Old blown-in cellulose insulation for hugelkultur?

We are replacing our blown-in with batt insulation during a remodel... can I bury the loose cellulose in my next hugelkultur bed or is it better going to landfill? I can't detect any additives; it feels a lot like lumpy sheep wool, and there's no odor, but there might be some flame retardant treatment on it.

We're in California, if that makes a difference in the requirements of blown-in flame retardant treatments.

Anyone else here burying non-wood things, or rather highly processed wood things in their beds?

Cheers,

JP

Could it be rock wool? It was made with asbestosis for a lot of years.

Much of that stuff had boric acid added as a fire retardant. Now boron is a necessary micronutrient, but usually in wet areas that get a lot of rain. In places like California, it piles up in lake beds and they get 20 mule teams to haul the stuff out to make laundry detergent. So you probably don't have any boron deficiency and adding all that stuff might bump it up to toxic levels. And then you would have to wait for lots and lots of rain to leach it out of your hugelkultur.

I'd say let it go to the landfill.

Bob Anders wrote:Could it be rock wool? It was made with asbestosis for a lot of years.

This was installed in 2010 after a PG&E audit found our dwelling inadequately insulated... pretty sure it isn't asbestos-based.

After spending an hour hunting online, it does seem prudent to not use this insulation in a California hugelkultur bed. Boric acid is indeed the major component of fire retardant treatment of it and as John noted, California (or at least southeastern California) has a bountiful accumulation of boron and not enough rain to make it disperse very quickly.

If I were in the rainy Pacific northwest, I'd have no qualms about building beds and reusing old cellulose insulation.

I'm going to see if our waste and recycling people accept it as compostable or not. As it is, I've decided, "Not in My backyard".

Thank you for your input!

JP