Using wood ash on calc soil

Like just about everyone else here, we generate loads of wood ash which we dutifully save. I’d love to use it in the garden and the veg patch as I know it’s rich in potash, but I’ve read that it’s not wise to use it on alkaline / calcareous soil. Is there anyone out there who lives in a limestone area who’s used wood ash as a fertiliser and whose garden has lived to tell the tale?

It has been hard work as we had to shift an old, buried cobbled surface where a previous owner had kept chickens. I suspect what soil there was had been enriched over the years in that particular area! In addition, part of the area had been used as a dumping ground for all sorts of rubbish (broken tiles, iron, plastic and rotten wood). The previous owners (British) had skimmed the weeds and planted straight on this and told us the soil was not suitable for growing vegetables. I have attached a photo of its current state.
Like you, we generate a fair amount of sawdust over the winter period. I put this into the compost bins. Some years ago back in England my younger brother used to supply me with lots of the stuff which I used to make a path. As this was replenished every year this was quite effective.
On a different subject,I am finding this year that all my potatoes are flowering at the same time even though there was a month and a half between first and last planting. I have early and maincrop plants all at the same stage. Does anyone else find themselves in this situation?

I suppose you don’t ship manure to Haute-Marne? :0) I’ve been resorting to scraping it off the road!

Hi John, thanks for sharing the secrets of your success. It’s very reassuring that it is possible to use the ash constructively, as your soil and geology sounds very similar to ours. I’d never thought of mulching ‘raw’ grass clippings - that’s a very good idea.

Do you think there’s any use for the sawdust, too? Could that help add organic matter over the long term?

Hopefully, it won’t be long before the only weeds I find a nuisance are the chenopodim and the convolvulus. You’ve done a great job to get to that stage!

I have been using wood ash on the vegetable patch for 5 years in conjunction with home produced compost and leaf mould. The vegetable patch (18m by 6m) is on clay soil that is over a limestone base. The leaf mould is acidic, and, so the books say, the wood ash is rich in calcium. As the wood ash is deposited, I hoe it into the ground so that it does not look unsightly but is also spread evenly. I use grass clippings from the verge to our lane as a mulch among the peas, broad beans and potatoes. As there is so little traffic (4 or 5 cars per day!), these clippings are unpolluted by traffic fumes and are rich in nitrogen so they enrich the soil. I use a 4 bed rotation system. Since cultivating this patch, I have increased the soil depth to 2 spade blades. The soil is also much darker than the surrounding fields. Judging by the productivity, this combination is working well. My only niggle is that after 5 years, I am still finding weeds such as chenopodium and convolvulus a nuisance.

Does not your local déchetterie make and give out for free compost, ours does in Mazamet

Thanks for your helpful replies. I’ve been rustling horse manure to improve the structure, as we can’t produce enough compost to spread as much as I’d like! Leaf mould as a mulch is a great idea. Our soil is alkaline, so ideally I’d like to drop the pH which is why I’m a bit concerned about using ash. Anyone tried mixing ash with something else and using it as a mulch? I thought that might reduce the potential it has to raise the pH. We’ve got lots of sawdust (from cutting the wood into logs!)

I was working on my gardening assignments and came across this -“Wood ash from a woodstove or fireplace (but not coal or charcoal) can be used in place of lime. Wood ash also adds potassium and some phosphorus, and usually has about a 0-1-3 (N-P-K) ratio”. They are talking here about raising you PH level, but if this is necessary you need to do a test. The page I was looking at was
I do remember reading that you must not put ash directly on the soil though! Saying that I use it as a slug repellent! I do put it in the compost bin as well.
I have clay soil at my new place nr Gaillac, last year we took trailer loads of stable litter and dumped it to form “beds”. This year when I have lifted this it is full of worms!! Very exciting, thinking of those worms taking all the organic matter down into the soil and creating holes for air and water! Great things, worms!

I have been putting it on the veggie patch right through the winter, but have no idea if I should or not!! I just assumed it would be good for the soil. I do need to find a cheap supply of organic material though, as our ground is sold clay and after just two sunny days, it is like concrete! Surprised anything can grow in it.