Advice to prepare very clayey sloped land for growing on?

GervisLooper

I was reading a book on it and it advises to dig trenches to drain the land. It explained it simply enough - dig until you get to the water ingress and redirect it via the trenchs to the bottom of your land and then you will be left with well draining land.

Sounded easy however when I started digging my experience was very different. Wherever I dug I was not able to find any veins of water. I did however find loads of compacted clay. Also the land underneath is dry or very nearly. So it seems more like the clay is so dense that water doesn't go through it and just settles on the top.

As such it seems like digging trenches would be futile since I was unable to find any consistent water draining to redirect.

I thought that instead I would be better served to just work on building above it is that a good idea? Just make lazy beds or terrace and put new good soil on top and let whatever is going on underneath just carry on doing its thing without affecting the stuff above?

The lazy bed method seems cheapest, just make raised mounds directing down the hill to promote drainage through the natural slope of the land.

This seems in line with 'no dig' which seems a popular and highly promoted growing method these days.

Would it be a good idea to see if I can order in a few truck loads of manure from a local farmer? Then spread and leave a couple months and plant on that mixed in with what little soil is underneath?

If I buy a load of manure to start and can then continue adding to it with compost I make but a load of manure could give me a head start?

ArbitraryRandom

If you have clay soil, then the issue will be the water from above your land running over the clay rather than soaking away - which trenches can still help with as they can 'catch' the water at the top of the slope and either allow it to soak away (because you've dug below the clay layer) or redirect it to the bottom of your land. 

French drain style: 

Then you can focus on establishing your beds and improving the soil quality in the areas you want to grow while still having firm/drier footing between them. 

CliveOfIndia

It depends to a large extent on the volume of clay - how big an area is it, and what's the depth of the clay?

If it's not too much then you can potentially improve it by digging in lots of well-rotted manure, garden compost, anything that's got a bit of bulk to it.  The thing is, clay in general is actually quite fertile, it's the texture you need to improve to allow for sufficient drainage and water-absorption.

Be under no illusions, attempting this for even quite a small area is very hard work.  Don't go in gung-ho thinking you can attempt it in one day - little and often, spreading the work out over several days or even weeks.  But if its feasible based on the volume of clay to be sorted, you can end up with a very productive plot.

GervisLooper

ArbitraryRandom said:

If you have clay soil, then the issue will be the water from above your land running over the clay rather than soaking away - which trenches can still help with as they can 'catch' the water at the top of the slope and either allow it to soak away (because you've dug below the clay layer) or redirect it to the bottom of your land. 

French drain style: 

Then you can focus on establishing your beds and improving the soil quality in the areas you want to grow while still having firm/drier footing between them. 

Thanks for the info. That makes some more sense then.

I thought the main benefit of the lazy bed though is that it allows the water to drain to the sides, so they are acting like drains, of a sort, themselves no? https://upload.wikimedia.org/wikipedia/commons/7/7b/Old_lazybeds_on_North_Harris.jpg

If it drains over the land and is on a slope then what is the issue? Won't it just drain to the bottom?

GervisLooper

CliveOfIndia said:

It depends to a large extent on the volume of clay - how big an area is it, and what's the depth of the clay?

If it's not too much then you can potentially improve it by digging in lots of well-rotted manure, garden compost, anything that's got a bit of bulk to it.  The thing is, clay in general is actually quite fertile, it's the texture you need to improve to allow for sufficient drainage and water-absorption.

Be under no illusions, attempting this for even quite a small area is very hard work.  Don't go in gung-ho thinking you can attempt it in one day - little and often, spreading the work out over several days or even weeks.  But if its feasible based on the volume of clay to be sorted, you can end up with a very productive plot.

Well it is about 2 acres! I don't have to improve it all at once of course and so can just leave whatever I am not working on to grow wild and chip away at it.

I have read that a quarter acre is a good manageable starting area which seems reasonable.

As for how clayey, I am just reading an article on the subject and one of the images looks very similar: https://images.tenthacrefarm.com/wp-content/uploads/20220406131702/IMG_1267.jpg

RAS

You drain land by intercepting the water at the top edge. Are you able to get into the fields above yours and alongside and check what's happening with the field ditches there? Once upon a time failing to clean your ditches before the autumn rains could attract a fine, but that ceased decades ago.

