I had the email below from Billy the other day and thought the answer would be helpful to a few people.
I took over my allotment last year, which hadn’t been used for years and was very neglected. I have dug over most of it but it is very compressed due to people before me just walking all over it. Also some parts are fairly clay like.
I was wondering, rather than rush it and try and do it all at once, what if the bit I was going to leave, was limed?
I’m of the understanding that lime breaks down the clay like lumps as well as lowering the Ph level to be acidic?
Should I then wait till end of year before using my plot or even wait till winter crop/spring?
Take Your Time!
First of all, when taking on an overgrown plot, the trick is not to try and sort it all in a day. That way ends up with an injured back if you’re not used to physical work. I’m a great believer in starting to clear at one end and moving down, keeping the area behind cultivated.
To help stop things getting worse, you can cover the areas you will get to last with black plastic (which I hate), cardboard or old carpet if allowed on your site. Cardboard is my favourite choice as it eventually rots down and does no harm whereas carpet can be a devil if the weeds go through it and plastic shreds into bits which can harm wildlife, especially birds, and lasts forever.
Use of Garden Lime
Chucking more fertiliser on will do little good as the nutrients just don’t get to the plant. However, increase the Ph with lime and it can have a miraculous effect. I always say there’s NPK and Lime as the important fertilisers because of this.
The side effect of lime is to promote flocculation. I love that word! It sounds as if it should be rude but it isn’t – it’s the process where small particles bind together to make larger ones.
Clay soils are made up of small particles that bind together into a solid lump whereas sandy soils are comprised of larger particles that have move gaps between to allow water and air in.
So lime certainly helps with a clay soil but the real, long-term answer is to dig over in the winter and allow the freezing action of winter to break it up into smaller sections. Pure clay is useless for growing as is pure sand. You need to add lots of organic matter to turn it into a decent growing medium. Organic matter acts like a sponge to hold water and provides a home for the myriad of beneficial bacteria and fungi that make the miracle of growing possible.
There’s more information on this in my gardening books and on the site here:
- Clearing a New Allotment – How to Clear a New Allotment
- You Have an Allotment! by Muntjac
- Garden Lime, Why Lime, When to Lime & How Much to Lime
- NPK Basic Components of Fertilisers