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improving clay soil

(19 Posts)
NotAnEMERGENCY Thu 07-Apr-16 16:11:20

I'm fairly new to gardening so please be gentle with me!

I have lots of clay soil in my garden and want to improve the drainage for the beds. (I assume it is fertile enough already so just the drainage that needs sorting out.) I do have a compost bin but the contents aren't ready to be used yet so what is best in the meantime?

Can I just use my cheap bags of multi-purpose compost from Lidl? Or would it be better to buy bags of composted bark or manure? (These seem to be more expensive.)

And where is it best/cheapest to buy these from? I have Morrisons, Tesco, Lidl and B&Q nearby but is online better?

I may well be asking more questions on this board in the near future - thanks in advance for any suggestions/advice!

WellErrr Thu 07-Apr-16 16:13:19

Watching this! I picked some actual modelling clay out of some beds yesterday sad

shovetheholly Thu 07-Apr-16 17:14:51

ABSOLUTELY you can use cheap bags of multi-purpose compost. Ideally, mixed with lots of horticultural grit and even a bit of gypsum (marketed as claybreaker). Definitely take a look at the 4-bags-for-£10 offers on compost and 4-for-£15 offers on grit at the gardening centre and B&Q. Also check out bulk bag delivery prices. It's worth costing it out per litre, because what looks like 'cheap' compost in small bags can actually be more expensive when you need loads of the stuff. And you do need loads to break clay - a depth of 3-4 inches ideally.

If you are growing veg, you can skimp a bit on the expensive compost and add loads of manure for most things (not roots, though). You can get it for free at a local stables. I go to one across the city where there is a Giant Pile of Poo. I put on my wellies, climb onto the pile trying not to fall over, and shovel well-rotted stuff into Ikea bags, then drive it over to my allotment. You get over the ew factor really fast, especially as it doesn't smell because it's well-rotted. Plus: FREEEEEE!

For fruit, if you have a brewer nearby, check out spent hops, also freely available. Raspberries will love you for it! Also, mushroom farms sometimes get rid of spent compost which is fantastic stuff, though many have started charging for this in recent times, the blighters.

Also, check out BOKASHI COMPOSTING!!!!! star star star <entire forum groans that I am mentioning this again>. See my thread (boring everyone senseless) below!

bookbook Thu 07-Apr-16 22:59:48

I will also add - our local council do free compost weekends , where you can go and help yourself. Worth asking?
Also Wilkos did very good deals last year
haha shove - I am just persuading DH on the benefits of Bokashi !

JapanNextYear Fri 08-Apr-16 07:39:55

Add everything you can find. All that shove holly said. I've got a clay allotment and used spent mushroom compost to improve the soil, it's v cheap and delivered straight from a mushroom farm where I am. It's also quite light to move round. Aldo collect leaves in Autumn and make a leaf cage and rot them down for a year before putting them on the soil.

What'll happen is you'll do all this and by this time next year the soil will have sucked it up and it'll look like you've done nothing. But keep on and in 3 or 4 years you'll really see a difference.

shovetheholly Fri 08-Apr-16 08:39:35

I'm tempted to drive up to your local council site and fill my car book!! grin

Believeitornot Fri 08-Apr-16 08:41:34

In the first year of our veg adventure with clay soil, we got some horse manure in.

Also dug the soil over every winter to break it up and added some leaf mould collected from the previous years.

We've just moved house and the soil is incredibly "clay-ee" so need to start again!

NotAnEMERGENCY Fri 08-Apr-16 11:23:50

Thanks to everyone for the friendly advice! smile

I'd heard of Bokashi before and it does sound interesting but we never really have meat to throw out.

I'm jealous of the free compost at the council! envy Ours doesn't do anything like that.

We have a number of big beech trees so am definitely planning to make leaf mould to use in the future.

With the compost, is the idea that I pile up 3-4 inches of compost/whatever on top of the clay and then mix it up with the clay? How deep do I need to mix it in?

JapanNextYear Fri 08-Apr-16 11:48:20

I'm quite a lazy gardener, so tend to just pile everything on top (3-4 inches) and let the worms and weather do the work. That works really well on an allotment, and you can make a planting hole in the compost whatever and put a pot grown plant in (so one of a reasonable size that will hold its own). I tend to start everything off in plots as so cold and exposed on the plot.

