Allotments 4 All

OKay, following on from the leaves thread....why would I lime my lottie?  The only time I have ever limed anything was when I had run out of lemon to put in my G&T !

Basically because the processes involved in breaking down organic matter acidify the soil (this is referred to as the pH, which is the proportion of hydrogen in the soil solution and on the soil particles which hold nutrients 'in reserve' for plants to use eventually). As the pH decreases the amount of hydrogen increases resulting in greater formation of weak acids. Most of the bacteria and, more importantly, fungi involved in the breakdown of organic matter in a typical vegetable or fruit plot are adapted to a pH of roughly 6-7. Additionally, most typical fruit or vegetable plants are also adapted to take up nutrients at this pH too. 'Lime' or any calcium compound is most commonly used to achieve this because it displaces the hydrogen but combines with the hydrogen least of any other nutrient. This allows the hydrogen to escape into the atomsphere or leach out in solution. No G&T here I'm afraid. Not too technical I hope? I've tried to say this without using a 1000 words, Tim!

- with the exception of potatoes?

And dinna fash yourself, John - we love the long ones. = Tim

is there any cheaper alternative to buying lime? Perhaps a green manure crop which achieves the same?

- cheaper in money, perhaps, but not in time and space? = Tim

Green manures will also acidify the soil due the chemical processes involved- it's all decomposition.

Tim- potatoes prefer the same pH as most other crops. The problem is so does the scab!

Okaaaaaaaaaaaaaaaaaaay, I understand that, so when would I lime - in the autumn as I think was mentioned somewhere else, or in the spring?  I guess my first job is to test the Ph of the soil?

Fanks guys  ;D

 Don't attempt anything without a pH test. This is the most basic of tests. Many other processes in the soil are affected by the pH and will, in turn, affect plant growth. Many nutrients are unavailable to plants as pH decreases. This can cause a problem ultimately.
  Liming is best done in the autumn, but can be done in the spring if neccessary, so long as it throughly incorporated (by digging/tilling) and a brief period (two weeks minimum) elapses between it's application and those of fertilisers as it may cause nitrogen to be lost. It is also best done in spring on sandy soils where the retention of nutrients is low. I grew up on the Essex border and the soil was definitely not sandy so that may not be a concern for you.

OK, John - what the guides suggest, I think, is that pots can tolerate a lower pH? = Tim

PS I use a probe tester - as opposed to chemical - would you agree with this?

I find that a builders merchants prices for lime,sand & grit  are quite often cheaper than at the garden centre. Plus I prefer hydrated lime to crushed limestone seems to work better for me.

 Correct, Tim. But if scab is not an issue then a pH of 6-6.5 should be used to maximise nutrient availability.
   I have never used a probe, not even seen one 'in the flesh' that I can recall, so I can't really make any comment. Tax deductible laboratory analysis for me!

Yes, the best - but quite costly if you're doing 10s of samples?
So - herewith what I can afford - pH, and combined ph, moisture and light meters. = Tim

The old tip was to lime every fourth year, basically on the brassica patch on a four year rotation. Lime is useful to `bind` clay soil especially if one is into flocculation(sp)and also handy on light soils in wet areas as it is leached out fairly readily.

Soil probes give a rough idea but are not that accurate, and remember that liming means at  least a big handful per square yard-not a light dusting.

Stephan.

Agreed. Don't buy from a Garden Centre. Go to a Farm supplier (plenty around usually just outside town) and buy a 25kg bag. It does not deteriorate with keeping.

I followed the 'regular' teaching in  the 'olden days', but since the pH, all over, sticks at 6.5-7, there did not seem a lot of point? = Tim

Except, Tim, that it limits the ravages of club-root?

All best - Gavin

Point taken. Lucky old us, we've never had  it in over 40 years. (What have I said!!) = Tim

Our site had a daft old b....r - grew NOTHING but cabbages on his half plot for twenty years.  His wife worked in a care home, and he'd a deal to sell on his crop.

The mind doesn't even boggle - it revolts!  You can just imagine the perennial stench of over-boiled cabbage filling the corridors.

Daft old b....r he may have been, but he was a generous old s.d as well, and passed around his unused seedlings to other plot-holders.

He's long gone, but his legacy remains - go up to the site around the magical hour, and you'll see 12 foot tall club-root spores doing victory dances all over the place!  Some plots are riddled with it.

Long before my time - but I know that one of my predecessors was wise, and the other a fool.

Moral - don't accept brassica seedlings from D.O.Bs, until you've checked their club-root!

All best - Gavin

John - absolutely NO argument - just  to show what I've had in mind for some years.
It also adds a bit to the discussion? = Tim

:o hells bells!  Whose idea was it to get a lottie and grow veggies!  A gentle fun filled past time?  No, a chemistry, physics and biology lesson, with some horticulture and medicine thrown in!   :-/

Okay, I own a probe type tester thingy-me-jig, so will take it wil me next visit.  Everyone seems to grow a mix of things, so I am hoping the ground will be kinda neutral.  The soil is actually quite light and very stoney, but not sandy. Will let you know what my little doodah says. :P