Hello again pcventures and thank you for your question.
What you are smelling (among other things) is Geosmin, and Butyric acid.
"To work in a garden is to understand that it is just fine to take
your pleasures where you find them. For example, on the first warm
spring days, my friends know to expect an early morning call from me
exhorting, ?Go outside and take a deep breath!? I rave yearly about
the first fragrant scent of geosmin, that quintessential smell of
spring, which is actually an odor produced by actively working tiny
actinomycetes in the warming soil. To me, it is a signal that the soil
is awakening and the grand growing cycle is about to begin again."
"Question and Answer on "The Smell of Spring"
I had a natural history question that might fall in your area of
expertise. In very late winter and very early spring, as soon as the
ground is thawed for an appreciable amount of time, there is in the
air a sour, earthy smell. It seems to vanish as the season progresses.
After accounting for other possibilities (not the paper mill, not the
spreading of manure by the U.Maine Farm, etc.) this seems to be an
annual phenomenon caused by Nature. Also, it seems I remember this in
Connecticut, too. My guess is that it is due to soil microbes that can
flourish at these low temperatures, until the temperature rises and
others crowd them. Do you know if I am on the right track?
Frank Wihbey, Maine Nature News
You are definitely on the right track. There are hundreds of
odorant-type chemicals that are released by the microbes of the soil
and litter when microbial activity increases in the spring. Butyric
acid is one of the odor-compounds that can be produced. This is an
unpleasant pseudoseptic tank smell that can emanate from wet soils.
The common "earthy" smell of garden soil and the smell of spring is
usually due to a compound called geosmin.
Jon Connolly, U.Maine Plant Biology and Pathology Department"
"Ann Kennedy hands me a petri dish that an assistant has just brought
into the room. I lift the lid. What greets my nose is a dark, familiar
smell of earth, rich and dank and ripe. The smell brings back warm
spring evenings and freshly plowed midwestern soil.
This is the smell of healthy soil?it can actually be traced to a
compound, geosmin, produced by the crusty little globs in the petri
dish of actinomycetes. Actinomycetes are microorganisms that are a
sort of transitional group between bacteria and fungi. Like fungi,
they produce tendril-like hyphae. But they also have cell walls, like
Thank you for your question, and if you need any clarification of my
answer, do not hesitate to ask prior to rating my answer.
Very best regards
Search strategy included:
"spring smell" acid