre garden plot I volunteer at the best vegetable plants grew in the double dug and the raised beds with trenches and the others that weren't double dug barely survived in this short wet season. This acre plot has an extremely high water table with clay you can throw.

At home, blue clay you can throw too, I have found my double dug beds to grow some of my best veggies. I only double dug once, and I now use a digging fork or mama digger fork to aerate and keep the top mulched with good results.

The difference is very noticeable. Here in the Northwest the best time is after a few days rain.

[steev]

I've found that the way to deal with my stock-packed, inorganic silt is to dig a ditch when the soil is moist enough to do so, using shovel or grape hoe or tine hoe or whatever implement of destruction seems to work, and then add organic matter to keep it from tensing up again as I refill the trench. This is hard labor, true, but the secret (aside from the aforementioned calling upon the Old Gods of Fertility and Biological Functions) is to get past the notion that I have to accomplish more than a small amount when that's really all I may be up for at the time. There is just no reason why every day has to be a twenty-yard day. Jeez, I garden because I don't want to work like in a factory. In any event, once the pioneer working up has been done in any area, the results are striking in terms of growth and productivity, and quite easy to maintain thereafter. I'm going to try trenching for an asparagus bed, but first getting some use out of it by filling the trench 3/4 with fresh horse poo to heat several inches of soil on top to jump-start some Spring veggies. I figure this will sink down enough so that when I harvest my greens or whatever, I can just mix it up and put asparagus crowns in at a good depth on top of some rich, soft soil. It's amazing how hard I work considering what a lazy bastard I am.