Using Wood Ash in the Vegetable Garden

, written by gb flag

Wood ash or potash for the garden

Bonfires are a contentious issue, what with smoke and global warming. Personally, I love them, though I go for the fast and furious approach of an incinerator, piling everything in and (a personal best) achieving a spurt of flame two-foot high from the chimney. Reservations aside, a fire gives you the great satisfaction of getting rid of perennial weeds, branches too thick for the shredder, and diseased material while, at the same time, producing a valuable by-product: ash.

Wood ash (as opposed to coal ash) can be a great addition to the garden. It contains potassium or potash (they’re not identical but - scientists look away now - the terms are often used interchangeably), and potassium is a vital nutrient for crops.

Just as it does in humans, potassium regulates plants’ water balance (so tissue is firm and juicy), and has a part in transporting food within the plant and creating sugars and starches. Without enough, vegetables are more vulnerable to drought, frost, pests and diseases.

By now, I hope you’re reaching for the matches. However, bonfires aren’t the only source of ash and the increasing popularity of wood-burning stoves means that more people have to dispose of a lot more ash. In fact, a cord of wood (the standard unit of firewood in Canada and USA, measuring 4 x 4 x 8 feet (120 x 120 x 240 cm) is likely to produce around 25 lbs (over 11 kg) of ashes. Ideal for the garden? Well, yes, except you can have too much of a good thing, and you do need to think about where you put it.


Add Ash to the Compost Heap

Wood ashes make a great addition to the compost heap, where they’ll aid fertility (most of the nutrients needed by plants are contained in them to some degree). If you have a lot, don’t add them all at once as they are alkaline and raising the pH too much will affect the bacteria and worms at work. It’s better to keep the ash in a nearby container and sprinkle on a layer every so often.

If you tend to compost a lot of acidic material, such as fruit waste, the ashes will help to keep the compost at a lower pH and reduce the need to lime the vegetable plots at a later date.

Wood Ash as a Substitute for Lime

Speaking of liming, because ashes are alkaline, it is possible to substitute them for the usual ground limestone. However, home-produced ash isn’t a standardised product, which means its content will vary.

Hardwoods, for example, generally produce more ash and contain more nutrients than softwood. According to the very thorough information from Oregon State University Extension Service, ash from a cord of oak will provide enough potassium for a garden 60 x 70 feet, whereas a cord of Douglas Fir will be sufficient for a garden 30 x 30 feet, while both will raise the soil pH slightly. Bonfire ash is even more variable, because of the mix of plant tissue.

Like the potash content, the calcium carbonate content will also vary (although it’s unlikely to contain more than half that of ground limestone), so it’s a good idea to test the pH of your soil before adding the ash and three to six months after, to check on its effect. It wouldn’t hurt to check up on the potassium content while you’re at it. There’s no point in adding potash to a soil that’s already high in potassium, as too much can affect the plants’ take-up of other nutrients.

Wood ash for fruit crops
Wood ash provides potassium which is essential for fruit crops

Where Not to Use Wood Ash in the Garden

Being alkaline, wood ash obviously isn’t an ideal addition if your soil already has a pH of 7.5 or greater. There’s no point in spreading it around acid-loving plants such as blueberries. Nor is it recommended for areas where you intend to grow potatoes (much though they enjoy potassium) as increased alkalinity can encourage the fungus, potato scab.

It’s also worth remembering that potash is extremely soluble, so keep it absolutely dry before you use it (this includes before adding it to the compost heap). Leave your ashes out in the rain and all the potash will wash out and you’ll be left with a sticky and fairly useless sludge. If you pile a large amount of ash in one area, you also risk over-liming that area and damaging nearby plants.

Adding Ash Direct to the Soil

All this sounds rather alarming, but I don’t mean it to. Those of us who have the occasional bonfire won’t be damaging the soil with the small amount of resulting ash but rather adding a little of one of the nutrients that plants use most.

Sprinkling ash straight onto the soil also deters slugs and snails (the moment it gets wet, this effect unfortunately vanishes). I haven’t tried it myself, but some recommend sprinkling ash in the drills when you sow carrots, and dusting it on turnips to keep carrot and turnip fly away.

I generally add ash to the soil in spring and autumn, but it can be spread it around at other times whenever it’s available and you might as well if you know you can’t keep it bone-dry. Root vegetables such as carrots, parsnips, peas and beans (pods are a better weight and colour) and fruit all appreciate potash.

Regarding fruit, if you have only a little potash, it should go to dessert apples, redcurrants and gooseberries first, then to cooking apples, pears, raspberries, blackberries and strawberries. Plums, apricots, cherries and blackcurrants appreciate a regular sprinkle, but don’t need it so much.

