Minimizing And Managing Cold Injury In Peaches

Peach Freeze Damaged Flower

The first and most important thing that a grower can do to reduce the potential for cold damage is to choose a good site prior to planting the orchard. For fruit, this is generally high ground that allows for easy drainage of cold air off the site. Low spots or “frost pockets” should be avoided.

Second, the choice of the proper cultivars is critical. Cultivar choice should be based on sufficient cold hardiness for the region in which they will be grown as well as a suitable chilling hour requirement. In temperate areas, low-chill cultivars tend to bloom earlier in the spring than medium- and high-chill cultivars. As a result, they present a higher probability of being at a more advanced stage of flower development (making them more sensitive to cold) when springtime freeze events can occur.

Third, the timing of dormant pruning is important. Because dormant pruning is an invigorating process (it stimulates tree growth in the spring), it is best to delay dormant pruning as long as possible prior to bloom. This may not be practical, however, given the large acreages in many commercial farms and the time required to get all trees pruned effectively on time.

Fourth, orchard floor management can significantly influence springtime orchard temperature. Soil that is devoid of vegetation can absorb more heat during the daytime and liberate (give off) more heat in the nighttime than soil that is covered with vegetation (i.e., sod, weeds, etc.). Similarly, soil that is moist from irrigation or rainfall is also warmer at night than dry soil because of its capacity to absorb more heat during the day and subsequently liberate that heat at night. Under most circumstances, the coldest time of the day in the orchard is immediately before sunrise.

The most difficult freeze conditions to manage occur when it is very cold in combination with high wind speeds (advective freeze). During cold, still nights (radiational freeze), wind machines can be used to stir warm air above the orchard (inversion) back down into the orchard and raise the temperature, potentially averting freeze damage. Depending on the region of the country, some growers may supplement orchard heat by using orchard heaters, burning straw bales, etc.

The appearance of freeze damage differs depending on the timing. If the damage occurs in deep winter, dormant flower buds are killed. Typically, these buds will not swell and they will abscise (drop off) prematurely. Occasionally, however, these buds may swell, but the pistil inside is dead and they will probably abscise shortly thereafter. If damage occurs later, during the various stages of flower development, it is possible to have flowers with a dead pistil but the anthers are still viable. Usually, at these later stages of bloom, however, a brown pistil and withered and brown petals are obvious. Flowers damaged to this extent will abscise. Under most circumstances, flowers on a given fruiting shoot will mature from the apex (shoot tip end) to the base. This means that flowers typically open first at the tip end and last at the base end of a given shoot. If open blooms at the shoot tip are frozen, it is possible that unopened blooms near the base of the shoot may not be lost.

Potential For Late Freeze

Following pollination, once fruit have set and they are beginning to grow, cold damage can still occur. The “Easter Freeze of 2007” was one such occasion when temperatures in the low 20s occurred on three successive days in early April in the southeastern U.S. At this time, fruits were already 1 inch in diameter or larger in some cultivars. Damage to intact fruits was visible on the outside by skin cracking where the cracks would enlarge as the fruit expanded in diameter. When damaged fruits were cut along their longitudinal axis, varying levels of damage to inner tissue (seed and pit/endocarp) were noted. Generally, fruit that were severely frozen dropped off naturally. However, some fruits with damaged seeds remained on the tree and had a deformed growth, never attaining proper size, and being particularly susceptible to infection with brown rot fungus.

To see several photos of freeze damage and to learn more about temperatures that cause cold damage to peach flower buds, please visit my “Everything About Peaches” website and go to the “Frequently Asked Questions (FAQ)” section. Two cold damage FAQs appear in the “Commercial Production” section there.

