If I am not mistaken, I have read where that is a definite no no. Something about fly ash. There are others on here who can probably be more specific, or you can do a google search and find a lot of information, I am sure. I would not do it till I had checked it out more, if I were you.
Bill P.

Many people say that briquettes are made with coal and other bad things for the garden. Real charcoal, the expensive stuff, would be fine. Gives the soil a nice dose of potassium. OK, here's where the lesson ends and the story starts. I dumped briquette ashes in the same spot for years right off my deck. My wife planted Hosta there and it's absolutely HUGE. So, in all my wisdom, I planted horseradish right next to the hosta and it too grew huge. The leaves on the horseradish grow to 4 feet tall and almost a foot wide. It's already flowered today and is just growing like mad. Same thing happened last year. Now, all this in rocky gravel dirt, not soil. So-o-o-o, maybe there's nothing wrong with briquette ashes after all. Neat, huh?

Gee, it MUST have been organic charcoal LM...;-)

they should be good

Be aware that ash tends to alter the Ph of the soil towards the alkaline side. If your soil is really acid they might be fine but if you have soil on the high side of 6.5, they are not going to be good for tomatoes.

Charcoal is made from wood, burnt limiting oxygen. Wood ash is good for your soil in limited quantities. It does raise your pH (more alkaline). I use wood ash all the time.

I would only do it with the more expensive "specialty" charcoal. Cheap charcoals are made from sawdust held together with glue. Glue probably would *not* be good for the garden.

I thought that ashes were acidic. In regards to the natural charcoal being expensive, I just buy natural lump charcoal. its just peices of pure wood carbon. Its $3-5 a bag.

Wood ashes contain potash, which is caustic (alkaline). My concern with BBQ briquettes is that the more popular types are often pre-soaked in lighter fluid (and if not, then fluid is often used to get them started) and making sure that whatever ashes are used don't include unburnt pieces that might still contain the lighter fluid residuals not burned off.

Thanks for the responses.

I wish my grandmother was alive today to ask her the secret to her never dying garden. But until I learn more, the ash stays away from my plants. :)

Charcoal briquet ashes: Don't use them. Bunch of non-veggie-friendly stuff in them.

Terra preta, or terra prêta do índio, refers to expanses of very dark soils found in the Amazon Basin, thought to be a product of indigenous soil management dating back as far as 800 BCE. Charcoal may be one of the ingredients added by native Amazonians to their farm plots to achieve the rich, productive soil.

"Terra preta consists of low temperature charcoal, pottery shards, plant residues, animal faeces, fish bones, and perhaps some biological agent like a special ecosystem of healthy microorganisms. As it is very rich in nutrients to this day local farmers and caboclos in Amazonian basin seek it out for use as compost." [ Source = Terra Preta ]

Here's a website that tells what goes into Kingsford brand of briquettes. Nothing sounds that bad to me. The "glue" they use is starch.

Here is a link that might be useful: Kingsford Charcoal Composition

From that same website, the link to the "Match Light" version of Kingsford with the charcoal fluid in it is here.

Here is a link that might be useful: MSDS for Kingsford Match Light (PDF)

OK people I hope you are still on here after this many years!!! Jban23 from RI I noticed you grew hostas and horseradish in an area that charcoal ashes from briquette bbq was dumped. I dug out a whole bunch of my hostas in my yard and going to the lake to plant hostas in an area at the cottage that they've dumped their ashes from the bbq in same spot over the years. I thought ashes were good for plants, and am trying it with hostas. Now I'm scared because I've been on many forums that people adviced against until I saw this one. AND YES its still on google when I searched it up. I want to know if they continued surviving over the years......like I have no choice but to plant them or keep them damp for a week until I return home. Heading out tomorrow morning. I have two areas there I am going to plant hostas, lilies and daylilies. One is just organic area that had an old BBQ huge thing so I am using lots of mulch and maybe put some of the ashes from one area to the other area so one area isn't as concentrated??? Try it for a year and see what happens???? Or replant back into my yard??? HELP ANYBODY OUT THERE on this old thread!!!!!

They've used kingsford lots before and last few years its some kind of wood charcoal. I will check out the link. And thanks for replying back even after all these years. I guess what that first person said is what popped up on google when I searched. I didn't know what kind of a thread it was but I assumed if that one person was able to do it I would ask. Not too many good things are being said about charcoal!! Yikes!!

