Wood Ash for Soil Building

[greenthumbomaha]

In my main garden I have clay soil, and it is highly alkaline.
At the lake I have raised beds very sandy despite additions of black cow and bagged pine chip mulch, still alkaline too.

I scooped up a bucket of wood ash from a burn pile. The pile contained fallen branches from a silver maple but mostly ash trees. Lighter fluid and gas was used to burn the pile.

Ideally I would like to use this as a soil amendment for edibles, but would like advice on its best use. I rarely have natural products available, except for a small amount of leaves. I am always buying and hauling bags.

- Lisa

[Worth1]

It will make it even more alkaline.

[bower]

+1 as Worth said - the ashes will raise your pH even further.

[Nematode]

Wood ash also is not buffered like lime.
It can really send the ph up.

[Labradors2]

AND ash particles can be sharp and harmful to worms!

Wood ash is mostly calcium and carbon, and oxide, I believe. It has potassium, a lesser amount of phosphorous, and trace minerals. Although I've personally used it in soils that were probably already alkaline without issues, I wouldn't recommend it unless you're just experimenting and don't mind increasing the pH. I wouldn't use more than three handfuls per plant or so. Many of the minerals in wood ash are water soluble, and readily available to plants (so, even the trace amounts make a noticeable difference). High pH can cause mineral deficiencies and/or toxicities, however. Reducing the pH with sulfur can take a while.

If your pH is consistently high, I recommend amending with peat moss. It seems to make soil with too much wood ash in it growable (at least for a season or two, if not longer). I'm not sure of the long-term effects of peat moss on pH, but sulfur is usually used to reduce pH, and takes a while.

Growing stuff generally should help to draw calcium from the soil over time. Tomato plants seem to use a fair amount of calcium.

For your clay soil, I'd be a lot more concerned about how much organic matter you have, though. And I'd recommend mulching. Mulching or using black plastic also seems to make some tough soil more growable. Clay soil can insulate well, and stay cool, IMO; so warming it with black plastic may help the plants.

Your sandy soil is alkaline, too? That's interesting.

I wonder if calcium is what's keeping the pH high or if it's other minerals.

[Worth1]

We had a big wood ash pile when I was growing up, the chickens loved it to dust their selves.

I've also found that adding extra nitrogen (I used a combination of ammonium sulfate and urea) helps plants that have too much wood ash.

If you had a big pile of wood ash in a spot (from burning wood in that spot), and move it, you can count on the soil where it was needing some peat moss, nitrogen and/or such, since it seeps into the soil, especially when it rains. I usually spread it around and mix with other soil, though. Although Worth mentioned a pile, too, I was thinking of the pile in the OP.

[bower]

Originally Posted by shule1

I've also found that adding extra nitrogen (I used a combination of ammonium sulfate and urea) helps plants that have too much wood ash.

If you had a big pile of wood ash in a spot, and move it, you can count on the soil where it was needing some peat moss, nitrogen and/or such, since it seeps into the soil, especially when it rains.

Three handfuls per plant sounds like a huge amount to me!
I did not have good results experimenting last year with a much smaller amount of wood ash in my container soil - maybe a small handful over 2 X 3 ft for two tomato plants. Won't do that again. Messing with pH does not help the plants to get their nutrients, including potassium which was the input I hoped for... OTOH, everybody's soil is different, nothing burnt seems at all helpful here.



IMO (at least for my area with acid soil and lots of rain) the best way to deal with a surplus of wood ash is to add it to the compost for the potassium, let the pH issues work themselves out in the organic matter pile before you apply it to plants. This is what I used to do when I burned wood for heat, and the compost ate it up and seemed to be neutral anyway by the time it was done.

[GrowingCoastal]

When I tried a little wood ash in container tomatoes it did not do good things.

[greenthumbomaha]

Oy, I never thought of ashes as haz mat for worms.
I grew up hearing of proudly using fireplace ashes around the garden.

Yes, our water is very high in calcium cabonate. PH is 8.5. My shower doors are impossible to keep clear. Its pretty common to have a water softener, but I never had one installed. Radium is also on the high side. Everything has to adapt to what we have.

I hear a bunch of nays and one "maybe but in moderation and in con★★★★★★★★ with peat". And thank you for the note of caution of container use. That would have been my next question.

The clay worked great for peppers, despite its high ph, but my immediate need is for a looser soil to plant garlic in within the week. It would need a significant amount of amendment, and apparently a handful is not a viable material.
Bummer , bummer, bummer I thought I had some black gold for free,

- Lisa

@GrowingCoastal and Bower Something seems very amiss there if you're using a small amount of wood ash and getting negative results because of it. I guess neither of you literally said the results were negative. Did you mean the results were negative, and significantly so? Or did you just not notice a benefit, and did not want to risk changing the pH because of it not seeming to be worth it?

[GrowingCoastal]

The years I added both lime and ashes I got a lot of white flesh in the tomatoes. The very hot weather must also have played a part in this. Now, I add no ash and no lime. I find that I still need to use water that has been acidified. Tap water is approximately ph7. I use promix with michorryzea and mushroom manure.
Plants did skirt the outer edge of blossom end rot if watering was the slightest bit uneven. To help with that I used some calcium nitrate.

I haven't done my totals yet for this cooler summer but the tomatoes did much better with plants looking good until the end and no pm issues until the very end of the season after I let Esterina dry out a couple of times.
So, no ashes for me.

[bower]

Results of the wood ash were definitely negative for me. Not one of the tomatoes in those containers had sweet fruit, although they are all from sweet tomato lines - siblings in untreated pots were as sweet as ever and beat the taste tests hands down.
I used the wood ash instead of lime, in my case I use lime every year and it seems to be a good thing even in containers, the condition of being watered so often is just like outdoors, there is a tendency for the soil to acidify over time in this climate and needs to be pushed back (we have no calcium in our soil here either).

Now it is a fact that potassium directly affects tomato sweetness, and potassium deficiencies are also the cause of fruit defects as Coastal described - white flesh, uneven ripening. There are a lot of factors that can affect potassium uptake (too much sun, not enough sun, soil temperature too hot or too cold, pH too low or too high.) We know that wood ash is rich in potassium, but is it not accessible to the plants because of the high pH? Seems to me that the amount you'd have to add to gain potassium as a nutrient could also put your pH out of whack - at least, that would explain what happened. Or maybe it's a thing with the peat in container mixes. Maybe potassium gets locked up with the high pH, needs a change of conditions to make it available...

[Nan_PA_6b]

Originally Posted by greenthumbomaha

...my immediate need is for a looser soil to plant garlic in within the week. It would need a significant amount of amendment, and apparently a handful is not a viable material.
Bummer , bummer, bummer I thought I had some black gold for free,

- Lisa

Gather fallen leaves, and/or go around to your neighbors' curbsides the night before trash pickup and snag their bags of leaves. (I've rented a U-Haul to do this. My very embarrassed DH demands we do it after dark.) Spread a thick layer of leaves on top of your garden. Soak with water and lay cardboard (remove all tape) on top with a few rocks to hold the cardboard in place. Let sit all winter, then remove cardboard and plant garlic in the spring. Or plant garlic in pots & transplant in spring. Cardboard, leaves & rocks are free.