Many fruit trees need a certain period of winter chill to enable them to produce fruit in the summertime. But others, like citrus, can be killed by long exposure to low temperatures. If you want to grow lemons, oranges, limes, tangerines or other citrus, and you live in an area where winter temperatures dip below 32 degrees Fahrenheit, stay informed about the weather forecast and take measures to protect your prize trees from getting nipped by Jack Frost.
Building a Frost Frame
Measure the estimated height and width your tree will attain when it is mature because your frost frame can survive many seasons and can provide protection for the tree when it is larger.
Calculate how much wood to purchase. If your tree will grow to 6 feet tall and 4 feet across, buy enough 2-by-2's to form a square 6 feet tall and 4 feet wide. Four corner posts will equal 24 feet of lumber, and eight vertical support posts will equal 32 feet, for a total of 56 feet of uncut 2-by-2's.
Cut the 2-by-2's to their needed length. For this example, cut 4-by-6 foot pieces and eight, 4-foot pieces.
Nail or screw together your 2-by-2's together to form a box, with the four, 6-foot pieces as corner posts, four of the 4-foot pieces at the top and four of them in the center of the 6-foot corner posts.
Cut heavy clear plastic large enough to completely cover your frost frame, and then staple it onto the top and sides, leaving the bottom open.
Lower your completed frame over your tree just before your expected first frost and then remove it in the spring after the danger of frost has passed.