A frost-sensitive, subtropical plant, the avocado tree (Persea americana) grows only in the warm climates of U.S. Department of Agriculture plant hardiness zones 8 through 12, depending on the cultivar. Most avocado varieties can not endure sub-freezing temperatures for long and need to be over-wintered indoors in colder areas, but selecting the right time to bring the tree indoors depends upon several factors. If you reside in an area which gets frosts, plant your avocado in a container so that you can more readily move it for winter.
Variety and Cold-Tolerance
The capability of an avocado to resist cold temperatures depends somewhat on the sort and cultivar. As an instance, that the “Hass” cultivar is frost-sensitive and damaged with temperatures below 32 degrees Fahrenheit, while “Bacon” withstands 30 F. Several varieties are especially cold-tolerant, such as “Zutano,” that can endure 26 F for brief periods and 2 especially frost-hardy cultivars, “Mexicola” and “Stewart,” that are hardy at temperatures as low as 18 F. Due to these differences, planning the ideal time to move a tree indoors depends upon cultivar, though it’s always best to use caution and move the tree indoors a week or two before reduced temperatures arrive in your area. In some areas, you might not have to move the tree indoors at all.
Think About Your Climate
When deciding on the best time to move a avocado tree indoors, in the end, think about the typical first frost date as well as the magnitude of winter cold in your town. As an instance, USDA zone 9 might have occasional periods as low as 20 or 25 degrees Fahrenheit, while an occasional frost in USDA zone 10 may lower temperatures to 30 or 35 degrees F. Even though minimum winter temperatures fluctuate in both of these zones, the first frost usually arrives between mid-November and mid-December in both zones, so it’s ideal to maneuver a frost-tender avocado tree indoors by early November. Always watch weather forecasts as winter approaches, in case of an extra-early frost that may require an unscheduled move.
An Outdoor Alternative
If you’re growing a avocado cultivar such as “Zutano” or even “Stewart” that can withstand temperatures below freezing along with your area generally experiences only mild, brief frosts, you might maintain the tree outdoors during winter without any damage in case you take some precautions. By way of instance, maintaining an avocado tree over the upper portion of this slope helps protect it from cold air, which will drain down the slope. A place near a warm, south- or west-facing wall of a building also offers extra warmth during cold spells, as does wrap the tree’s back with foam to insulate it from chilly. For a young tree, that can be especially cold-sensitive, build a framework above its canopy and curtain it with cloth or towels to provide extra protection from chilly.
Moving Outdoors in Spring
Avocado trees flower at different times, depending on the cultivar, but a lot of types bloom early in spring to produce ripe fruits in summer. It is possible to move a tree outdoors as soon as spring arrives, but it’s a fantastic idea to delay until all risk of frost has passed, because cold weather can damage or ruin flower buds which have started to open. As an instance, if you reside in USDA zone 9, the average date of last frost is often between the end of January and the end of February, while in USDA zone 10, frost usually ends before January 30, although these dates can vary, depending on your geographical area. If you have moved a avocado tree outdoors and you also experience a late frost while it’s in bloom, hang several light bulbs in the branches to provide some warmth or cover the tree with light blankets or sheets until the weather warms.