I was having lows in single digits two days in a row with a known low of 2 degrees F, and not above freezing day and night from Friday through sometime the following Tuesday last week. I also lost power for two hours and couldn’t get generator started Friday morning as temperatures plunged to 8 degrees with a high that day of 11 degrees. All of my store-quality citrus have massive leaf damage but no trunk splits noted yet. Most of my Citradia trees, Dunstan, 80-5, Thomasville, Benton citrange that are unprotected only showing mild to moderate leaf damage. One large citradia on east side of an unheated cold frame with yuzu in it actually looks unscathed for now. The yuzu in unheated frame looks remarkably good with some leaf damage only.
I had to cut back on my use of space heaters due to inadequate amount of electricity to support my 15 outdoor trees in cold frames covered in 4 mil plastic sheeting. Each frame has potted citrus seedlings and grafted trees also. The poncirus hybrids even the newly grafted potted ones are unscathed.
My winners for this event so far with only one 250 watt space heater inside each enclosure are:
Saint Anne Satsuma ; only a few burnt leaves.
Seedless Changsha on flying dragon; few burnt leaves only.
Meiwa kumquat ; no leaf damage but lost all fruit.
Trees with moderate leaf damage in frames:
Croxton
Owari
Kimbrough
Seville sour orange : all fruit lost
Bergamot
Yuzu: unheated frame w 50 gallon water barrel
Trees with severe leaf loss:
Rio Red grapefruit : fruit lost
Changsha : unprotected
Shiranui
Sugar Belle
Ichang lemon
All frames have at least one water barrel and all at least one 250 watt space heater w larger frames having two heaters and two or three barrels.
I’m having another electric outlet installed outside by electrician next Monday.