In summary:

  • Keep ash dry before use.
  • Test your soil before spreading large amounts around.
  • Use it in particular around root vegetables, peas and beans, apple trees and soft fruit bushes.

By Helen Gazeley

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Show Comments


"Will it be detrimental to locate my mid-winter burn pile (branches, perennial weeds, etc.) in the middle of the veggie garden? I intend to later spread the ashes (and save the lawn)!"
bonnie maresh on Friday 18 November 2011
"We use wood and a bit of coal on our open fire, can I still use the ash even if it contains some small part coal ash?"
Rebecca on Friday 18 November 2011
"Bonnie, that sounds like a good idea to me. You can pile up the branches etc, set fire, then spread the ashes straight away. Be careful that the perennial weeds don't regain a foothold in the soil while waiting in the pile to be burnt, and it would be better not to leave the ash waiting to be spread as any rain would wash the potash down into that small area beneath it. Rebecca, this is a perennial problem. The general opinion nowadays is that because of the levels of sulphur that coal canb contain it shouldn't go on the garden. Back in the time when coal fires were common, the ash and cinders would be used for paths in the garden. My personal feeling is that if it's only a small amount of coal ash in proportion to the wood, then it's probably OK, but I know others wouldn't go near it. "
Helen Gazeley on Friday 18 November 2011
"I grew my first garden ever last year. Bucket list item, check! It is 73 x 40 and located over the spot I would usually burn my yard debris. I have burned in this approximate spot, give or take twenty feet, since 1983. After tilling the new garden, I tested the soil in a grid pattern over the entire area. I was surprised to find that only the last burn location from a month earlier showed a variance of around 6.5 to 7.5. The pile was about six feet high and twelve feet in diameter and consisted mostly of silver maple and some pine. I made note of this spot as my plan was to grow five, forty foot rows of corn right over it. Results: I could see absolutely no difference in plant health, color or height. The Burpee Early and Often Corn I used all grew to about nine feet. I used Miracle Gro through a drip irrigation system. Most of the corn had two and three tillers and each plant had two to three ears! Unfortunately none was edible! It was the worst tasting corn I have ever tried to eat! What did I do wrong? I called Burpee but they were no help at all. Oops, sorry I went off topic but now back to the subject. My advice as a beginner gardener is; go ahead and burn baby burn! If not for anything else, you can save your lawn. My common sense is telling me that earth worms will be able to move away from the heat but the tiny little bad nematodes nearest the surface will fry which I think is a good thing. Plus you will save a couple dollars on lime expense. I am entered in GrowVeg’s garden contest. You can view my garden plan here - "
Larry on Friday 18 November 2011
"We don't use coal, but do burn wood occasionally and spread it when available (in small doses). I'm just wondering if the ashes from a charcoal barbecue feast (as opposed to 'proper' coal) are ok to use too? "
Kimberley on Friday 18 November 2011
"I live in Fairfax County, Virginia - USA. It is illegal to have open burning of brush piles, etc. No leaf burning either. It has been determined that open burning is quite bad for the environment and I see no reason to add to poor air quality that already causes many health issues. Personally, I am happy to comply and will spend a few dollars on a bag of lime without complaint. For me, organic gardening is a way to decrease my negative impact on the environment - not ADD to the existing burden."
Denise on Saturday 19 November 2011
"Denise, you are certainly entitled to your opinion which is also the opinion of our great law makers. I am talking about the guys in Congress that we all know and love here. I just happen to believe that they are completely wrong. I happen to believe that burning helps the environment. I have billions of years of evolution on my side. What do lawmakers offer us, carbon credits? Fires have naturally (organically) been burning on this planet since time began and I wager that they have played an enormous roll in whom and what we all are. I hope that you can accept my right to voice the opposing opinion."
Larry on Saturday 19 November 2011
"Please forgive me but I have one more point for the opposing side which is; heating limestone to produce lime is a very intensive, energy consuming process. You may wish to Google “carbon footprint for producing lime” As do you, I also care deeply for preserving our environment."
Larry on Saturday 19 November 2011
"This is the best article I've ever seen on this subject - there's actually science behind it! Many thanks. "
Judith Carter on Sunday 20 November 2011
"We use lots of different wood in our log burner, including old fence panels that have been treated with wood stain or painted. Would the ash from this sort of thing be a bad idea to use on the garden?"
Daniel on Monday 21 November 2011
"Just following up on the coal ash matter, you might be interested in the spirited discussion at Regarding BBQ charcoal, it's generally felt that if you're using pure charcoal, then it's fine to use the ash. A lot of briquettes have additivies which may not be desirable to add to the garden. The same goes for treated wood. "
