last killing frost造句

Sow seeds indoors in potting soil six weeks before the average date of your last killing frost.
The last killing frost usually is in later April, but freezing temperatures have occurred in May.
The first seeds go into the ground about a week before the average date of the last killing frost, in the middle of May in the Hudson Valley, where I live, or when emerging oak leaves are about the size of mouse ears ( conventional garden wisdom that I do follow ) anywhere.
It's difficult to find last killing frost in a sentence. 用last killing frost造句挺难的