Otherwise soil temperatures can be raised by drying soils or the use of clear plastic mulches.
If possible, use black plastic mulch on the sweet potato bed.
I could still see a strip of black plastic "mulch" peeping out around the edge where some attempt had been made to suppress the weeds.
And she is devoted to black plastic mulch: six-millimeter-thick polyethylene, to be exact.
Plant size and yield have been superior when grown on plastic mulch as compared to bare soil.
The plastic mulch covering the soil decreases the crusting effect of rain and sunlight.
The soil underneath the plastic mulch stays loose and well aerated.
These non-biodegradable plastic mulches must be removed from the field and disposed of properly.
The recycling of this plastic mulch is the environmental problem.
"The soil surface was about 35 degrees lower in the middle of the day than under plastic mulch," he said.