Helen Gazeley on Monday 21 November 2011
"Some good tips thank you"
nathan on Tuesday 22 November 2011
"Daniel,personally I would dispose of any ash you get from your log burner containing paint varnish etc anywhere you can (legally) but not on your veg plot.All sorts of chemicals and nasties in these. As for using ash,what about soot from domestic wood and coal fire chimney's ? My Grandad used to dig in soot and coal dust along with manure on his garden in South Wales ( there used to be tons of it lying around when the pits were operating)saying that it was a natural product and it never done his garden any harm.His adage was "God gave us the earth to grow our food and you must replace the goodness that veg takes out the earth"..I grow on clay soil in West Sussex (UK),last year I dug in some soot and it has already improved the soil where I grew potatoes.I know that digging potatoes up helps to break down the soil but compared to two years ago it has improved the texture of the soil.So I will be digging in some more soot on the plot this year.As my friend Gordon,(82 years young!)who has been on our allotment site for 26 years told me "dig it in "boy" (I'm 62 !),it won't do any harm it's a natural by product".."
melboy on Tuesday 20 December 2011
"Not sure if this discussion is ongoing.But I need to add lime to one part of my property and gypsum to another as well as salt. But I have a high potassium level. Can I then use wood ash from wood burner instead of lime? How much ash? (1 acre). Grateful for any comments. Graham New Zealand"
Graham on Monday 7 May 2012
"Hi, Graham. If you've already got a high potassium content, you need to be wary of adding more potassium, as it can affect plants' take-up of other nutrients. "
Helen Gazeley on Monday 7 May 2012
" got 1 acre to grow veggies ?? ! boy how lucky are you !? I thought I was content with my 250 sq metres ! Completely jealous now ! As Helen says you need to be wary about adding more potassium to your soil,would suggest you do a soil test first. Good Luck with your ONE ACRE !"
melboy on Monday 7 May 2012
"I have an occasional bonfire in an old oil drum, and as you say it should be dry, but this seems impossible for me as it is essential to only move the ash when cold, therefore in leaving it for a few days inevatable it rains and all I have is grey sludge which it seems I cant use. There is no way that I can cover the top of the oil drum as obviously a wood cover could catch fire and there is no metal covers large enough to fit over an oil drum. Any ideas please Joyce "
Joyce on Tuesday 7 August 2012
"Joyce, I use an incinerator. When I burn stuff in the evening, I certainly find the incinerator is cold by the next morning. Does your oil drum take several days before it's cool enough to handle? It's no problem if the ashes are still a bit warm when you transfer them to another container until you need them. Or you could put them straight into the compost bin. "
Helen Gazeley on Wednesday 8 August 2012
"If you use wood heat indoors, this is a good article, if not please consider burying your waste branches, old logs, brush, leaves etc. covering with straw and soil and plantign a garden over top. This is a much more planet freindly approach than burning. It also reduces need for water as the biomass is a moisture sink.."
Tom M on Friday 7 September 2012
"@ Tom...good points you make...but how long do leave the ground before planting up ? i mean how long to leave it so it settles and doesn't burying all this wood deplete the soil of nitrogen as it rots down ?? Just wondering.."
melboy24 on Friday 7 September 2012
"@melboy24..this technique is related to sheet composting and in Permaculture is referred to as hugelkulture.In my limited but wildly successful experience( raised beds bone dry..built up bed thriving)i planted immediately after building the hugel..there is considerable soil over top of the biomass and as it breaks down it offers nutrients to the plant. I have not fertilized the hugel AND PRODUCTION IS HIGH."
Tom M on Friday 7 September 2012
"@ Tom, Thanks Tom thats very interesting..must try and find out more about this..."
melboy24 on Saturday 8 September 2012
"I stopped reading at "global warming"...what a shame."
Jen on Sunday 11 November 2012
"What about ash from my pellet stove? same as wood ash? Can I use it in the garden or around flowers and bushes?"
Pete on Friday 30 November 2012
"If the pellets are pure wood with no addatives to hold them together the ash would be the same as ash from a wood stove. The type of wood used in making the pellets will affect the quality of the ash. Hardwood ash is better than softwood or coniferous ash. "
Bill on Wednesday 2 January 2013
"I am happy to have found this discussion! We burn wood in the fireplace throughout the winter. I live in an area known for its heavy clay (alkaline) soil. I mulch heavily with pine needles and amend soil when planting to enhance acidity. I also compost veggie/fruit scraps and garden debris - with great success. I've avoided using the fireplace ashes specifically related to my need for acidity soil (hosts, azaleas, ferns, etc.) So is there a use for these ashes that will work for me? I must admit that I feel guilty about throwing them out."
