Frost preparations will depend on crop stage and minimum temp forecast for your area (2pm, Thur., March 1, 2018)
I was just in touch earlier today with Dr. Mark Hoffmann, Small Fruit Extension Specialist, NCSU, and I said that I would appreciate an opportunity to weigh in regarding the colder temperatures headed our way over this weekend, and into next week.
For the next week or so, we are fortunately not looking at anything like what happened here last March, but for growers with early blooming varieties, like Sweet Charlie, there is potential for blossom-damaging “white frosts” in some areas as early as this weekend! I am afraid these frosty conditions will continue into next week as well.
So, let’s get started with some updates from the field
Our first grower to provide a crop update is Eric Hunter, Easley, SC, and I really think his comment about how this season is shaping up to be another “early season” is particularly appropriate – he is anticipating being open 2 weeks earlier…
1. Eric Hunter of Easley, South Carolina (near Clemson)
Luckily, we are NOT dealing with anything remotely like the freeze conditions of last March (2017)…thank goodness!
2. Danny Van Meter, Clarkson, KY
We have a lot of buds and near popcorn/popcorn stage blossoms. At this point, I’m not 100% sure. We have rain all day today and the covers will be soaked, plus we have high wind warnings tomorrow afternoon through Saturday evening. Right now, I am leaning towards not doing anything. I have several growers just south of me who are loaded with open blooms.
Fig. 2. Many of you are familiar with this table that shows a photo of the actual flower stages (tight bud next to pencil, popcorn just below pencil, and open blossom to left), and the table below the photo indicates the critical temperatures for each of these stages. For example, the emerged buds that are not yet open are very hardy, and can handle temperatures as low as 20 F. But, when you reach the popcorn and open blossom stages, the crop is MUCH MORE VULNERABLE for frost damage. PLEASE NOTE that the 27-28 F critical temp for open blossoms ONLY applies to situations with DRY AIR. I am afraid that the types of frosts we will be experiencing in this weekend and into next week, can cause serious injury even at 30 F ~ assuming these are going to be “white frosts.”
3. Rob Woodard, Hertford, NC
I met Rob at the Virginia Winter Strawberry School in VA Beach on Tuesday (2/27), and he sent this note today (3/1):
4. John Gross, Sanford, NC (Sandhills)
I spoke with John last night from my home in Williamsburg, VA. I used to visit John’s farm just south of Raleigh quite often when I was at NC State. Basically, John has about 15 open blossoms with some green fruit as well on his Sweet Charlie! That is a lot of exposed crop. So, we carefully looked over all the different forecast information for his area, and something that got my attention this morning is how the AWIS 10-day forecast for Sanford, NC, has changed overnight, and now he is possibly looking at a frost on Sunday morning (3/4) according to this latest AWIS forecast Sanford – AWIS 3.1.18
As of last evening, AWIS was not forecasting a frost in Sanford area for Sunday morning: Sanford- Feb 28, 2018 at 7:20 p.m.
So, things are changing! And, I am glad that John has taken some precautions to “cover up” his Sweet Charlie, and John also told me that his Camarosa are about “half as far along” as the Sweet Charlie (7-8 open blossoms). He pulled the row covers yesterday (ahead of today’s rain and some of the high winds expected Friday), and his plan is to leave them in place through the middle of next week. AWIS is saying there will be frost in Sanford area forecast each morning from Sunday through Wednesday. There is a good possibility that Thursday morning (3/8) could be even colder? But, winds are expected to be higher Wed night/Thursday morning, and less potential for frost formation Thursday morning.
Check out your AWIS forecast!
If you have as many as 10-15 open blossoms right now, you definitely need to carefully study the AWIS forecast below, and look at the row that is 3rd from the bottom that begins with “DEWF” and see if an “F” for frost is indicated. But, beaware that a lot can change in the next 24-48 hours with these forecasts, and Mark and I will be working together to keep publishing these important AWIS updates until we get past this patch of frosty weather!
Wind issues: In the Sanford area, for example, winds will finally begin to die down in late afternoon on Saturday (3/3) for easier application of row covers. At this point, row covers appear to be the best option. Sprinkling can be effective, but winds could still be “up” in the 7-8 mph range on Monday morning
Sprinkling option – because of winds in the forecast for Sun/Mon in Sanford, for example, you would need to start-up sprinkling before the wet bulb temp drops below 33 F — around midnight to 1 a.m. on Monday morning (3/5) (see the AWIS table for early Monday morning). Here is a nice review of the do’s and dont’s of sprinkling:StrawberryPlasticulureAdvisoryApril1505
State by State 10-Day Detailed AWIS forecasts (note: immediately by each state name is the 7 day max/min temp table — this table covers even more locations in each state than the AWIS 10-day detailed forecast)
Maryland – MD Min Temp 7 days
Virginia – VA Min Temps for 7 days
North Carolina NC Min Temp 3.1.18
South Carolina – SC AWIS 7 Day
Georgia – Ga AWIS 7 day
AWIS Weather Services, Inc. Western Kentucky Frost/Freeze Forecast Produced at 504 a.m. CST on Thu Mar 1 2018 ... Forecast for Tonight ... Southwest Kentucky NWS Fcst Zones 1-13 **** NEAR FREEZING COLD LOCATIONS **** **** LITTLE IF ANY FROST DUE TO WIND **** Lowest Temperatures: 35 - 38 Murray Min 38 Range Dewpoint Temps: 30 - 43 Range Wetbulb Temps: 32 - 48 AVG Wind Direction/Speed: NW 10 AVG Sky Condition: Clear Extended Forecast: Range of Lowest Min Temperatures in the Above Zones Min Temps Valid For Morning of Given Date (May NOT include ALL cold pockets) 03/03/18 03/04/18 03/05/18 03/06/18 03/07/18 03/08/18 -------- -------- -------- -------- -------- -------- 30 - 33 31 - 34 40 - 42 35 - 39 30 - 34 26 - 28 -------- Grayson County Area NWS Fcst Zones 23-24,26-28,61-63 **** FREEZE COLD LOCATIONS **** **** LITTLE IF ANY FROST DUE TO CLOUDS/WIND **** Lowest Temperatures: 31 - 36 Leitchfield Min 34 Durations at/below 32: 0 - 2 Range Dewpoint Temps: 27 - 40 Range Wetbulb Temps: 33 - 47 AVG Wind Direction/Speed: NW 16 AVG Sky Condition: Mostly Cloudy Extended Forecast: Range of Lowest Min Temperatures in the Above Zones Min Temps Valid For Morning of Given Date (May NOT include ALL cold pockets) 03/03/18 03/04/18 03/05/18 03/06/18 03/07/18 03/08/18 -------- -------- -------- -------- -------- -------- 26 - 31 26 - 32 32 - 40 35 - 40 29 - 33 21 - 26 -------- For more detailed information visit www.awis.com or call 888-798-9955. Copyright 2018 AWIS Weather Services, Inc. All rights reserved.
Will the Skybit weather be offered this year for strawberry growers? I haven’t seen any info on it and found it very beneficial for our operation last year here in Kentucky at Fox Farms. If so, I want to sign up and also send an application to a new grower in Harrodsburg, KY that Danny Van Meter got started this season.
Hi Troy – I am still doing this at cost. You can send me an email at:
and I will send you the details – I can still get you signed up for a 3 month subscription. My winter season has been unusually busy this year, and I did not send out as many reminders about this service as I should have. For growers who don’t know what we’re talking about, here is an example of SkyBit for Danny Van Meter – note it will be pretty cold Saturday morning in his location!