"Peggy" wrote:

Does anyone know if stapling plastic over my zone 5 raised bed would be
effective in starting my mesclun, fava beans and onions earlier than normal
... or will the soil still be too cold?

Make hoops of PVC pipe to hold the plastic.

Apply the plastic, give it a couple of days to warm the soil,
then plant.

keepan eye on the temps ... you can have cooked mesclun easily.

Tsu

--
To doubt everything or to believe everything
are two equally convenient solutions; both
dispense with the necessity of reflection.
- Jules Henri Poincaré