Louise on Sunday 6 January 2013
"You could sprinkle them on your lawn. The alcalinity can be neutralized by using sulfur as well. "
Bill on Sunday 6 January 2013
"I could sprinkle them on my lawn - but I failed to mention that I don't have a lawn. My little piece of property is all trees, ground cover, and my garden. I could check with my neighbors."
Louise on Monday 7 January 2013
"Here are 10 things you can do with ash. Or just Google it.,,1581470,00.html Again, burning your tree branches is carbon neutral. As things grow, they capture carbon. When you burn them you are simply putting it back. Why is this so incredibly hard to understand? Everything else you here on this subject is about and for, big money carbon credits for giant, greedy, power hungry corporations....Sure, burying your branches would be lovely, that is providing you have big expensive earth moving equipment in order to accomplish the task."
Larry on Monday 7 January 2013
"Hi Larry...I do not use any earth moving equipment and am quite successful at burying excess branches leaves an decaying logs. Yes it is slow, tough work,but there is no schedule to meet. For small scale gardens, with the occasional work bee and help of friends, the results have been remarkable, and I will check out the link provided, but the common held view is that there is too much carbon in the air and it is better left inthe ground. The fact that it can ffed our gardens is a bonus."
tom on Monday 7 January 2013
"Hi Tom, I live on 2 acres and my yard annually produces a large, unsightly debris pile on average 6' by 12' wide. I won't use a chainsaw and sometimes branches are as much as 20 feet long, sticking out all over the place. I would need a large expensive shredder or a backhoe or both to solve my problem. No thank you, I am poor and just one match solves the problem. It's just like a natural lightning strike from mother nature. Again, the CO2 footprint is NEUTRAL! Please understand that trees take CO2 in and we burn the exact same CO2 out. It is a short 50-100 year, neutral cycle. It is a natural, NEUTRAL cycle. On the other hand, man digging massive open quarries then incinerating the rock while releasing massive amounts of CO2 which has been trapped for many millions of years in order to produce lime and other things is the problem. Corporations are NOT neutral, they are negative. We gardeners are NEUTRAL, just like nature. Think outside of the corporate box and you will see. By the way, I absolutely agree with you on the benefits of hugelkulture providing that you are lucky enough to have an energy efficient way to accomplish it. I found a landscaper that delivered a load of chips for free 2 years ago and I had fabulous results this past year. To settle the debate, I would like to concede that your way, if you can accomplish it, is even better because it falls on the plus side of the CO2 meter which reads; (Positive - Neutral - Negative) We cool? I would love to know if I got through on the NEUTRAL position. Neutral is good and I think that corporations have brainwashed everyone into thinking it is not. I don't know but I feel that I am the only one awake and seeing the truth on this. I think, with the exception of man, every living thing on this planet is CO2 neutral. It's a good thing to just be neutral. "
Larry on Monday 7 January 2013
"One last thing... To be perfectly clear, CO2 is not drawn up out of the ground by trees and then released when they are burned. The CO2 in the ground, stays in the ground under your trees. Vegetation extracts CO2 molecules out of the air not the ground as it grows. It simply gets put back out there when plants are burned....a neutral cycle."
Larry on Monday 7 January 2013
"Thanks for the replies"
Louise on Monday 7 January 2013
"It is good to the society no need of buying wood 4r the market it there for us to use and make our potash and sale."
hajji mohammed on Tuesday 8 January 2013
"Louise, I have had problems with Pine needles. Yes, they are acidifying, but apparently they also release a growth inhibiting chemical. I seldom see much growing under Pine trees in the forest. I nearly wiped out a lovely Raspberry patch using Pine needles as mulch. " on Tuesday 29 January 2013
"GarthWunsch - thank you for this information. I did not know this and will have to look into it. Our soil is SO alkaline and the needles over time have really made a difference in converting the heavy clay soil to a more gardening-friendly dirt. Hmmm - maybe that is why some of the growth on my hostas has slowed..."
Louise on Friday 1 February 2013
"Louise, if you can get your hands on some calcium rich rock phosphate, you be able to cure your ills. It sounds a bit counter-intuitive, but this stuff conditions soil so it can do what healthy soil is supposed to do... feed plants. Is your ph greater than 7.5? Have a look at this website. Fortunately for me and my acid soil, this SRC is mined about fifty miles from my home and this year it is being made available to the home gardener. YEAH! I met the company rep at a gardening lecture. If you think it will be useful, contact john Caron at and he can give you good advice. Tell him I sent you :-) He is an organic farmer and Director with this company."
Garth Wunsch on Saturday 2 February 2013
Louise on Saturday 2 February 2013
