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.