What Growers Are Finding Out This Morning… (3/22/13)

— Written By Barclay Poling


Figure 1. Photo by NC Strawberry Grower Kevin Hall (Friday morning)


Figure 2. A second photo from this morning by grower Kevin Hall, Charlotte, NC


Figure 3. A third photo by Kevin Hall (3/22/13)

A. General Reports from the Field

1) Kenneth Rudd, Greensboro (low 20 F)

<phone interview>  A max/min thermometer (accurate) was placed under a new 1 ounce cover before this cold event, and it was learned that the minimum under the new cover this morning (around 7 a.m.) was right at 30 F. Last night they checked at 10 p.m. and it was 36 F under this cover. {editor’s note:  I know a lot of growers had issues with not being able to measure bloom temps with a digitial therm, but that did not mean you couldn’t crawl under (a few rows) to read a Taylor thermometer}. The Rudds are already wet enough and don’t like to run water unless absolutley needed. It would appear that their bet to rely on the row cover paid off. As of a few minutes ago they could only see blossoms hurt that were right on the outside rows of the row covers and where the cover was pressed tight against the blooms (those are dead).

Other growers in their region had to run sprinklers (not enough covers), and they are still running water now (9:54 a.m.), and will not be able to shutdown until near noon. These growers were “breaking ice” at 4 a.m. It was definitely a tough night for growers who went with sprinkling. Apparently winds were really up and down all night in some areas. When the winds finally laid down this morning around 7 a.m. was when lowest temperatures were reached (agian, the Rudds indicted a low at 7:20 a.m. of 20 F – he allowed that this particular instrument may not have been as accurate).

2) from Joey Knight (3/21/13) Danville area

I have been outside most of the day visiting farms. The Danville, Virginia radio station is calling for 23 degrees tonight. I have 1.5 oz row covers on and around 9:00 p.m. I will turn my drip irrigation on and let it run all night. I have done this for the last 3 years during these cold snaps and it seems to work because the well water is a lot warmer than the air temperatures which helps release warmer temperatures with the help of the row covers. I have never seen any research on this but it has worked on our farm for the past three years with now bloom losses. The long range forecast in our area is suppose to be cold nights thru April 10.

3) from Tom Baker, VA Beach (3/22/13, 9:30 a.m.)


First and foremost, thank you so much for being part of “our” night last night.
Now, back to the real world. And that ain’t too good this morning.
I recorded for my records “what happened” last night. Here is summary for you:

·        Low, sensor on porch floor, 28 F

·        Low, sensor in outdoor unit of house heat pump, 26 F (fairly low to ground, entire unit is only 48” tall, don’t know where in unit the sensor is)

·        Nearby WeatherUnderground:   low 25.3 F (5:58 a.m., below 26 F from 5:40 until 7:25 a.m.) Ugh!

Low DP 10.8 F ~ 3 a.m., rose a little after that.

Winds:  0 mph from 6:23 until 6:43 a.m.

Avg. winds midnight until 7:47 a.m.:  2.7 mph.

·        WB calculated using 1/3 DP suppression method:  19.4 F at 8 a.m.

CHESAPEAKE: (general summary from three WeatherUnderground sites nearby):
·        Low:  25.3 to 26.5 F, generally at/near 7:25 a.m. One site had “low” from 7:14 until 7:39 a.m.)

·        Low DP:  9.3 to 14.1

·        Winds:  0.4 to 1.0 mph, lowest winds started anywhere from 2:23 to 5:20 a.m., depending on site and stayed lowest until 6 to 8 a.m.)

Robbie Vaughan and I talked on the phone driving home from the dinner and decided to run our drip irrigation. Robbie dripped his fields and high tunnel (no row cover in his tunnel; he did add a propane heater last night). We dripped both Pungo and Chesapeake.

I/we have heard of growers “dripping” to help protect from cold. We figured dripping with 50 F water (we both use wells) could not hurt??? Robbie and I both had portions of fields under row covers (about 65% for us) and uncovered.

Questions:  Has there been any research on this “drip” strategy??? Or any “good” anecdotal observations that you would trust???

Final observation:  When drip is run for 10 hours, the beds get saturated. The water has to go somewhere. Much water in our row middles this morning! I had planned do fungicide sprays today Chesapeake and tomorrow Pungo, but we’ve got a wet mess in the middles now so I hope we can spray tomorrow afternoon in front of rain forecast for Sunday. Also, how much fertilizer did we leach away last night? Just as soon as the beds dry out, we’ll get back on another N drip!

Also, we ran Ridomil Gold in both fields last Friday (March 15). Is our Ridomil gone now? Did it have enough time to get into the plants and do its good? Or should we reapply Ridomil? What would Frank Louws say on this one?


Tom Baker’s report from 3/21-3/22 (night before – a few areas had frost the previous evening in VA and NC. Here is Tom’s report:


I did not read to the bottom of this message (your p.s.) yesterday. Don’t know if Va. Beach growers responded to your frost question. Yes, we had a hum-dinger frost yesterday (Thursday) morning.

Also:  We did have a little frost on the ground this morning (Friday), even with the low dewpoints! (Nothing on vehicles, etc.)  Just before direct sunlight was shining on the ground, I observed the shimmer of frost crystals in the short grass in our barnyard. It was about 7:40 a.m., temp at that time was 26.4 F; DP was 13.6 F. So the temp in that grass fell at least down to 13.6. Arrrgh! It was not frozen dew as the air was too dry for any dew last night. It was frost.
Tom & Anne Baker and Amanda McCann
Brookdale Farm

3) Lowell Yoder, VA (near Lynchburg)…about 21 F at 7 a.m.

(3 a.m. note) Unfortunately, I wasn’t able to start dripping due to frozen hoses and pipes etc. I broke a couple of valves  because things are just so brittle in the cold. I guess it involves more preparation then I gave it. We’re hanging in the mid 20’s so I’m optimistic and we were able to get most of the early varieties double covered. I’m really liking this option and may retire row covers a bit earlier with this in mind.

Not much else to do  to do but go back to bed and evaluate in the morning. Thanks for your help and thoughts on this matter.

Lowell Yoder

4) McKenney VA…the drip idea was a lifesaver

Dr Poling

Thanks so much for your updates and help. We ran drip last night from midnight on. Lowest point was  19 degrees outside and 28 degrees under 1.2 oz cover with a digital thermometer without thermocouple. The idea to run drip was definitely a lifesaver for us.

Thanks again.

Tim Miller
Westover Farm
McKenney, VA

5) Mt Olive Grower

<phone interview>  I have used the drip under covers on previous occasions when I became concerned about frost forming beneath the covers (this actually was a problem in a previous season when we got a frost under the cover), and this approach works – it got rid of the ice crystals that were starting to form…


Dr. E. Barclay Poling
Professor Emeritus/Extension Strawberry Specialist
Department of Horticultural Science
Campus Box 7609, 162A Kilgore Hall
NC State University
Raleigh, NC 27695-7609
919-418-9687 (Cell)
919-515-2505 (Fax)