"Would adding small amount of wood ash(mostly hardwood)to outdoor tomato/cucumber plant soil mixture be benificial?"
Tony Morgans on Friday 1 March 2013
"Hi, Tony. I'd save it to sprinkle it on the soil when the first fruits start to set. Some people add a touch of potash to the potting compost but I've read that it can rush the plants into flower too quickly, so that they don't build up their leaves enough. "
Helen on Friday 1 March 2013
"On the subject of collecting wood ash from bonfires, and keeping it dry, I use an old metal tool box which used to contain a socket set. The two halves are connected by hinges so that it opens like a book. I lay it on the ground and build a small bonfire over it. The ashes and charcoal fall onto it and once the bonfire has died I can close up the box and keep it dry until I’m ready to sieve out the charcoal. I don’t lose ashes onto the ground where they get damp. As an added benefit, if you have your bonfire late in the afternoon, on a winters day, and close the box when it is hot, and still has a high charcoal content, it becomes a heater which I lift carefully into my greenhouse to keep the frost at bay overnight. It takes hours to cool and I still have a box full of cold, dry ashes in the morning."
Andrew on Tuesday 5 March 2013
"I have a landscape supply yard behind me I have a mill that burn lots of tree shavings.they produce roughly 9cm3 of ash a day I was wondering if I could incorporate it into my top soil as a boosting agent .Will this affect new grass seed being planted in the soil? and I have a good organic compost here I mix with the screened soil as a garden mix I do a 50 50 blend and sell it by the cubic meter would it be beneficial to add ash to this mix and at what rate cheers Dave "
David Fields on Wednesday 6 March 2013
"Dave, there is no simple formula. You need to know the ph and potassium content of your soil mix, then find out how much ash you can add to take it to the desired levels. Generally wood ash is beneficial if it has no chemicals in it from treated wood, etc., but you can put too much. You will have to get a soil test done from a local company or university etc. You might enjoy my blog called Lively Dirt - the Garden Blog at"
Garth Wunsch on Wednesday 6 March 2013
"thanks and I will check out your site"
dave on Wednesday 6 March 2013
"I have a wood stove that produces more ash than I can use. It is 100% oak ash. I did not see much talk about using it on the LAWN. I am most interested in how much to use. I struggle every year with moss under dense shade. I have tried lime, wood ash and moss control and reseeding. Have decided to accept defeat."
George on Sunday 17 March 2013
"How much ash should i add to two cubic yard of top soil"
Cynnthia Coulston on Friday 5 April 2013
"Cynnthia, it sounds as if you're trying to mix in ash to a large amount of soil before you spread it. It would be better to use the soil and then spread the ash where it's needed. "
Helen on Saturday 6 April 2013
"wood ash is directly applied to construction purpose (or)any tests are available in wood ash concrete."
MARI SELVI.M on Thursday 11 April 2013
"I find your connection with pine needles and raspberries rather surprising. I live in Sweden and am surrounded by forest. 95% coniferous. Around the edges of the trees and under the first 20 yards, grow another forest of wild raspberries. That must have a huge amount of pine needle droppings all the time.and I can only call them an invasive weed. They produce prodigious amounts of very good fruit about half the size of commercial. Perhaps they are used to it. Or a strain that is a little different , but look and taste the same."
Geoff Gwyther on Saturday 13 April 2013
"can I plant my cukes,peppers tomatos over a spot that I burned on in the early spring? I am desperate to get my gardern going "
Rose Murphy on Sunday 9 June 2013
"Yes, Rose, you can plant there. No problem. "
Helen on Monday 10 June 2013
"I thought this was so interesting, thank you for sharing all ur knowledge.... I never heard of this till now and I burn a lot of fires with hard wood... I have a pear tree and a peach tree... I'm sure they are going to be very happy to get some ash now and then. Lol. Thanks again. "
marianne heffner on Wednesday 21 August 2013
"Hello There. I discovered your weblog using msn. This is an extremely well written article. I'll make sure to bookmark it and come back to read extra of your helpful info. Thank you for the post. I will definitely comeback."
Herrmann on Wednesday 25 September 2013
"Very Good Idea I Like It"
ilmanvaihtokanavien puhdistus on Wednesday 9 October 2013
"As I was told by my Mother -In law now (85 years young) who advised me - whenever planting ; after digging the Hole - please some dry grass into the hole with some potash - then place the seed in to the hole: some of the Pumkins harvested were + - 18 kgs and Sweet potatoes + - 5 kgs:"
Vivian Ramawtar on Saturday 8 February 2014
