Day 73 - Container Planting During Arctic Blasts

One of our containers this morning when the temperature read 12 degrees (F).

This good info below is about protecting container plants and was sent out by our Tennessee Extension Agent Mark Holcomb when we learned that this weeks temps were going down to 8 degrees (F).

Protect your plants like you do babies: cover them to keep them out of wind, keep their body warm, and do not let it dry out.

Only warm blooded creatures are affected by wind chill; but, strong winds will blow the cold temperatures into the cracks, between containers and under the overwintering blankets.

If you read this Sunday or Monday, Dec 12-13; what can you do?

1- Shove or jam containers inside houses if not already done.

2- Container growers can add any sort of supplemental heat available in overwintering houses. Exhaust fumes can damage plants if the house is tight and it is run for several hours, but not as bad if there is some fresh air leaking in.

3- An extra sheet of poly (any color) or shade cloth can be laid over the more tender crops after jamming or shoving them (holly) inside the overwintering houses, but it needs to be sealed to the ground, to trap the heat from the earth. Foliage may be killed that touches the poly so figure something out. Shove pots tight first.

4- I hope the roots are moist, as dry roots are damaged worst. I doubt you can or want to irrigate today, but if you can, do so if the root balls are not moist. Any ice that forms will insulate and be beneficial. Then drain the lines again.

5- Same with dug B&B, water the balls if possible. Any ice that forms will insulate and be beneficial. Best protection for dug B&B is to slip back into hole; if not shove together and cover with sawdust or wood chips.

6- Any sort of overwintering blanket, shade cloth or poly can be laid over containers left outside or B&B laid over. Foliage may be killed that touches the poly, so lay shade cloth over the plants first. Use anything that might trap some heat and shield the plants from the wind (wind will lower the temperature and dry the entire plant out).

7- Snow and ice are good insulators, (it would be great to have a snow making machine to create snow and blow over the containers and B&B plants that are outside.)

8- My cell is 931-224-5353 if you have a question

9- Summary: jam, trap heat, keep moist, shield from wind, and protect the roots.

10- Our plants should be well acclimated to the cold and be very dormant. I think and hope.

11- I realize you had already done the normal things: cover overwintering houses around Thanksgiving, shoved containers tight, covered containers left outside with overwintering blankets and seal the blanket tight to the ground.

12- Click on my web site below my name, click on handouts on left of the home page, and look at the 2 “Root Killing Temperature” handouts under the General section.

13- Holly, mahonia, dogwood, boxwood, cotoneaster, magnolia are some of the more tender items.

Mark A. Halcomb

UT Area Nursery Specialist

Warren Co. Extension

201 Locust St., Suite #10

McMinnville, Tenn. 37110

mhalcomb@utk.edu