Wood ash is widely used in the east where we have naturally acidic soils. It is alkaline so if you have an alakaline soil, probably not a good idea. Wood ashes average N-P-K value is 0-1-3. It is also a source of Calcium and other micro nutrients. On a 10 x 10 ft area I would maybe put a gallon.

wayne .... a similar question was asked in the compost/soil forum. Some interesting responses. Our CO River water is alkaline, as are our native soils. My wood ashes go in the trash...mostly

Here is a link that might be useful: Wood ash

Same here - alkaline soil. Wood ash can totally ruin a garden if you don't first know what your native soil pH is to begin with. Even in highly acidic soil the recommended application amount is quite small - something like 1 lb. per 200 sq. feet.

In addition to the previous discussion linked by Barb, there are many other discussions on it that a search will pull up for you if interested.

Dave

Dave's number looks low, while Farmerdill's number is closer to my experience. Of course, my native soil is acid (5.5), but in my experience, 20 lbs for 1000sqft is appropriate, again given an acidic soil. NC State's Extension also gives numbers similar to these.

I read that Farmerdilla suggesting a gallon per 100sqr-ft,
David saying 1lb/200 sqr-ft. But withouth knowing th soil
PH those numers may be wrong. Example:
raising soil PH from 5.5 to 6.0 would require 10 times as much ash as
if you had to raise it from 6.5 to 7.0

I have acidic soil.Started probably around PH=6.
So I needed to add lime and ash. Since I burn lots of wood,
I get alot of wood ash and keep adding them to my garden.

As I have heard, wood ash in general has less than half the
potancy of garden lime. But the thing is that dry wood ash
coming out your fireplace is very light weight.
So by weight you cannot get equivalent of 40lbs of garden lime easily.
100% dry wood (0 moisture) will yiels 7 to 10% ash by weight.
But most fire wood have lots of moisture (20 30% if seasoned)
So if you burn a ton of wood(=2000lbs), 30% of it is moisture
So dry weight will be 1400lbs. And 10% of it will be 140lbs.
We are talking about dry ash coming out of fire place, not wetted.(Believe me, this will be huge amount of ash.)
That is equivalent to 70lbs of lime, or less than two bags.

Having juggled all these numbers, my point is that if your
soil PH is under 6.5, and you have 2000 sqr-ft garden, do not wory about over doing it.

We bought a wood stove last year and spread wood ash on the gardens and the lawn. Our native soil is thin and acidic and the wood ash provides immediate benefit. We notice that the grass grows thicker and greener where the ash has been applied.

Hi Chervil, I am about to plant some of the seeds you sent me. Thin and acidic is pretty much what is here too. The beans, the brassica, the betas, the tomatoes all like the ash here.

Had a row of 40yr old Spruce trees at the back of the yard taken down, last winter. I put on a considerable amount of wood ash this past early spring and decided to garden in that space. Friends were amazed by the size and quality of the plants I was growing in a first year, nontilled plot. Corn, Tomatoes, Winter Squash, Zucchini, everything did really well. This year I am having the soil tested to see exactly where I am.

Steve

You don't say where you are in CA, but if you are along the coast, go easy on the ash, perhaps using it only as a top dressing (where it can discourage some bugs too). P is only readily available at pH 6.0-7.5 or it binds to either Al or Ca in most soils. Humic acids derived from the breakdown of organic matter seems the best solution to CA alkaline soils, so mixing the ash with finished compost as a top dressing/mulch is how I would go here in LA.