Soil Safety

Asked September 15, 2020, 11:57 AM EDT

Hi! Because of the wildfires and ash in my garden, should I scrape off the top layer of soil/ash from my garden to remove the ash? Mostly curious about the safety of ash in the garden for future growing.

Marion County Oregon

1 Response

I have no concern whatsoever about my garden beds or my compost piles because of ash.

Ash is a source of readily soluble - and so plant available - phosphorus and potassium. Probably not more than 1-3% of either.

Now, ash also rapidly raises pH, but given that it's only on the surface, that effect is likely minimal. Our winter rainfall pattern tends to lower soil pH over time. Likely you would require inches of ash to really make a difference.

We've been blowing ash off of the vegetable plants and valued house- and ornamental plants with a leaf blower - and the car. Recall that ash + water is the recipe for lye - so if the promised rain really comes - I'm going to blow the ash off the car before it does!