“Deep” Freezes & Plant Impacts


There have only been two light frosts so far this fall but now we dealt with two nights of temperatures in the mid-twenties. Both mornings there was a hard and heavy frost on everything.

Nov. 30’s prediction was for a low of 28° for the area but here the low was 24.4° and it was in the mid-twenties for 6 hours.

Dec. 1’s prediction was for a low of 30° but it went down to 24.5° and stayed in the mid-twenties for 7.5 hours.

Oddly there was no breeze much less a wind either night.

Used our new freeze blankets (0.9 oz./SY) and bags (2.1 oz. per sq. meter) to protect the plumbagos, Meyer lemon trees, Birds Nest ferns in pots, ginger plants, and staghorns. Mop Head hydrangeas were hit hard as were all the usual things like basil and Vincas. The Southside of the large plumbagos next to the house was damaged even under the frost blankets.

The much heavier bag was on the heavily laden westmost Meyer Lemon but it still had freeze damage on the leaves in the top-most area of the bag. See advice below.


  • Frost cloths and the heavy bag on the Meyer Lemons did not protect some leaves.
  • There was no frost protection on the Blood Red Oranges, Satsumas, or little Hamlin Oranges and no damage.

Several days ago we had a good rain so everything was well watered.


PlantNo EffectStung*Killed
Beets – 2-3 leafX
Beets – 6″+X
Bok Choy – small and matureX
Broccoli, Waltham 29, MatureX
Broccoli, Waltham 29, smallX
Broccoli, Green Magic, 6″-8″X
Cabbage – K-YX
Cabbage – Early Jersey Wakefield, matureX
Cabbage – Early Jersey Wakefield – 6″X hard
Chard – Leaf BeetX
Chard – PeppermintX
Chard – LuculusX
Lettuce – smallX
Lettuce – 2 leafX
Mustard – Mature Florida BroadleafX
Mustard – Florida Broadleaf, 2-leafX
Mustard – Mature SavannaX
Radish – MatureX-Cherry Belle
Radish – smallX
Radish – DiakonX
Spinach – Small & 2-leafX
Squash – All Butternuts X
Onions – Multiplying, Red, Bunching, & GreenX

12/1/2020 – Pulled out and hauled away all squash vines and pepper plants.

From IFAS about Citrus — Freeze damage symptoms and recovery for citrus.

Care of citrus trees that have been freeze-injured must be dependent on
factors such as time of year at which the freeze occurs, condition of the trees at time of injury and weather conditions immediately following injury. These factors will influence the type of approach to use for recovery of freeze-damaged trees. The natural reaction after a freeze is to do something right away, although there is very little that can be done at that time, as it is impossible to determine the full extent of injury. Twigs and branches may continue to die for a period of several months to a couple of years following a severe freeze.

No attempt should be made to prune or even assess freeze damage until the new spring flush gets fully expanded and mature. Therefore, no pruning should be done until late in the spring or the summer after a freeze. This delay is desirable since it is difficult to determine the actual extent of freeze injury until new growth commences and fully develops. In early spring, freeze-damaged trees often produce new growth that soon dies back. Sufficient time should be given for the dying back to cease and for the
new healthy growth to take place and fully expand.

Experience has shown that early pruning does not promote recovery and that delaying pruning to the proper time will save money. Pruning cuts should be made into living wood and, where possible, at crotches, leaving no stubs or uneven surfaces. It is advisable to remove heavy brush fromthe grove immediately following the pruning operation.

Fertilization of freeze-damaged trees should be reduced until the
trees are back to their original canopy size and foliage density. Fertilizer
should be applied more frequently, but rates should be reduced in proportion to the amount of tree damage and to the expected crop load. Growers and production managers should make wise decisions based upon their local situation. For example, trees suffering 10 to 15 percent wood loss should receive a regular nutritional program as fruit will be produced that year. Trees suffering 50 to 60 percent wood loss most likely will not produce fruit that year, and the nutritional program should be reduced according to the damage. Nutrient deficiency symptoms may be intensified in freeze-damaged trees due to the drain entailed by the large amount of growth necessary to replace lost foliage. Thus, foliar sprays of micronutrients (copper, zinc, manganese and boron) will be beneficial to new growth. Nitrogen, phosphorus, potassium, magnesium and calcium should also be applied to satisfy the needs of the trees and to increase leaf size because trees tend to produce small leaves for a few years after suffering severe leaf loss.

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