After one of the sunniest Aprils ever here in Wisconsin, we are now
slated for a good week of solid rain and overcast. What I wonder is
how much light still comes through that my plants will be able to make
use of? Obviously, it's not golden sunlight, but do enough of the
wavelengths that stimulate photosynthesis and growth still make their
way through the cloud cover and rain? Or will my plants just sort of
enter semi-dormancy until Mr. Sun pokes his head out again?

viv

In article says...
After one of the sunniest Aprils ever here in Wisconsin, we are now
slated for a good week of solid rain and overcast. What I wonder is
how much light still comes through that my plants will be able to make
use of? Obviously, it's not golden sunlight, but do enough of the
wavelengths that stimulate photosynthesis and growth still make their
way through the cloud cover and rain? Or will my plants just sort of
enter semi-dormancy until Mr. Sun pokes his head out again?

It doesn't really matter since it's still too early and cold for
anything to grow properly. Except for spring flowering perennials,
nothing gets going until the end of May here in Chicago and being in WI
you're probably a half zone lower than here. We're getting the same
storm system and I think the rain does far more to stimulate growth than
a week of low light.

Since I can't be outside building trellises or painting planters the
rain has pushed back my garden infrastructure projects by a few days or
maybe a week.