Frost in Forecast for Sun / Mon (10am, Saturday, March 18, 2017)

— Written By

Fig. 1. Minimum temps for Monday morning – white frost is a real possibility, and growers need to assess their crops today to see if it might be worth frost protecting Sunday/Monday. In cases were crops were badly frozen last Wed morning (March 15), there may be no real benefit. But, if you have live flower buds and popcorns, it will be important to consider protection. Also, on Sunday (tomorrow), we will be previewing the weather outlook for the next 2 weeks – be sure to check that out later on Sunday evening (about 9 pm).

Good morning,

I appreciate a number of nice phone calls from strawberry growers over the last few days to express their appreciation for these advisories and taking time to look at their individual situations, and offer suggestions on how to handle one of the worst freeze episodes any of us can ever remember. When I wrote the advisory,

Big problem for “water throwers” tonight (9:26 am, Tue., 3/14/17)

I had no idea just how destructive this Tue/Wed freeze would be. It was truly devastating in its effects, and I have gathered that a number of growers who went with irrigation alone and could not keep sprinklers going, had very serious losses. The row cover story has been mixed – when I wrote an advisory the next day (Wed, 3/15), I was of the impression that the row covers had done a very good job of protecting against what I called the “Big Daddy” of windborne freezes, but the next 2 cold events (Wed/Thur and Thur/Fri), revealed the serious limitations of a row cover strategy when temperatures fall into low 20s and teens. The “hard freeze” of Thur/Fri also revealed limitations in our capability to forecast just how cold it would get Friday morning — in locations we were expecting 25 minimum, it went to 19! Further, the temperature gradients from the ground level (canopy level) to just 5-6 ft above the crop, were also shocking (it was common to see 5 degree differentials).

Today, growers are assessing their crop situations, and trying to decide whether they need to do anything about the frost coming this Sun/Mon. In this advisory I will concentrate on this particular cold event, but I do wish to suggest that in situations where you had only row covers this past week, that it would likely be valuable to take measures to protect your crop, despite your losses. Strawberry plants are simply amazing how they spring back to life! And, I would invite you to closely inspect the condition of your emerged tight buds, and I happen to think you will be seeing pretty good livability with that stage.

Where I am most concerned is with crops that were irrigated on Tue/Wed, and the irrigation system subsequently froze up. You should inspect the the emerged flowers buds on these plants first, and see if some of the less advanced flower buds survived? If your plants have a blackened look, I recommend that you cut into some of the crowns to assess the condition of the internal crowns? You can just search “crown damage” on this website for photos of what this damage looks like. Here are 3 older advisories that focused on such damage:

Crown and flower bud damage related to Feb 19/20 freeze (noon …

Mar 21, 2015 But, this amount of internal crown damage is not as concerning to me as the … Each strawberry inflorescence may produce 15 or more fruit, …

https://strawberries.ces.ncsu.edu/…/crown-and-flower-bud-damage-related-to- feb-1920-freeze-noon-sat-32115/

Cold Injury To Strawberry Crowns | North Carolina Cooperative …

Mar 8, 2010 Freezing injury in strawberry is easily seen by cutting the crownsCrownstructure: The strawberry crown is actually a much shortened plant stem. …. it also has better shelf-life and resistance to rain damage than Chandler.

https://strawberries.ces.ncsu.edu/…/cold-injury-to-strawberry-crowns/Situation where the grower elected to sit this one out:   I just spoke to a grower in Faison area who elected to “do nothing” Tue/Wed with one block of plants, and these are actually showing new popcorn blooms today that will protection against this next go round.

Situation where the grower elected to sit this one out (Tue/Wed windborne freeze):   I just spoke to a grower in Faison area who elected to “do nothing” Tue/Wed with one block of plants (did not have irrigation or covers), and these are actually showing new popcorn blooms today that will protection against this next go round.

Interesting observation from call this morning – where the grower relied pretty much on one or two row covers, the blossom losses were still quite extensive in his Camino Real variety. The Caminos are more moderate in plant size than Camarosa. The large Camarosa bushes had only 10% bloom damage!

