A: I would suggest you wait until the threat of frost is over. The final date for frost may be sometime between March 15 through April 15. Of all the citrus, limes are the least cold tolerant. Limes may show cold leaf damage when temperatures drop into the low forties. Hard freezes, similar to the ones we experience in 2009, will most likely destroy the whole tree. However, once they are established, which may take five to seven years; they should survive through most of our winters. It would be important to protect the young trees through those vulnerable early years. If the tree is small enough, cover the whole tree when temperatures go below forty. Be prepared to remove the cover when the temperature rises. It would not be beneficial for the plant to stay in darkness for any length of time. Limes and lemons set flower and fruit throughout the year as long as temperatures are warm. They normally have different stages of fruit maturing on the tree. When a freeze occurs, it would be best to remove any fruit. Some people think the young fruit will mature later but it will be destroyed by the cold. I would suggest novice home citrus growers start with a more cold-hardy citrus such Satsuma, Ambersweet orange or Limequat.
Q: Currently I have a lime tree in a pot and I want to plant it outside. When would be a good time?