Avocado Tree

To care for an avocado tree in New England, which is in USDA Hardiness Zone 7 or colder, you must grow it as an indoor plant because avocado trees cannot tolerate freezing temperatures.

Provide Proper Conditions Indoors
Sunlight: Place your tree in a location with 4-6 hours of direct sunlight daily. A south-facing window is a good option. 
Temperature: Ensure the tree is protected from cold and never exposed to freezing temperatures. 

Humidity: 

Avocado trees prefer high humidity, so consider placing a humidifier nearby, especially during the dry winter months. 

Watering:

Water deeply but infrequently, allowing the soil to dry slightly between waterings to prevent root rot.
Fertilizing: Feed the tree with a balanced fertilizer that has a higher percentage of nitrogen.

Pruning:

 Prune the tree when it's about 12 inches tall, making a cut above the second set of leaves from the top.