the lemon plant is getting big. I transplanted once already to a bigger pot and the plant has been outside all summer, its getting big. My question is: can this plant be left outside in a pot during the winter. Climate zone around 7.
Thank you for contacting the Toronto Master Gardeners with your question.
According to some sources, citrus can be grown outdoors in zone 7 and up (with some protection). However, lemon trees do not tolerate cold snaps well. Temperatures dropping below 29 degrees Fahrenheit contribute to wood and fruit damage, along with dropped leaves.
Although frost is not likely to kill a healthy lemon tree, it can definitely inflict damage, especially if the tree is young, as yours is. They can stand slightly below freezing temperatures for a short time if they have been cold hardened, ie. exposed to less than 68 degrees F for several weeks. Additional protection can be provided by covering the tree with sheets or blankets and adding a string of Christmas lights to add some heat. This additional protection could allow the tree to survive exposure to slightly lower temperatures. For younger trees, it is recommended to bring them indoors before the first frost is expected.
I’ve attached a link to an article on how to take care of lemon trees in the winter.
https://homeguides.sfgate.com/care-lemon-tree-winter-55685.html