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clay soil improvement advice sought
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Posted by MooQuack VIC, Australia (My Page) on Sat, Oct 22, 05 at 23:25
| Greetings,
I've done a bit of reading already about methods to try and improve the heavy clay soil I have in my yard so I'm not totally blind to the various options. However, I am wondering whether my soil is just too heavy for improvements to work.
I dug a hole, for example, to plant a new tree recently. The hole was 3 feet diameter by 2 feet deep because I was trying to ensure the hole was twice the size of the rootball. It was getting pretty tough-going so I filled the hole with water and left it for an hour so that the water would soak in and I could finish off the rest of the digging. Out of interest, I marked the height of the water with a small stick at the surface level. When I returned an hour later, the water level had dropped less than 1cm so clearly it was a bowl rather than a hole. The hole had not been left slick-sided by the shovel, in case you're thinking that might have been the problem - I made sure I punched divots in the wall with a pick before filling it with water.
Has anyone tried to improve soil this heavy before? Any luck? I know there's an option to raise garden beds but I also want some taller plants will will require soil improvements as well... |
Follow-Up Postings:
RE: clay soil improvement advice sought
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- Posted by ashmeri Cent. Qld.Aust. (My Page) on
Sun, Oct 23, 05 at 0:42
At our Old Place, we had heavy clay soil like that and I found it best to just make a hole as big as the pot to put the plant in and then Gypsum, blood and bone and mulch, mulch, mulch.
The more you disturb heavy clay the more it decides to become a brick and the hole will become a water well. After you plant water it in to get rid of air bubbles and then after that water it away from the original hole so that the ground stays moist not wet in the hole and the plant will take over from there with all the goodies in clay soil.
Marion |
RE: clay soil improvement advice sought
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Has anyone tried to improve this heavy soil? Yes - I have, but generally I would be adding new soil to the top and raising my beds, or planting a willow in that lovely wet patch.
Many of my beds are as you describe at present, and the plants that I have chosen to grow there are doing very well. Mulch and gypsum as Marion says, but also the correct choice of plant for the situation. My wettest beds are planted out with water loving irises, among prunus trees, that I hope will survive, and a pear tree that loves it. |
RE: clay soil improvement advice sought
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Hi MQ,
You have to add heaps of organic stuff and dig it through. Compost, manure, Blood and Bone, whatever you can get. I would also plant smaller plants into it as they will have a better chance of establishing. The smaller plants roots will be in amongst the good soil with a bit of a buffer before its roots hit the water and drown. The smaller plants roots will find their own way into the soil rather than putting a larger plant straight into the 'dam'. Raise it up a little if you can and add heaps of mulch. Every few months, mulch with more manure and the soil will eventually be much better.
Bryan |
RE: clay soil improvement advice sought
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| My son has very heavy clay. He just manures and mulches, manures and mulches etc etc. Except when he plants trees. Then, big hole, big as he can make it, gypsum, loads of organic matter then plants so that the tree sits on a mound about 15cm above the surrounding garden. His trees do well. Other advice is to stick, as much as possible, to plants that like clay. |
RE: clay soil improvement advice sought
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| All, Wow. 4 good responses in a few hours - this is why I keep coming back here!
ashmeri, I am trying to do as you say and water near the hole rather than in it. The concern I still have though is that the water is not going to get into the hole until it runs into it anyway - the soil is so heavy that any water applied to the surface simply runs over the top and refuses to sink in. Initially, back when I bought the house, I just thought the soil was hydrophobic because it was in the middle of summer and the water would not soak in. I did not realise until much later that water does not penetrate this soil easily.
Sparaxis, I should have mentioned in my original posting that this is not a wet spot down the back of the garden. My entire front and back yards are like this, and given the lie of the land, the hole I dug is actually at nearly the highest point (there's a gentle 1:50 slope over the entire property) so water should run away from it - certainly the area gets very hot in summer due to baking from the sun.
Bryan, I intend to fill out around this tree with small plants in a raised fashion as you've suggested so hopefully this will alleviate improve the top layers of soil over time and help the tree. Of course, the downside is that the tree may go with shallow roots to try and get into better soil and therefore it might work out badly but there's not much choice except to remove all the clay and replace it with garden soil, of course.
Raymondo, I thought I heard years ago that there was a problem with gypsum burning tree roots and that it was best when surface applied rather than dug in too deeply. Mind you, I can't find that same advice now I go searching for it. Any thoughts on whether the gypsum should be surface application only, or perhaps only down 5-10 cm at most? Would it still be useful, do you think, at 30cm depth? |
RE: clay soil improvement advice sought
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- Posted by ashmeri Cent. Qld.Aust. (My Page) on
Sun, Oct 23, 05 at 16:32
Moo, it does take time for the mulch and such to work, but when it does it is all worth the effort.
I always found the smaller the plant planted the better it grew, the roots will find their way and get going.
I forgot to say there are different clays too, some are better than others, on our present place we have terribleclay that is either a brick when dry or a sludgy mush when wet and it only goes down for about shovel depth then it is hard and almost impenatrable, we build up our new gardens with truckloads of imported soil.
I would love some of our Brigalow clay from the old place here.
Marion, who wishes you and your garden well. |
RE: clay soil improvement advice sought
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| Plant clay lovers and keep mulching to encourage earthworms, even go somewhere else to find the worms and bring them home. Let the worms do the heavy work. It takes time though. At least clay soil is generally nutritionally rich as water doesn't leach the nutrients. Plant lots and lots of potatoes, very good for breaking up soil :) |
RE: clay soil improvement advice sought
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| I have a boatload of worms in my compost bin that might be getting a holiday shortly. I picked up a handful of compost the other day and it was absolutely ALIVE with them. Thanks all for your assistance. I'll keep you informed as we improve it over time. |
RE: clay soil improvement advice sought
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- Posted by pepino Werribee Vic (My Page) on
Tue, Oct 25, 05 at 20:59
| Mooquack, do you know how deep the clay actually is. Around here it goes to about 2 ft and then we hit shale. Generally when planting a larger plant or tree we use a post hole digger to drill to this shale as it is porous compared to the clay and water will escape, albeit slowly. Other than that I recommend all the suggestions above. Also we water with drippers. It allows the water to penetrate rather than run off. Clay does have its advantages. It retains moisture well and also holds nutrients as mentioned above. Just don't let it crack! Best to cover it with a mulch of any sort to prevent it. I have just recently replaced some carpet in the house and cut it in squares for around the fruit trees. Placed it pile down and it seems to be doing the trick. Summer will prove its worth. |
RE: clay soil improvement advice sought
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| Not much of a suggestion compared to what you've already received but it occurred to me that, on the low side of any hole you dig, you could also dig a channel to let excess water drain out.... |
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