Strawberry Plasticulture Advisory (3/2/02 9am)
Vol. 3 No. 16 - Barclay Poling, Editor & Ext. Small Fruit Specialist,
NC State
Saturday morning debriefing from the week just past…
-1. Agents and Growers Share Important Lessons: (unedited)
a) Milton Parker, Agent - Robeson and Columbus Co., NC
"Tommy Stone had 16 F just outside the cover last night (2/28-3/1)
and it was 27 F beneath the cover…I think we have an extension success
story in the making here in Columbus Co."
b) Powell Smith, Agent - Lexington Co., SC
"Thanks for all of the help during the freezes over the years. It
means a lot to the growers and agents to know that someone in the know
is looking out for us. I have received many positive comments from growers
about your helpful nature. It is too early to really tell about the actual
level of success that we had around here. I have talked to many growers
and looked at the local fields. Our low on Thursday AM ranged from 19
- 21 at Clinton Sease's and Mike Keisler's; the winds had essentially
stopped by midnight. It appears that they both had relatively good success
at protection. At my house (no berries) lower down the hill, it was 15.
On Friday, once again there was no wind with temps in the low 20's. Good
clear ice formation. I think that we might have made it....whew. I will
look at the first of the week and give you an update after I hear from
the other growers and agents around the state.
c) Eric Hunter, Grower - SC (2/27-2/28)
Dr. Poling,
Here is some interesting data from our farm in the foothills of SC last
night.
By 11PM the winds had died down and we reached our forecasted low of 14
degrees - by 2AM we were at 9 degrees. At 4AM we reached our morning low
of 7 degrees, where it remained until shortly after sunrise.
We had approximately 80% of our acreage under row covers since Saturday.
We did not irrigate on top of the covers.
Plants under row-covers: The AIR temps remained about 5-6 degrees warmer
underneath the row covers as opposed to the real air temperatures...we
didn't measure bud or crown temps. At noon today, I crawled underneath
some of the row covers to inspect. Open flowers were burned up(which were
minimal amounts), but it appears that the vast majority of all 'popcorn'
buds that were tucked close inside the plant survived, and perhaps all
of the unopened buds that have emerged >from the crown.
Plants not under row-covers: All of the emerged buds were lost, but many
of the buds that were tucked tightly inside the top of the crown appear
to have made it through the night - I did find some 'tight' buds that
were lost, but I found many more that survived. I will be monitoring these
closely over the next several days.
This is the first year we've used row covers. Overall, I would say that
the $3000 dollars spent on the covers this year paid for themselves twice
over last night!
Thanks,
Eric Hunter
d) Dan Copeland, Grower - TX
Dr. Poling,
I know you are busy - will keep this brief. Here is our accounting of
4 acres of plants in central Texas.
Overall, we are appear to be slightly of your crops.
• Sweet Charlie-- - 25 - 30 opened blooms/green fruit per plant,
few ripe - anticipated opening in two weeks
• Camarosa -- 10 - 15 opened blooms per plant
• Chandler -- 6 - 8 opened blooms per plant
14 degrees for a low Tues morn. - 18 hours below freezing, 8 hours below
25, 2 degree dewpoints, 27% humidity, after a day of 20 - 30 mph sustained
winds - wind went calm at 7pm Monday.
• plants uncovered - all lost - even the smallest unopened tight
bloom -- new foilage burned
• plants with 1 cover (1.5 oz) --- newly opened blooms killed, 50%
of popcorns killed, tight buds OK
• plants with 1 cover (1.5oz) + drip running all night -- 40% of
newly opened blooms killed, rest OK (no drip freeze ups)
• plants with an old shredded cover underneath and a new cover on
top ---- no damage
my lesson: don't throw away the old shredded
covers, use them underneath in situations like this.
I assume you guys have manufactured a frost cover roller of some type.
I have made one that makes it very easy for us to deploy and pick up the
covers. On average, my wife and I can cover our 4 acres in about 2 hours
(assuming we have sand bags already in the field). Removing the covers
takes a little longer - about 5 hours.
Good luck tonight and tomorrow night (our forecasts are showing another
blast coming Monday).
Dan Copeland
Sweet Berry Farm
Marble Falls, Texas
f) Aaron Goode, Grower - VA (2/28-3/1: very low temp. of 12-13 F,
very low dewpoint <10, and using impact sprinklers)
"I had the worst night of freeze protection I can ever remember last
night…I knew something was wrong when my sprinkler heads started
freezing up in the first hour of irrigation…at the house it was 15
F, and in the field it had to be 12-13 F at 3am. If we hadn't had the
row covers in place, I don't think I'd have much of anything left. In
hindsight, I would not have started the irrigation
system up at all if I'd known it was going to be this cold (<15
F) and with such a low dewpoint. It is nearly impossible to keep impact
sprinklers turning under these conditions. I did not have any wind either."