" I have three garden plots totaling about 1200 square feet. All organic. We burn 2-3 cords in the wood stove every year, almost exclusively green ash and a little hickory and oak. Throughout the winter the ash gets spread over the snow covered gardens. We move chicken tractors around over that. The combination of manure and ash rots into the garden well by mid spring when we spread compost and plant. Dry summer ashes from bonfires are spread on the asparagus beds and lawn and tossed into the chickens' dust bath boxes. We use the same bonfire pit continuously. It gets sludgy when it rains but a new fire dries it out quite well enough to sift out the charcoal periodically. I've heard that mixing ash with a manure pile while it's composting will release nitrogen undesirably. I normaly dust manure with ash only as I'm spreading it in a garden plot. I'm still considering spreading ash on the dung that our pasture raised pigs leave in the field. I'm supposing that would improve the lightly wooded pasture."
Micheal on Tuesday 25 March 2014
"Personally, I mix my hardwood ash with vegetable scraps I collect in a Rubbermaid trashcan throughout the year (far from house it smells). All the leaf litter, lawn clippings, pulled weeds, and fallen limbs go into a big pile and 2-3 times a year I dump that funky fermented sludge into the pile. Let that sit 2 years turning occasionally and add it to the top of the raised beds and rows of veg garden. It if like black gold and is an environmentally friendly totally organic soil amendment! As far as a post I read earlier about burning natural debris being so bad for the environment.. There are dozens of species of plants that require forest fires for proper seed germination and propagation.. This would indicate to me that it is part of the natural cycle.. just saying"
merlin on Tuesday 12 August 2014
"Hi, I'm doing a science experiment based on the effects of potash on gardening and was wondering where you got your information. I didn't see any sort of bibliography so if you could send me links of your sources that would be very helpful!"
Ellie on Monday 1 September 2014
"We add wood ashes in compost to make the elements more "
Nonar on Friday 12 December 2014
"Thank goodness I found this site! My husband and I are becoming more interested in growing vegetables and fruits as we have more free time. In the last few years, gardening has become a real delight for us. Thanks to all of you for your passion and care in relaying your knowledge and experiences. I can't wait to see that little garden in all the stages of growth and harvest this year! What a blessing it is."
Jocelyn on Friday 3 April 2015
"Hi Jocelyn. Congratulations on getting the gardening bug! There's nothing - absolutely nothing - more satisfying than harvesting your own fruit and vegetables. Good luck with your growing this year!"
Ben Vanheems on Sunday 5 April 2015
"Thank you very much for all the information shred above, very useful! What about pine cones and other tree debis? Can the ashes from burning those work as well?"
louise on Friday 8 May 2015
"Dear all and especially Larry - I'm a UK gardener and a keen environmentalist. Here in the UK we have a system of tolerance towards our neighbours (in theory) and have a legislative system to support that. Bonfires are actively discourage by most councils in this country because they can cause quite insufferable nuisance to others, and if that happens, councils can take action. Lets face it, there's little that is more effective at spoiling a nice sunny day (something to be properly relished in this green and pleasant land!) than a smelly bonfire. I therefore advise caution for those who are yet to be turned to the dark side. And yes - most gardeners have many non-recyclable waste piles that appear around the garden. They can't be put through the shredder or disposed of via composting, but I do wish to point out that burning damp or green material in such an uncontrolled manner produces products of incomplete combustion and a host of other by products, (some if this is the black stuff you see when you light your fire). This contaminated air IS air pollution, like it or not, and this release of very fine particulate is now known to cause quite significant impacts on health for all, especially children and vulnerable others. So yes you can argue that we have always had fires, that human beings are meant to scorch the earth - even nature does it in such extremes that we consider our contributions insignificance but is that really the point ?. Do we want to add to poor air quality or do we want our gardening have a positive influence on the local environment?"
Mand on Saturday 9 May 2015
"I hope we aren't going to continue down this rabbits hole any farther. This thread is not "are burners good or burners are bad". It is Using Wood Ash in the Vegetable Garden. Please let's keep it useful! "
Bill in Peterborough Canada on Sunday 10 May 2015
"Hi Louise. You can use the ash from pine cones and other tree debris too. "
Ben Vanheems on Monday 11 May 2015
"Hi Mand. I too am passionate about the environment and the unecessary burning of plant matter that could be composted. The article is primarily aimed at those gardeners burning wood within wood burners to heat their homes. I produce a fair amount of ash this way, so it's good to know that as well as displacing gas to heat my home by using local wood from tree surgeons, I am also able to use the waste product (ash) in the garden to return some goodness back into the soil."
Ben Vanheems on Monday 11 May 2015
"I have read that adding a ring of wood ash around tomatoes and peppers deters cutworms from destroying tender transplants. Now my husband is wondering if water, draining through the ash, creates lye that will destroy the plants. I'll admit I have had trouble with tomatoes in the past and wonder if the ash is part of the problem. "
