[Kathie]

I have a bin full of wood ash from the wood burner, is it any good for the garden or compost bin?  Thanks

[JayG]

It's a good source of potassium and a little lime, so pretty good for any fruit or flowering vegetable plant, but it is usually fairly alkaline so don't use on blueberries or other ericaceous plants, and it's probably a bit unwise to use on spuds too.

If your soil is poor don't rely on wood ash alone, as it hardly contains any nitrogen or phosphorus (the N and P in "NPK")

[Kathie]

Thanks JayG :happy:

[Aidy]

Potassium is also good for your roots, I use it on me onions and garlic.
http://www.allotment-garden.org/fertilizer/npk-fertilizer.php scroll down to Potassium.

[Taistealaiche]

It's a good source of potassium and a little lime, so pretty good for any fruit or flowering vegetable plant, but it is usually fairly alkaline so don't use on blueberries or other ericaceous plants, and it's probably a bit unwise to use on spuds too.

If your soil is poor don't rely on wood ash alone, as it hardly contains any nitrogen or phosphorus (the N and P in "NPK")

I assume we're talking about untreated wood ash? Or would ash from treated wood be ok?

[JayG]

It depends what it was treated with - wood readily burns "to completion" so any organic nasties (including creosote) shouldn't be present in the ash - heavy metal residues are potentially more of a problem (mainly lead used in paint, although it was banned in the UK in 1992 - don't know about NZ.)

[Taistealaiche]

Lead was also banned in NZ some time back. I haven't a clue what the wood has been treated with as it all came from scavenging

[rowlandwells]

because i burn wood on a wood burning stove in our greenhouse i burn old pallets chip wood basically any old wood that's going including old railway sleepers the greenhouse heater is a hungry beast for wood 

i also have wood ash from the farm from my winter hedge cutting i use the wood ash on my onion plot prior to planting every year i was given that advise from an old gardener years ago

the onions seem to thrive on it i don't know if it would be OK to use on my brassica plot i always sieve the ash before using so its very fine to spread over the garden

 Aidy says it good for root crops so ime going to use it on my root crops never thought of that a good tip Aidy well worth a try

[solway cropper]

It depends what it was treated with - wood readily burns "to completion" so any organic nasties (including creosote) shouldn't be present in the ash - heavy metal residues are potentially more of a problem (mainly lead used in paint, although it was banned in the UK in 1992 - don't know about NZ.)

Some of the older pressure treatments used compounds based on copper, boron, arsenic, etc. so you may find increased concentrations of these in the ash, especially if you have no idea where it came from. I use quite a lot of wood ash round the plot but only ever from untreated wood.