-2. Irrigation on top of row covers - will require non-impact sprinklers under severe winds and/or low dewpoints:
When Nancy Edwards in TN contacted me last weekend about the severe conditions
headed her way (Fig. 1), it was not clear to me at the time how vitally
important a comment she made about her non-impact wobbler sprinklers would
be (on 30 x 30 spacing)…the near tragedy at a farm in VA on Thu/Fri
(using impact sprinklers) underscores the vital necessity of moving to
this new technology of non-impact sprinklers (no flapper, no springs to
freeze up) "if" we are to
successfully battle severe cold, high winds and/or low dewpoints.
Fig. 1. This AWIS minimum temperature map proved quite accurate and growers
in TN did experience lows in the single digits last week.
-3. The consequence of "doing nothing" this past week?
Every season I have a number of growers tell me, I didn't do anything
during those freezes when everyone else was staying up all night, and
I had the prettiest crop ever! Rather than get into a debate of this kind,
let's just let the pictures of the crop at Clayton tell the story of the
consequences of "doing nothing" were on 2/27-2/28.
Fig. 2. "What were the consequences?" On 2/28/02 at approximately
6 pm I took this photo of flower buds (in various stages) and open blossom
(far left) from a single Camarosa plant - there were several more emerged
flower buds on the plant in addition to those shown in the photo. In assessing
the damage from the windborne freeze night (2/27-2/28), I was somewhat
surprised to see the extent of the injury at Clayton in plots where we
had purposely left uncovered (the majority of plots had a 1 oz cover).
Only the middle flower bud in the picture survived; the one just above
the dime was killed as was the one on the far right. Obviously, the open
blossom was killed. This level of injury "appears" to be correlated
with a low of 22-23 F (I am in the process of upgrading my temperature
sensors in the field and this is a weather shelter temp at Clayton).
Fig. 3. The sample in Fig. 2 was taken from the second inside row plot
that was left uncovered 2/28-2/28. All of the covered plots had nearly
perfect protection - we did lose some of the open blossoms - but it was
not our goal to try to save open blossoms. Our objective with the row
covers was to keep the emerged flower buds (tight stage) alive. We have
found that the very early season open blossoms at this stage (Feb-early
March) produce relatively poor quality fruit - very rough in shape.
Fig. 4. Close-up of crown of row covered Chandler plant. In the proximity
of the newly emerging leaves (center), you can see some very small flower
buds (Chandler is not so advanced as Camarosa - one more reason Chandler
gets high marks for adaptation to our climate).
Fig. 5. From this Chandler main crown I pulled these 2 flower buds to
show that both are still alive (at least up until my visit). You just
need to cut through the buds with your thumbnail to see whether a flower
bud survived or not - looking for bright yellow and green tissues, and
live buds also feel turgid, or full, when you first grasp them. Dead buds
have a hollow feel when you squeeze them. We are "beginning to think"
that small flower buds of this size are hardy to lower temperatures than
previously thought - it could be that these will survive down to even
20 F from an experience with a Chandler crop in VA where the grower went
to 12-13 F outside his covers (early morning on 3/1), but the Chandler
inside the covers were basically O.K. - 1 oz product was used. If you
double-up covers, you essentially have perfect protection. We'll be gathering
a lot more information soon about the relative benefits of single layer
vs double layer covers from our Mountain study in Laurel Springs (Fig.
5)
Fig. 6. One of the few warm places we could find on Wed. afternoon at
the Upper Mountain Research Station, Laurel Springs, was under this double
cover! It was 11 F warmer underneath this cover at 5 pm vs. outside (20
F). We can't wait to see some of this data - it went below 7 F in the
field early Thur. Morning!
Have a good weekend!
E. Barclay Poling, Small Fruit Specialist
Campus Box 7609
Kilgore Hall - Office 252
NC State University
Raleigh, North Carolina 27695-7609
919.515.1195
919.515.2505 (fax)
919.418.9687 (mobile)
|
advisories
| events
| berrybeat
q&a | agent
info | proceedings
| weather
| pest
info|special
reports | regional
experts |
all
material © Barclay Poling
site designed and maintained by: LiquidSun
d e s i g n
