As you care for your lemon tree, watch for signs of distress that include a loss of leaf growth. The foliage is one of the best ways to tell whether something is wrong and it lets you know that action needs to be taken. Whether this affliction is a result of bad weather or a vitamin deficiency, perform the necessary checks to troubleshoot your lemon tree and fix the problem(s) so that you can enjoy a bountiful harvest again.
Check the weather to see if temperatures are expected to drop below 30 degrees Fahrenheit. This cold rating prevents a lemon tree from producing leaves and fruit. If you know a frost is coming, hang a covering like a blanket over the top of your tree.
Test your soil for good drainage by digging a hole about 3 to 4 feet deep and then fill it with water. Check back no more than 36 hours later to see if all the water is gone. If not, the standing water is a good indication that the tree is sitting in soggy soil, which is harmful to citrus. If possible, move your tree to a location with better drainage, or add earthworms to your current location as they improve dense soil.
Provide a fertilizer that is rich in nitrogen to ensure that your lemon tree is getting the nutrients it needs to grow. Use a fertilizer specifically labeled for citrus trees, or employ a product that has an NPK (nitrogen, phosphorus, potassium) in a 2-1-1 ratio. Apply the fertilizer by following the specific instructions on the package.
Remove grass and weeds that are closer than 1 foot to the base of your tree. This additional plant life competes for the vitamins that your tree needs.