Water from your land may have been drained via land to the side if the upper edge slopes down, or via ditches down the side of your field? Where would water run when it leaves at the bottom edge? Is there anywhere sensible where you can add a catchment pond?

If the clay at the top is over very dry ground, before you consider breaking the pan, talk to someone knowledgeable aboutthe local geology. You could end up disturbing the entire slope and causing a slide. 

Next summer, mow or graze close and look for greener patches to identify possible springs?

GervisLooper

RAS said:

You drain land by intercepting the water at the top edge. Are you able to get into the fields above yours and alongside and check what's happening with the field ditches there? Once upon a time failing to clean your ditches before the autumn rains could attract a fine, but that ceased decades ago.

Water from your land may have been drained via land to the side if the upper edge slopes down, or via ditches down the side of your field? Where would water run when it leaves at the bottom edge? Is there anywhere sensible where you can add a catchment pond?

If the clay at the top is over very dry ground, before you consider breaking the pan, talk to someone knowledgeable aboutthe local geology. You could end up disturbing the entire slope and causing a slide. 

Next summer, mow or graze close and look for greener patches to identify possible springs?

It all sounds so complicated. Can I not just chuck good soil on top and forget about what is going on underneath?

RAS

You could just go for lasagne beds and let the worms do the job, a bed at the time. An allotment mate did that very successfully using domestic waste and woodchip, creating 30 cms depth a year. 

But if you do that the beds need to be across the slope, or on contour, with the ends of the beds overlapping so water running off one bed is captured by the one below.  Check out Charles Dowding, Sepp Holzer and any decent permaculture website.

GervisLooper

RAS said:

You could just go for lasagne beds and let the worms do the job, a bed at the time. An allotment mate did that very successfully using domestic waste and woodchip, creating 30 cms depth a year. 

But if you do that the beds need to be across the slope, or on contour, with the ends of the beds overlapping so water running off one bed is captured by the one below.  Check out Charles Dowding, Sepp Holzer and any decent permaculture website.

Thanks I shall look into those.

ArbitraryRandom

GervisLooper said:

If it drains over the land and is on a slope then what is the issue? Won't it just drain to the bottom?

You're the one who would know the issue that's being caused - because it's why you've been looking into drainage in the first place  

Generally speaking water drains to the lowest point, but that won't all be at the bottom of your land, because your land won't be an even slope. It will also be on any terraces or paths/dips, which can make them boggy (especially if you're walking on them when wet). 

The 'advantage' of having proper drainage (whatever that means for your land - as RAS says, there could be some old systems that need maintenance or a watersource on the land itself) is that you don't have to work to improve the soil all over the plot - you can focus your efforts on the areas where you want to improve the soil to grow things (meaning you can start small and increase over time). 

GervisLooper

ArbitraryRandom said:

GervisLooper said:

If it drains over the land and is on a slope then what is the issue? Won't it just drain to the bottom?

You're the one who would know the issue that's being caused - because it's why you've been looking into drainage in the first place  

Generally speaking water drains to the lowest point, but that won't all be at the bottom of your land, because your land won't be an even slope.

Well I wouldn't know because I am not sure what I am looking for yet. That is what I am trying to figure out.

Hmm so the puddles could have drained from above, rather than rainfall and just got caught there? I think the current ones are from the snowfall and subsequent thaw mostly.

There are loads of rushes all over the places in big patches but strangely these don't seem to be the most boggy parts, some bits are but more is the dry clayey soil mentioned above.

There is also a trickle stream in the middle but that is far from most of the rush growth and actually I think that is pretty much clear of rushes and is is a dip between two peaks of the land.

It is all on a gentle southward slope but two mounds and very slow trickle steam which just gets absorbed into the land between top and coming out at the bottom, in a gentle dip between them both. I guess that shows at least that part drains somewhat as the water is not visible on the top!

As for clearing the existing long grass and reeds and other dross can I make squares with spade and tip them upside down? Will what was growing above before die or will it grow back doing that?