Bulb food
Jane McGary (Wed, 21 Oct 2015 10:50:49 PDT)

Heather asked," So bulb food? Any suggestions? Is pumice a substitute
when planting?"

Pumice is not a fertilizer, but it adds some mineral nutrients,
especially if you can get unwashed pumice including fines (this is hard
to buy even here, where pumice is sold by the cubic yard). It will raise
the pH of acidic soils slightly. When mixed with peat or other very
acidic components, pumice breaks down more quickly than it would
otherwise, and presumably its minerals then are more available to the
plants.

I use white pumice, but Loren Russell of Corvallis, Oregon, a keen
grower, swears by red pumice (locally known as scoria), which I think
has a higher iron content. I haven't seen it in sizes smaller than about
2 cm, and I prefer the smaller size for seed sowing. My new raised bed
for bulbs has a larger, washed size of white pumice, but also local
concrete sand, which has fines of similar mineral content; I also added
some limestone chips and an organic mix. I do apologize to the
scientific gardeners, but I make planting beds much as I cook -- to my
own taste, and using what's available.

Jane McGary
Portland, Oregon, USA