Creating a no dig bed on heavy soil
Stephanie newish gardener
Posts: 516
Hi
My veg plot is quite heavy soil that can get waterlogged as it verges towards clay. I'm thinking of trying to create a no-dig bed as I understand you can do that on heavy soil quite successfully. I'm working on the basis that if I put a load of compost on the top of the heavy soil then the crops at least get started in lighter better soil.
My husband turned the plot over the other day (I didn't think we'd need to do that) and now I'm not sure whether we should put a layer of compost on it now or wait for some frosts to break down what will be the base layer.
I've just had a look at Charles Dowding's no-dig website and he talks about waiting months to grow things, when I'd hoped to get started in early spring!
Does anyone have any thoughts please? We're in Aberdeenshire on the coast if that makes any difference to advice given.
Thanks
Posts
With heavy clay you run the risk of a pan forming, the roots act as if they are in a pot and don't go down into the clay. I would mix as much humous matter as I could get into the top six inches to give the plants a fighting chance. You can use compost, rotted bark or well rotted farm yard manure, or even mushroom compost, although mushroom compost tends to be a bit alkaline so you can't use it for acid lovers. Great for brassicas though.
i had this problem last year but chucked a load of horse manure on it in the winter ..let the frost get to it and it broke down quite well even after 3/4 months..though i only put sprouts in to start with which worked very well and ended up on my christmas dinner this year..compost has been added and hoping to get some sort of plant or veg in there this year.
If you've got plenty of compost or other organic material it wouldn't be a bad idea to try and mix some in with the clay, especially since you've dug it already. Then put a good thick layer on top. Should be fine to start growing early in the spring.
I garden on heavy clay that gets waterlogged. I have spent nearly 30 years digging in grit and then manure and my beds and borders now have beautiful loam. I don't have raised beds as such but the planted areas do rise above the grass areas and this reduces some of the problems with waterlogging. If you really do have clay and not just soil with a high clay content, I cannot imagine how a no dig system could succeed.
Oh dear, now I sound more virtuous than I am! It's about three quarters of an acre but in those years I have also had to give time to family, employment, other interests as well and battle with shortages of energy, strength and money, so I'm sure I haven't done as much as it sounded. What I should have said is that really poor soil cannot be improved in one or two big goes, no matter how much you add or dig. It needs years of love and attention, mulching, mixing, feeding and tending. No dig may be fine for light loam, especially if you mulch regularly, but I don't believe you can get much out of clay that way.
Hi, try posting this question on the Charles Dowding forum (sorry everyone) because he does usually answer questions on there.
Based on what he said at a talk I went to and some photos he showed, I think he'd say put a good layer of compost on there and start planting. He showed some photos of his old plot and his was thick heavy clay underneath the compost/manure layers.
Charles Dowding has proven that much of what has been said here is wrong. No dig is, oddly enough, no dig. Heavy clay soil can be grown in without digging, as he has poved by experiment. I have heavy clay soil, with lots of stones. Last year I converted a few more square metres by spreading four inches of good compost on the soil, pressing it down by placing a board on top and standing on it, then sowing seed. The carrots, parsnips and kale did extremely well. You need to spread compost as soon as possible, but just prior to planting is okay. The worms then drag the compost down. The top layer of compost gets the veggies off to a good start, and I had few issues with forking veg, unlike in previous years when I did not spread much compost on new beds. The only problem is that in late summer the soil became rock hard, and I harvested early parsnips using a cold chisel and club hammer. That is how heavy my soil is. Incidentally some of my parsnips weigh 1kg, such is the soil fertility. Quite how they grow in rock hard soil is a mystery. Last year I harvested 4kg of redcurrants from one bush, and I had not even picked half of the fruit. Clay soil is excellent, although carrots tend to split in heavy rain because clay holds the moisture.
I would advise against thin deep rooting veg such as salsify in clay soil, getting them out and cleaning them is not worth it, parsnips can be difficult, but worth it.
Digging may be needed if you have deep rooting perennial weeds, or large stones and rubble to remove. But I am surprised that my parsnips on very stony soil are not forking. As said earlier, I think the thick layer of compost allows a strong root to grow.
Thanks for the replies. Looking again at what I put, and after spending the day in the garden I think I have misrepresented the soil a bit, and the water issue isn't waterlogging as such, more just generally damp soil that isn't what you'd call free-draining. The soil is heavy, in that when it is damp (quite often) it really sticks to my boots in quite big pieces, but when I weed the bed, (that's digging, not night-time accidents!) the soil does break down into reasonably fine-medium earth.
It doesn't often dry out totally but it is effectively already a raised bed as it is within low walls about a foot tall. Below the heavy soil I believe is just more of the same. It's an old house which was once a watermill and the veg bed sits near to where the lade would have flowed, in fact the back couple of feet of it were probably once flowing water. It hasn't had water flowing (apart from a flood in 2009) since about 1875 but effectively the whole garden was once a flood plain as the burn runs round the plot.
Bizarrely we still have quite a mix of soil across the garden - it is dampest and heaviest nearest the house but much sandier in the far side away from the house. I decided to use this particular bed for veg as it's never really been cultivated and it seemed to be a reasonable place for a kitchen garden, it being nearest the kitchen
)
I grew shallots, dwarf green beans, kale and asparagus peas last year with varying degrees of success, though that could be my inexperience as much as anything else. It was also a good place for some hardwood cuttings from gooseberries and blackcurrants, plus a transplanted offshoot of a flowering currant, all of which have now been planted in their permanent homes elsewhere and all are happy. Oh, and there's a coriander plant from Tesco's doing fantastically well, still lush even now.
There is room between the current soil level and the top of the walls retaining the bed, so I thought it worth considering depositing a lot of compost and see how it might work on a no-dig system. Given that I probably didn't describe the conditions well enough first time round, it might be that I could get away with this method.
Thanks for looking and providing suggestions, all appreciated
Stephanie
Stephanie,
It sounds like a lovely spot. From what you say in second post it seems as though what you may have, is a high water table as the burn runs round and you have silt and sand in various parts of the garden (from past flooding?). If you read any good book that includes a chapter on soil etc what they all say is you can change the STRUCTURE of a soil by digging, composting mulching to improve fertility and aeration but not the underlying TEXTURE i.e. sandy silty gritty clay etc. So you have to work with what you have. Dig a small test pit cover it with a board or heavy plastic, see if the bottom fills with water, then you will know how high the water table is & then how high your bed needs to be to avoid trouble. The only other way would be to lay drains that run into the burn but that would be a huge amount of work.
I quite like a lot of what Charles Dowding says but it seems to me that he is growing in pure compost. If you have access to huge amounts of compost or manure it could be the way to go but remember no dig does not mean no work.
From where you are now I would let the soil get frosted, then as soon as it thaws get as much manure or compost onto it as you can. In spring you can decide whether to dig or plant straight in.
Good luck.
Completely agree with Iain above.
Think no dig sounds great but who has access( or budget) for that much compost!
Good luck with everything