I appreciate that in a garden this may not be so aesthically pleasing and it makes it difficult to sow stuff directly if you were looking at sowing annuals, etc. But if you don't mind it not looking absolutely perfect - I'd just leave it on top.

shovetheholly Fri 08-Apr-16 12:40:38

Yep - that's what I do too Japan. The thing about leaving it on the top is that it suppresses weeds, thus saving effort AND improving the soil over time. Just shovel it on and leave it!

However, if you are thinking of planting into the soil fairly soon, I would make sure that you dig a really big hole for each plant (like, twice as big as the rootball) and add loads of compost and especially horticultural grit around the roots. This ensures that you don't have things sitting in pools of water on clay while the mulch is still on the surface.

loresho Fri 08-Apr-16 12:46:44

Following with interest, as I'm in a similar position and of similar experience in the garden!

I've already dug in quite a bit of compost (stuff from Homebase), and also some topsoil (which my neighbour suggested, but is that right?). Should I go back and dig in some grit too? Haven't started planting anything yet (not much from last year survived - it was just too wet this winter sad

shovetheholly Fri 08-Apr-16 12:57:05

Topsoil can help, but to be honest clay soil is actually quite good stuff to have already. It holds onto nutrients as well as water. It just needs a lot of stuff adding to get - and keep - it friable. Grit and compost have bits in that get between the clay particles and separate them out.

If you've already done a lot loresho, you could just dig in grit as you plant new things this spring? That way, you're delivering grit where it's most needed - to the roots. When you next mulch (and it is unfortunately a constant task that needs doing every year if you're on real claggy stuff), you can add in grit as well.

I didn't mulch enough last winter, and I can see the difference in the soil quality now. My garden is 5 years or so old on heavy clay, but not the impenetrable stuff (I have gardened previously where the soil was literally like modelling clay and could only be dug out in large blocks!). I'm making up for it by spreading bag after bag of compost over the next few weeks. It usually requires well in excess of 20 large bags, plus whatever I've made myself. I just do weekly trips to the garden centre til it's done.

MadamDeathstare Fri 08-Apr-16 13:05:18

Message withdrawn at poster's request.

JapanNextYear Fri 08-Apr-16 14:30:31

I've never added grit to mine. Just lots of compost, home made compost (which is quite twiggy) and occasionally a handful of grit in the bottom of a planting hole if I'm planting something that is going to hate being soggy all the time.

On really clay soil I think raised beds can work really well.

FiaMarrow Fri 08-Apr-16 14:43:04

We've got clay soil - we dug it over with lots and lots of compost and threw some bark on top. I chuck in a bit of horticultural grit when I'm planting anything. The plus side is it's full of goodness and most things seem to have done well in it. Don't let it get too dry in the summer though because the clay can damage plant roots - although you'd need a really long spell of hot weather to dry my bog garden out!

We can't dig down too far because there's a load of rocks and rubble under it so I grow my carrots in pots.

handslikecowstits Fri 08-Apr-16 16:40:51

All of the above advice about organic matter is good. I would add that whenever I plant a bulb or plant, I add horticultural grit to each planting hole.

hesterton Fri 08-Apr-16 16:46:16

The brewer thing is amazing - our local microbrewery are happy to give sacks of the musings from a brew (boiled grain) and the worms LOVE it. It's gradually training my London clay garden to behave!

NotAnEMERGENCY Tue 12-Apr-16 10:04:02

Right, I have added loads of compost and mixed it in a bit with the clay (I'm glad about the 'lazy gardening' comments as I didn't feel under so much pressure) so I'm now ready for planting.

I do want to add horticultural grit to the bottom of the holes I dig for the plants but where is the best place to get it from? According to the B&Q website, they do a 25kg bag, but our branch doesn't stock it and it's not available for home delivery.

Apart from buying in bulk, the only thing I've found is Westland 'potting grit' on Amazon (20kg for £15.69). There is also Westland 'horticultural sand' for the same price. Seems a bit pricey to me. And what's the difference anyway?

shovetheholly Tue 12-Apr-16 10:37:19

I get horticultural grit from the garden centre - it's much less expensive than Amazon at 3 small 25kg bags for £12. Be aware just how heavy a 25kg sack is, by the way - I find I can only just lift them out of the car and carry them round the back of the house. A sensible person would use a wheelbarrow, but mine's permanently at my allotment!!

I avoid adding horticultural sand now, but that's because I messed up in my last garden (south-facing) with it and not because it's a terrible idea. The house was very close to a clay works, so the soil was literally like potting clay. I added bags of sand, which broke it up - but it also made it seize in hot weather, so I got a rock hard, glassy surface on the top, which I broke several tools trying to get through! I find particle size of horticultural grit is just right to prevent this from happening.

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