Louisiana citrus farmers are preparing for damaging cold conditions later this week. Still, not all crops face the same level of vulnerability. The LSU AgCenter is sharing a chart that rates the hardiness of those fruit trees. Kumquat trees are best suited to handle the sub-freezing conditions, with satsumas also a hardy variety. Lemons and limes are most susceptible to the cold, as a general rule.
There are three main factors involved in determining freeze susceptibility of citrus trees:
1) The type and age of the citrus. In order from most cold hardy to least cold hardy: satsuma, kumquat, orange, grapefruit, lemon and lime. A citrus tree also increases in hardiness as it gets older. Trees with larger, denser canopies deal with the cold better as they trap more heat.
2) Threshold temperatures are approximately 20 degrees for satsumas and kumquats, and about 26 degrees for all other citrus.
3) The duration of the sub-freezing temperature is very significant. If the temperature is below freezing for 24 to 36 hours, damage can usually be expected.
Source: wbrz.com