Air spade/Air knife

KennerTree

Getting one real soon, just looking for some tips/tricks when using this thing. How long does it take to radial trench a large mature tree 36" dbh out to the drip line and amend the soil with compost? Should the soil be moist or saturated? Thanks for any info you can give.

Sean Freeman

Moist through the depth that you intend to excavate is best, not saturated though....very messy. I have found the knife to be pretty quick but the amendment process very slow....make an allowance for that!

No matter what protective gear you wear (though I have not tried a full suit!) you will end up with soil and dust almost everywhere on your person! Make sure you take plenty of breaks, or rotate the operation with another guy, its a bit like operating a jack hammer in that regard, tiring on the fingers and wrists.

KennerTree

Thanks for the reply. Should I irrigate the night before if there hasn't been any rain for a few days? I read somewhere someone recomended a respirator, would one of those paper dust masks be sufficient?

Sean Freeman

The jobs I've done that required irrigation (and yes I have done air knifing in dry horrible compacted stuff...not fun!!!) have been irrigated at least over night...ideally two or three times in the week leading up to the job (but things are never so easy eh?)

If the soil is moist your face shield should provide good proteection but yes the paper masks are good value.