Leave a Reply

Featured Stories
2017 Florida Strawberry Picking Challenge winners
Berries
February 22, 2017
Florida Strawberry Picking Contest a Big Winner for Charity
Fourth-annual fundraising event brings in more than $100,000 to benefit children of local farmworkers. Read More
Florida potato field in bloom.
Citrus
February 22, 2017
New Insecticide Available to Combat Sucking, Chewing Pests
Minecto Pro from Syngenta has received EPA approval for use in specialty and vegetable crops to control lepidopteran and other pests. Read More
Farm Management
February 22, 2017
Farms Get Bigger Even as the Number of Farms Decline
A new report from USDA shows long-term trends continuing: fewer farms and fewer acres used in farming even as individual operations get bigger on average. Read More
Farm Management
February 22, 2017
Wild Bee Populations Are out of Sync With Crop Needs
Some crops most dependent on pollinators, including pumpkins, watermelons, pears, peaches, plums, apples and blueberries, appeared to have the strongest pollination mismatch. Read More
Basic tractor on the horizon
Citrus
February 22, 2017
Skilled Labor Needed to Keep Agriculture Growing [Opinion]
Even with the challenge of feeding a growing global population at hand, has focus been lost on recruiting where jobs on the farm are need most? Read More
Cartoon sketch of a citrus seed machine
Varieties & Rootstocks
February 22, 2017
Citrus Nurseries Analyze the Need for Seed
It seems many growers are more certain about their scion choices than they are about available rootstocks. Read More
Food Safety Modernization Act moving at snail's pace
Food Safety
February 21, 2017
Food Safety Modernization Act Creeping Forward
Massive regulatory overhaul unfolds as the specialty crop industry hopes to ensure common-sense food safety rules and inspection. Read More
Apples & Pears
February 21, 2017
Snow Doesn’t Stop Day 1 of IFTA Conference
While the Wenatchee, WA, area has experienced higher-than expected snowfall, tour-goers trudge on to learn the latest about advanced production systems and high-value apple varieties. Read More
Grapes
February 18, 2017
Sustainability Is a Growing Factor in Wine Purchasing
California Sustainable Winegrowing Alliance updates certification program, shows sustainability is important part of wine trade. Read More
citrus psyllid closeup
Insect & Disease Update
February 18, 2017
The War on Citrus Psyllids Still Raging
Despite control challenges, keeping the pest in check remains the best approach to managing HLB. Read More
The Latest
Berries
February 22, 2017
Florida Strawberry Picking Contest a Big…
Fourth-annual fundraising event brings in more than $100,000 to benefit children of local farmworkers. Read More
Citrus
February 22, 2017
New Insecticide Available to Combat Suck…
Minecto Pro from Syngenta has received EPA approval for use in specialty and vegetable crops to control lepidopteran and other pests. Read More
Farm Management
February 22, 2017
Farms Get Bigger Even as the Number of F…
A new report from USDA shows long-term trends continuing: fewer farms and fewer acres used in farming even as individual operations get bigger on average. Read More
Farm Management
February 22, 2017
Wild Bee Populations Are out of Sync Wit…
Some crops most dependent on pollinators, including pumpkins, watermelons, pears, peaches, plums, apples and blueberries, appeared to have the strongest pollination mismatch. Read More
Citrus
February 22, 2017
Skilled Labor Needed to Keep Agriculture…
Even with the challenge of feeding a growing global population at hand, has focus been lost on recruiting where jobs on the farm are need most? Read More
Varieties & Rootstocks
February 22, 2017
Citrus Nurseries Analyze the Need for Se…
It seems many growers are more certain about their scion choices than they are about available rootstocks. Read More
Food Safety
February 21, 2017
Food Safety Modernization Act Creeping F…
Massive regulatory overhaul unfolds as the specialty crop industry hopes to ensure common-sense food safety rules and inspection. Read More
Apples & Pears
February 21, 2017
Snow Doesn’t Stop Day 1 of IFTA Conferen…
While the Wenatchee, WA, area has experienced higher-than expected snowfall, tour-goers trudge on to learn the latest about advanced production systems and high-value apple varieties. Read More
Grapes
February 18, 2017
Sustainability Is a Growing Factor in Wi…
California Sustainable Winegrowing Alliance updates certification program, shows sustainability is important part of wine trade. Read More
Insect & Disease Update
February 18, 2017
The War on Citrus Psyllids Still Raging
Despite control challenges, keeping the pest in check remains the best approach to managing HLB. Read More
Citrus
February 17, 2017
How Precision Agriculture Is Helping Far…
New Florida-based organization is seeking to break down barriers between farmers and shoppers by providing a platform to not only show what is grown, but how it's grown. Read More
Grapes
February 17, 2017
Washington Organization Rebrands Itself
Washington Association of Wine Grape Growers unveils new identity at convention, now known as Washington Winegrowers Association. Read More
Berries
February 17, 2017
Florida Blueberry Growers Counting on a …
With last season's disaster in the rear view, all eyes are searching for bluer skies. Read More
Equipment
February 17, 2017
Wanted: Tech Innovators for Drone Challe…
Land O'Lakes Prize offers up $150,000 to help make drones more useable for farmers Read More
Fruits
February 17, 2017
Are Drones the Future of Pollination?
Researchers in Japan have turned drones into robot bees as artificial pollinators. Read More
GenNext Growers
February 16, 2017
Young Start-Up Hort Tech Companies Honor…
Western Growers Center for Innovation & Technology Scholarships promote sustainability. Read More
GenNext Growers
February 16, 2017
Young Farmer Success Act Reintroduced to…
Bill to add young growers to Public Service Loan Forgiveness Program. Read More
Fruits
February 16, 2017
New App Helps Fruit Growers Calculate Ch…
App helps growers calculate chill hours based on locations and models and assess physiological needs of fruit crops. Read More