Question on sprinkler heads freezing up

Barclay,
One of my grower’s sprinkler heads were freezing up (stopped turning) the first two “rounds” of these crazy nights and they had spent the night running about knocking the ice off of them. Last night, they had gone out in the day and applied WD-40 to the heads. In the morning they reported that only two heads stopped all night, and they just tapped the ice off of them and the started back.
Is WD-40 something regularly used like this, or that we recommend?

Thanks,

Tom Dyson

County Extension Director
North Carolina Cooperative Extension Service
Lincoln County, NC

Reply – I seen “Pam” cooking oil spray work as well. Last week I posted this photo of a white lithium grease product (got this photo on Amazon), and this can work as well. A very large strawberry grower in Louisiana told me yesterday that they have been through some horrific windborne freeze events over the years (apparently, one went to 5 F), and they always spray their nozzles with Pam and/or lithium grease. He also shared an excellent suggestion of using gallon milk jugs for placing over nozzles that are getting frozen up, and the water still coming out of nearly frozen nozzle will effectively wash the ice off.

AWIS HOURLY FORECAST

Here are the AWIS hourly forecasts in this next section. I decided to take a peak at the situation in Greenboro, NC, Greensboro – Hourly Detailed Weather Forecast – and, they will potentially see some (white) frost around 5 am Monday morning. This will be a more familiar radiation frost with temperatures that will be hovering around the freezing mark at the canopy  level. This type of frost could be damaging to open blossoms, but is unlikely to affect emerged flower buds.

NC

We are now closely watching for potential frost on Thursday (3/23) as well

10-DAY DETAILED HOURLY WEATHER FORECASTS

Ahoskie-Tri-Cou Albemarle_AP Andrews Asheboro
Asheville_Munic Beaufort-Michae Boone_NC Burlington-Burl
Cape_Hatteras_AG Chapel_Hill-Hor Charlotte Cherry_Point
Clinton_NC Concord_NC Currituck_NC Edenton-Northea
Elizabeth_City Elizabethtown_NC Erwin-Harnett_C Fayetteville_AP
Fort_Bragg/Simm Franklin/Macon_C Gastonia-Gaston Goldsboro_AFB
Goldsboro_NC Greensboro Greenville_AP_NC Hickory
Jacksonville Jacksonville_(A Jefferson_AP_NC Kenansville-Dup
Kill_Devil_Hills Kinston_AP Lexington-David Lincolnton_AP
Louisburg_NC Lumberton_AP_NC Mackall_AAF Manteo/Dare_Co
Maxton Mcalf_Bogue_Fiel Monroe_AP_NC Morganton-Morga
Mount_Airy-Moun New_Bern North_Wilkesbor Oxford_NC
Piney_Island_Bom Pope_AFB Raleigh-Durham Reidsville_AP
Roanoke_Rap_AP Roanoke_Rapids_R Rockingham_NC Rocky_Mount-Wils
Roxboro_AP Rutherfordton Salisbury-Rowan Sanford_NC
Shelby_AP_NC Smithfield_AP Southern_Pines Southport_NC
Statesville-Sta Tarboro_AP Wadesboro_AP Washington-Warr
Whiteville_NC Wilmington_AP_NC Winston-Salem

MD

10-DAY DETAILED HOURLY WEATHER FORECASTS

Aberdeen Andrews_AFB Annapolis_Naval Baltimore_Sci_Ce
Baltimore/Wash Cambridge/Dorche College_Park_AP Cumberland_AP
Easton_MD Fort_Meade Frederick_MD Gaithersburg_AP
Hagerstown_AP Leonardtown Middle_River Oakland_MD_AP
Ocean_City_AP Patuxent_River Salisbury Stevensville_AP
St_Inigoes/Webst Washington_DC_AP Westminster_AP