Michelle

Wood ash is fine and beneficial. But not charcoal made from coal.
I used to burn lots of wood in fireplace and the ashes went into garden.
It is a good source of potassium, among other things, and can raise the pH. Good if your soil is on the acidic side.

Sey

A soil test is recommended before using wood ashes.

Agree with both Sey and Daniel.

"They've used kingsford lots before and last few years its some kind of wood charcoal. I will check out the link."

Unfortunately, even if we were expert recyclers of grill and pit ashes I think you don't have enough information, since you really don't know the current composition of the soil.

The link with the ingredients just included "borax" as part of the formula and "sodium nitrate".

Borax is used for mold release so the briquets look nice and cute without breaking. It also moderates the heat intensity as an insulator so the briquets last longer. Sodium nitrate is the common flammable/explosive product in old style black powder and it is in there to assist in lighting the fire (lol because the borax retards the fire, no surprise)

Borax in tiny pinch quantities is a source of boron, a necessary nutrient for most if not all plants, including tomatoes. It becomes toxic if it accumulates and easily could kill the plants. The sodium nitrate contains sodium which plants likely also use in minute quantities, but in higher amounts it stresses plants. If the ashes have been there a long time, these chemicals can be all leached into the water table and cause aquatic problems too, but leave your ex-pit garden spot cleansed of them.

As far as the coal in the briquets, I'm on Sey's team about not wanting it, no way, but honestly as a science geek I don't think it would kill the plants if you amended the soil. There is a lot blowing around my local park and but gradually in trace amounts ...not a pit BBQ. I don't know and I'm not sure anyone could tell us what heavy metals could be present in the impurities in any lot of coal. That said, you don't eat your hostas but I eat 4 pounds of tomatoes a day when the growing is good.

If in recent years it has been lump charcoal (the Royal Oaks type of stuff I'm thinking without checking) If you build on top I suspect you'd be OK. It is a natural part of the renewal of forest ecosystems that the underbrush gets charred and leaves a layer of soot, and that nurtures the next renewed ecological cycle. So try to be even handed when you read all the scare mongering on the Internet. The uncomfortable part is not knowing specifically what parameters Kingsford worries about saying don't use the ashes as a fertilizer. Otherwise if a lot of rain passed through your old pit in the intervening years I'd actually be encouraging you.

Cheers
PC

The only thing I could possibly do is test the soil, but, since this is cottage life, and simple at that I either won't bother at all...or I'll experiment for the season and see what happens. I've got little bright pink florescent tags I made to locate where these hostas will be in the spring. I won't eat them so I will try and see what happens. If they don't make it next spring I'll know why. This isn't the nicest thing to do. I'm hoping what I read on that one tomatoe thread that somebody planted hostas and horseradish will also happen to me and flourish the plants. If not I remove the survivors and bring them home or relocate to a different spot. I have two spots at the lake I can try this at. Maybe I'll start with the one area that has no charcoal remains there. No I have no idea what the soil is like out there!!

Should I experiment??? I think I will try. AND PC...wow 4 lbs of tomatoes a day?? You must surely like them!!

Michelle

A search in Google.

"Should I experiment??? I think I will try. AND PC...wow 4 lbs of tomatoes a day?? You must surely like them!!"

As I see it ... the experiment is worth it if you'd otherwise not do anything about it.

LOL! Clearly you need to start a few tomato plants and catch the fever! You innocently stepped into Tomato Territory ;-)

I think you should experiment if that piece of land is convenient, I'd want to reclaim it for the moment for ornamentals. The quicker you reclaim it the quicker it will get progressively better. If you leave it fallow you'll just be treating it as a toxic site and postponing it until you don't want to garden anymore, and what fun is that?

I wish you good luck and since you mentioned it has been quite some time, that made me feel better about this. If you can amend it with some nice compost and forest product, to cut the effect in the top 8 inches or so to help that the plants will do fine. If you're squeamish about coal, I thought I'd mention that tar at one time was used to water tight vegetable pots used to grow plants in, for some uses. Hope you like and have time for a little hoeing :-) and that it is decomposed enough that it doesn't raise a powder storm.

Cheers!
PC

My soil is alkaline. Wood ash is, to me, toxic waste. It doesn't go near my soil except in potential superfund sites. If your soil is acidic, go for it.

Never quite sure what is in charcoal. Many briquettes have additives that are put there to stabilize the fire and make lighting easier. Also binders. I would never put charcoal ash in a garden because I'm really not completely sure what toxins I'd be putting there by doing so.

benefits of wood ash in soil [Google search]