When is the best time to use corn gluten meal on the lawn in zone 3.Thank you,wormbin.

When forsythia is in bloom. It works for all zones.

Cat

I'm not sure about zone 3 specifically, but the best time to use it is when you first fertilize. Corn Glutten is a pre-emergent and has no effect on an already germinated weed seed. I'm in zone 8 and I apply it right after the last frost. If you apply it too early and you green up the lawn or plants before the last frost they wont like you very much.

Thanks folks,I have not been able to find a Forsythia for zone 3,only for zones 5-9,I was planning to grow this plant so that I would have some indication as to when to fertilize with Corn gluten meal.Is there anything else I can use to go by? Thank you .
wormbin.

This is the first year for blooms on my new Z4 hardy forsythia...
it bloomed with the Amelanchiers.
Check around for these plants, they should be around in Z3.
aka: shadblow, juneberry, saskatoons
they can be shrubs or trees

Thanks folks,you have all been very helpful,and now I have a better understanding, as to when to use CGM.
wormbin.