Virginia

10-DAY DETAILED HOURLY WEATHER FORECASTS

Abingdon Ashland_VA Charlottesville Chesapeake-Ches
Culpeper Danville Dublin/New_Riv Emporia_VA
Farmville Fentress_Naval_A Fort_Belvoir/Da Fort_Eustis/Fel
Franklin/J_B_Ro Hillsville Hot_Springs/Ing Jonesville_AP
Langley_AFB Leesburg/Godfre Louisa-Louisa_C Lynchburg
Manassas_Muni(A Marion/Wythev Martinsville Mecklenburg/Bru
Melfa/Accomack Newport_News Norfolk_Hampton_ Norfolk_NAS
Norfolk_VA Oceana Orange_VA Petersburg_(AWO
Quantico Richlands_AP Richlands_VA Richmond
Richmond_Chester Roanoke Shannon_Arpt Stafford_AP_VA
Staunton-Shenan Suffolk-Suffolk Tappahannock_AP Virginia_Tech_A
Wakefield_AP Wallops_Island Warrenton_Fauqui Washington_Dulle
West_Point_VA Williamsburg_VA Winchester_Rgnl Wise/Lonesome_P

South Carolina

10-DAY DETAILED HOURLY WEATHER FORECASTS

Aiken_AP Anderson_Co_Air Barnwell_AP Beaufort_Cnty_AP
Beaufort_SC Bennettsville_Je Camden_AP Charleston_Exec_
Charleston_Muni Cheraw_AP Chester_AP Clemson-Clemson
Columbia-Columb Columbia/McEnti Columbia_Metro Conway_AP
Darlington Florence_SC Georgetown_AP_SC Greenville_Donal
Greenville_Down Greenville-Spart Greenwood-Green Hartsville_AP
Hilton_Head_AP Kingstree_AP Lancaster-McWhir Laurens_AP
Manning_AP Marion_AP_SC Moncks_Corner_AP Mount_Pleasant_A
Myrtle_Beach Newberry_AP North_Myrtle_Be Orangeburg-Oran
Pickens_AP Rock_Hill Spartanburg_Down Summerville_AP
Sumter_AP Sumter_SC Walterboro_AP Winnsboro_AP

Georgia

10-DAY DETAILED HOURLY WEATHER FORECASTS

Albany_Municipa Alma/Bacon_Co Americus_AP Athens_Municipa
Atlanta/DeKalb Atlanta/Fulton Atlanta_Intl_Ar Atlanta_Paulding
Augusta/Bush_Fi Augusta_Daniel_F Bainbridge_GA Blakely_AP
Brunswick_GA Brunswick/Glync Canton_GA Carrollton_AP
Cartersville_AP Claxton_AP Columbus_GA Covington_GA_AP
Dalton-Dalton_M Douglas_Muni Dublin/WHBarron Fitzgerald_AP
Fort_Benning Ft_Stewart/Wrig Gainesville_AP_G Greensboro_GA
Homerville_AP Hunter_(AAF) Jesup_AP La_Grange
Lakeland Lawrenceville_AP Macon_AP Marietta
Marietta/Cobb Milledgeville_AP Moultrie_Muni_AP Newnan-Newnan_C
Peachtree_City Rome_GA Savannah Statesboro_GA
Swainsboro_AP Sylvania_AP_GA Thomaston_AP Thomasville_AP
Thomson_GA Tifton_AP Valdosta Valdosta/Moody
Vidalia Warner_Robins_A Washington_GA Washington_GA
Waycross_AP Winder_AP

Kentucky

10-DAY DETAILED HOURLY WEATHER FORECASTS

Bowling_Green Covington Danville-Powell_ Fort_Campbell
Fort_Knox/Godma Frankfort_AP Glasgow_KY Henderson_City
Jackson_KY Lexington_KY London_Corbin Louisville_AP
Louisville/Bowm Middlesboro_AP Monticello_KY_AP Murray_AP
Owensboro_AP Paducah Richmond_Madison Somerset(AWOS)

Written By

Photo of Barclay Poling, N.C. Cooperative ExtensionDr. Barclay PolingFormer Professor and Extension Specialist, Strawberries and Muscadines (919) 515-5373 (Office) barclay_poling@ncsu.eduHorticultural Science - NC State University
Updated on Mar 18, 2017
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