What climate are you in? They may germinate, but the sprouts may not survive if you keep them outside and get freezing temperatures.

Martha

Common milkweed typically requires cold stratification in order to germinate, so if it is cold enough, then a month outside may be helpful.

I would question the timing of planting them though--it is quite early for the normal growth cycle of common milkweed.

And like Martha indicated, knowing what zone you are in would help very much!