Yes and no. It will raise the ph of the soil so if you have acid loving plants this would not be beneficial. It will provide some nutrients such as potassium and calcium but the nitrogen is taken out during the combustion process. Also, laying down too much of it can interfere with the way plant roots uptake nutrients. Better to add it to a compost pile in that it will raise the ph of the pile to a neutral level which is very beneficial to the bacteria therein. You may also give it to a friend who wants to alleviate an acidic soil condition in garden. Of course I am answering this question assuming that you are only burning natural hardwood (not softwoods such as pine) logs or hardwood pellets and not those fabricated fireplace logs which might have harmful combustion byproducts in them. Ash could also be used in pest control for instance if you have a snail or slug problem, lay down some around the plants to deter them. So, I think the most effective place for wood ash is to turn it into your compost pile if you have one.

That is so interesting Loosestrife. The knowledge of people here amazes and fascinates me.

Do not use the ash on your garden if you burn coal of any sort only wood.

Thank you for the advice on ash.
Penybraich

I have to ask, Why not softwood ash? All the potential nasties that pine contains are organic and will be combusted.
On Wartime Kitchen Garden the great Harry Dodson used copius quatities of neat wood ash (high in potash) to feed tomatoes and they cropped brilliantly.

You asked "B" and I will answer. If you read my answer, within it I mentioned that my answer was based upon the burning of natural hardwood logs or pellets and not based upon the burning of softwoods. The reason for this was that I was not familiar with the benefits or detriments of softwoods. You assumed that I said not to burn softwoods when I warned in my next statement not to burn fabricated faux logs in the fireplace since they are not made by mother nature and could have nasty residuals in their ash depending upon who manufactures them. As you see, I try to avoid extending my answers into areas where my knowledge is very limited because that would whittle my reply down to a guess instead of a valid answer. BUT....this is why GOY is Great! We help each other in our answers and in making them more complete as in this instance in that we now know the benefits of softwood ash.

We're very wary of treated woods, some are carcenogenic to burn......

can I ask why you say nitrogen is taken out? as my understanding is nitrogen is unreactive at these temperatures and that's why forest fires add so many nitrates/nitrites to the soil as well as the other trace elements

The nutrient molecule nitrogen is indeed lost in flaming combustion of biomass. It is lost as NO2 and N2O gasses. Sulfer is lost too but that molecule is is not on the plate right now. Tons of nitrogen are lost as a gas from burning trees and soil biomass in large forest fires. Now what you are referring to is that fire tends to increase the short term availability of nitrogen for plant growth by converting inaccessible organic nitrogen into usable inorganic form directly via combustion of organic matter and indirectly creating conditions that speed up the microbial decay process. This is what happens in the combustion of soil biomass. Looking at our good old hard wood log ash though we find that most of the nitrogen in it went up with the combustion process. Now a question for you- Why dont rocks burn?(this is a question once asked of me by my grandson-and I gave him the answer which he understood years later).

if they get hot enough they do ouch!
I read your original as atmospheric N. obviously the nitrogen in organic molecules will react in combustion.

Time is UP! Q: Why don't rocks burn? A: Because they are fully oxidized. That's the answer which I gave my then six year old grandson. He fell silent to my answer with no further request for an explanation of it.....it was years later entering into the magical world of oxidation- reduction reactions where he finally understood my answer to his question. Alas, he never asked me why the sky was blue?

Now my girls did and why water was blue and why why why why why why why why.. on and on. still I love inquisitive minds.
questions now tend to be 'may I borrow?' usually money :o)

Yea, when my wife kept on calling one of my then teenage sons to come out of his bedroom for something, well here's how it went.....Chris.. CHris...CHRis...CHRIs...CHRIS !!!...(nothing)... Then she said...TWENTY DOLLARS!..he charged out of the room like a rhino after a landrover.

ah that tends to sum up teenagers doesn't it. I also heard another overgeneralisation the other week. 'how do you know if a teenager is lying? They are talking to you!'
very unfair and I am sure your lad was already on the move before the money was mentioned ;o)

Whether he was on his way or wasn't ,it was perfect timing. My wife and I laughed ourselves silly when it happened and we would recollect that incident every now and then to ourselves for many years thereafter.