Sherman Fracher on Wednesday 13 May 2015
"I like to shred my personal mail / documents when no longer required. Would old paperwork burnt to ashes work the same as burning wood to make potash please?"
Rachel on Thursday 28 May 2015
"You can't be sure with old paperwork that some chemical aren't involved. I would not use this on veggies for consumption."
Bill in Peterborough Canada on Thursday 28 May 2015
"This is really important for veggies like Asparagus who really need the potatssium to grow!"
Kathy on Tuesday 2 June 2015
"Where I live the town collects brush and leaves. Unfortunately they only do this for part of the year so if you accumulate branches from trees you will receive a summons for storing them until collection begins again. This leaves us no other option but to burn them in the fire bowl. I have been using them in the garden for the past two years. I have not heard of having fires to burn being unfriendly to the environment, unless it is treated wood or painted."
Laura on Saturday 13 June 2015
"I think I have looked all through this blog (and it's really interesting) but I don't think it tells me how good potash is for brassicas, turnips and chard/spinach. Advice please? (I have LOADS of ash from my hardwood-burning open fire)"
Sue on Tuesday 30 June 2015
"Hi Sue. Brassicas tend to prefer a soil that is slightly alkaline, so applying wood ash to the ground should help to raise the pH of your soil for these crops if your soil isn't already alkaline. I would also suggest that the same rules apply for turnips as they do for other root crops. Leafy crops such as spinach/chard will benefit less from the potassium content of the ash, as these plants need more nitrogen than potassium to encourage luscious leaf growth."
Ben Vanheems on Thursday 2 July 2015
"Thanks Ben. That helps"
Sue on Thursday 2 July 2015
"And can I ask about comfrey: does that mainly produce nitrogen? I'd really like to know which veggies like which elements (nitrogen, potassium, phosphate), and which of these are prevalent in which easily home-produced fertilisers like comfrey juice, compost juice, wood ash, nettlejuice, rabbit and sheep poo.... not many questions here, are there. Or just point me to a website. This is the most helpful one I have found so far."
Sue on Thursday 2 July 2015
"Hi Sue. The following articles from our GrowBlog should prove useful: "
Ben Vanheems on Tuesday 14 July 2015
"What about the ashes from a fire pit, the duraflame ashes, left over from the fire pit, does that help the garden?"
Janet on Friday 6 May 2016
"Hi Janet. It's really just wood ash you should use in the garden. I'm not sure what Duraflame logs are made from, so it is probably best to avoid adding the ash from these to the garden. "
Ben Vanheems on Monday 9 May 2016
"I can grow anything in the area I burned a huge pile of trees from When I built my house I have planted dead rose bushes and they come to life "
Denny on Monday 16 May 2016
"Thanks for the article. Had to chuckle at "global warming"... we were all supposed to be underwater by now. And considering the amount of smoke and ash produced by a forest fire absolutely dwarfs what any backyard fire pit would produce... lol . ;)"
PrepperSoft on Wednesday 31 October 2018
"Yes, a bonfire is burning materials from the garden that have sucked up carbon, so it's arguably simply returning the carbon to the atmosphere that it had locked up, so no net increase if your garden trees/shrubs keep on growing to suck up more carbon!"
Ben Vanheems on Wednesday 31 October 2018
"Hello, I've heard it said that sulfur is burnt off when wood is burning. Is it this that causes the wood ash to be alkaline? And would adding sulfur reduce the pH? And another question: Do you think adding wood ash is ok if you have already applied nettle and comfrey tea? Thanks."
Mr Luke Jones on Saturday 13 April 2019
"Hi Mr Jones. I'm not sure about sulfur being burnt off or not, so hopefully someone else will be able to answer that part of your question. As for adding wood ash where you have previously supplied nettle and comfrey tea, I think that in small doses, it should be fine to add wood ash, as any tea will have long been used up. I wouldn't use large quantities of both tea and ash at the same time though, but following on from each other after time has passed should do no harm."
Ben Vanheems on Monday 22 April 2019
"Is wood ash good for Hosta? "
Sandra Grubb on Tuesday 25 February 2020
"Hi Sandra. Bearing in mind all the precautions mentioned in the article, a little wood around your hostas once they are actively growing in spring should do them no harm and may well encourage them to produce their flowers. Avoid getting the ash on the leaves though."
Ben Vanheems on Wednesday 26 February 2020
