Jury out on April frost damage to area apple trees
News - May 9, 2012 Edition
SOUTH DUNDAS —
Although three area apple growers say their orchards were affected by the unusually heavy frosts that occurred on the weekend of April 28-29-30, the jury is still out on how this fall’s apple crop will fare.
Also in jeopardy were the ‘strawberry’ plants which are expected to be in bloom within the next week or two and ready for harvest by mid June.
It all began with the unseasonably ‘hot’ weather in mid-March which put most plant-life into early bud production.
It culminated on the frosty final weekend in April, when the apple trees and berry plants were a bit farther along in their bud production than would be normal for the time of the year, and therefore, more susceptible to frost damage.
“We have had some damage, but what is left on the (apple) tree is still sufficient to support a normal crop,” says Paul Dentz at Dentz Orchards and Barry Farm located on the Brinston Road north of Iroquois.
“But we can’t afford to lose any more. At this point, we are very optimistic that we will still have a normal crop.”
Bill Barkley at Barkley’s Farm on the Robertson Road north of Morrisburg agrees. “It is hard to know until September, but when the apples start budding they can take some frost. You can check them at this point, but you don’t know what is going to happen.”
“You need at least five per cent of your blossoms and you can still get a good crop,” said Barkley.
Sandra Beckstead at Smyth’s Apple Orchard on County Road 18 west of Williamsburg, was slightly less optimistic.
“A lot of our blossoms were frozen,” said Beckstead. “As soon as you get the tip, that’s the blossom and that’s the apple.”
Beckstead says their trees “were a month ahead of schedule. It goes back to that one week in March when everything jumped.”
Although she says there are still going to be apples, “it is now just a wait and see.”
In the meantime it is business as usual. “We are getting the bees in tomorrow (Friday, May 4), and we will do all of the normal work. You have to look after it and hope for the best.”
The Smyth Orchards are the largest in the area with some 30,000 trees on 120 acres.
At the Dentz Farm, Paul and brother Calvin, did not leave the fate of their berries and apples to mother nature.
With the weather predictions leading into the weekend, they watched the temperatures closely and were prepared to take what action they could to assist.
They explain that both wind and cloudy conditions help prevent frost as both help to hold the escaping warm air closer to the ground.
According to a Ministry of Agriculture printout “frost occurs when the temperature around the plant drops blow 0º Celcius (32º Farenheit). At this temperature, pure water forms ice crystals on surfaces which have fallen below the freezing point of water. Plant sap is not pure water; therefore, strawberries have a lower freezing point than 0ºC
On the weekend in question, “the wind saved us on Friday night.”
“The stage we were at with the buds (apples trees) was that they could take temperatures to -3,” says Paul. “But it went to -5/-6.”
“By 8 p.m. on Saturday evening, we were reaching critically damaging temperatures at ground level. So at that point, we got our irrigation system going (on the strawberries), and we ran it for 12 hours, overnight Saturday and into Sunday morning,” says Paul. “We did the same thing on the Sunday night and into Monday morning.”
“The long and short of it is, we were able to save our strawberry crop.”
“While spring frosts are generally less threatening to the apples than they are to strawberries, on occasion you do have a situation,” says Paul of the weekend in question.
“As the sun leaves, the warmer air radiates upwards and warmer temperatures are found at 30-40-50 feet,” explains Paul. “ So how do you capitalize on that?”
“Ten to 15 km per hour wind is enough to keep it mixed,” says Calvin, but when there is no wind, intervention is required.
And so, for the two cold mornings in question, a helicopter was rented.
“Beginning at about 3 a.m. (both mornings), the helicopter flew at seven mph at an altitude of 50 feet, pushing the warmer air back down to the ground where we needed it,” says Paul.
Because apple trees produce more buds/blossoms than they can support as apples, a limited amount of damage to a portion of the buds may not necessarily affect the quantity of the harvest.
Temperatures on the weekend of April 29-30 did vary throughout the area, and the cold was experienced throughout Ontario and into Quebec. The extent of the damage will vary in all areas depending on how cold it got and at what stage the apple bud was at.
The trees at the Dentz Orchard were in stage four, the tight cluster, of their bud development at which the temperature dipping to -3.9ºC would result in about a 10 per cent loss. At -7.9ºC you could expect bud damage at about 90 per cent.
As the bud progresses into the next stages in the next couple of weeks….first pink bud, full pink, first bloom, full bloom and post bloom...they become more sensitive to low temperatures. Through these critical stages growers do not want to experience temperatures approaching anything near -2ºC to - 3ºC range.
Damaged or not, the crab apple and apple trees are now heading into first and full bloom. Even those that have been damaged will blossom, but the tips (within the clusters) that were damaged are unlikely to produce fruit.
Area growers are now looking for good pollination weather which means good flying weather for the bees and after that a summer of normal rainfall and normal sunshine to fill our apple baskets.
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