"I have found this forum to be educational, informative, and humorous. My grandparents, my parents and I put ashes form a wood burning stove in the garden. I think its great when something like gardening catches the interests of even my kids who at times spend to much time on Video games. So to have a bi product of heating your house benefit your ability to provide food is I think pretty cool. As for naysayers on burning wood, the bi products of incomplete combustion have allowed us to smoke meat, smoking produces pellicle a protective layer formed by smoke dehydration that resists bacterial growth. I myself like jerky a lot. Gasification, incompletely combusting wood or coal to produce flammable gasses (CO and H2) that can be used as a fuel. So these horrible bi products are being used to better our lives...yeah that sounds pretty bad to me too. The only time fire burns at 100% combustion it is indicated by a blue flame... anyone? So the argument continues. I have 2 points and then I am off my soap box and my $0.02 will have been well spent. If your gardening and enjoying yourself and not lets say, putting moth balls in the ground then go for it. Maybe we should get riled up about The Agricultural Adjustment Act (AAA) a United States federal law of the New Deal era designed to boost agricultural prices by reducing surpluses. The government bought livestock for slaughter and paid farmers subsidies not to plant on part of their land. Surplus, and I thought people were starving, my bad. We definitely need to drive prices up. That's my gardening point. Global warming... I might be wrong but weren't there a whole bunch of movies about an Ice age like starting in about 2002? Again my memory isn't what it used to be, but I think I remember talk of us going through another Ice Age, or was it a plague, or volcanic eruptions with earth quakes, hmm now its global warming. Funny you look up this occurrence, because it is real. It's basically defined as a change in the atmosphere, (happens everyday I thought). I know when global warming can be best pinpointed... you guessed it after the Ice Age. Ok, ok, let me just leave with this thought. I hope this was entertaining, and we are guaranteed 2 things in life. You will be born, you will die. It's how you live in between: follow the Golden Rule and pay it forward (which is the golden rule???). Also anyone in Boise Idaho that has a rhubarb start I could get, purchase, whatever needs to happen, for next year that would be great!!"
Treana aka amazon goddess on Tuesday 13 October 2020
"Many thanks for your thoughts there Treana. We live in interesting times I think, but we can be safe in the knowledge that no matter what you view (on just about anything!), gardening is a wholesome and meaningful activity - and everyone loves fresh, nutritious food! I hope you manage to find some rhubarb. I planted some in the spring and it has established well - looking forward to my first harvest next year. I hope you get to enjoy some too."
Ben Vanheems on Tuesday 13 October 2020
"Please please advise folks to NOT take the ashes directly from their fire into the compost heap of bin. It is a serious fire hazrd. Wet them completely to ensure no cinders remain."
Louise on Tuesday 17 November 2020
"Hi Louise. Yes, absolutely. It goes without saying that ashes should be stone-cold before adding to the compost heap. I clean my fireplace out BEFORE lighting it. This way the ashes are completely cold. "
Ben Vanheems on Wednesday 18 November 2020
"Hi Everyone. I have an extremely small garden - basically a tiny lawn surrounded by plants in containers. I have so far successfully grown dwarf beans and tomatoes, but have had no success with radishes and limited success with onions. Would the ash of hard charcoal from my Weber kettle or wood ash from my ordinary BBQ be effective in container gardening? Your advice would be highly appreciated."
Michael J. Higgs on Thursday 31 December 2020
"Hi Michael. Ash from wood or lumpwood charcoal is fine to use in the garden. Ash from briquettes or charcoal treated with fire starter is best avoided in the garden. Charcoal ash may be used with onions - it helps to deter root maggots, but in containers that is unlikely to be a problem. My preference would be to add it in thin layers to the compost bin. The potting mixes you use in your container garden are likely to have the right pH for most vegetables, and you'd be better off applying a liquid feed or slow-release fertiliser for most vegetables once the initial nutrition in the potting mix is spent. Make sure your onions and radishes get plenty of direct sunshine, and be sure to have them properly spaced. Water often to help both swell in size."
Ben Vanheems on Monday 4 January 2021
"My wood ash from last year turned brown. Can I still use it"
Mary Bowers on Friday 30 April 2021
"for my tomatoes..."
Mary Bowers on Friday 30 April 2021
"Yes, assuming the ash is just from burning untreated wood and nothing else, it should be fine to use."
Ben Vanheems on Tuesday 4 May 2021
"I just save fireplace ashes; mostly oak; some hickory, maple, etc. I have three south-facing raised beds against the side of my house. The clay soil of Ga. is acidic, so PH of ashes isn't a problem. I deep-bury wheelbarrow loads of non-composted oak and beech leaves, dried grass clippings, and work in organic material like peat moss, more dried grass clippings, ground pine bark, etc. and use very little fertilizer. Plants don't need as much nitrogen as amateur gardeners use. I've got some new cages for tomato and pepper plants to use this year, as even the pepper plants have gotten 6 feet tall. It's when I added ashes [minerals] that they got so large."
David on Tuesday 4 May 2021
" Six feet tall peppers David? That is genuinely remarkable! Clearly the ashes are having the desired effect!"
Ben Vanheems on Wednesday 5 May 2021

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