Popular articles

Chilling requirement

Written by Dr Wayne Boucher

One of the impacts predicted for climate change is milder winter temperatures.
Most of our major fruit producing regions are planted with varieties selected to match the temperatures typical for each region. Low chill varieties for regions with mild winters, medium chill and high chill for regions with cold winters.

What will happen with these varieties if average winter temperatures increase into the future?

Many of these varieties may not receive sufficient winter chilling to produce viable crops. The amount of cold needed by a plant to resume normal spring growth, following the winter period, is commonly referred to as its ‘chilling requirement.’

Plant species as well as horticultural varieties vary widely in their winter cold requirement.

---Topics in this article---

  • What happens during winter chilling
  • Measuring winter chilling
  • Result of insufficient winter chill
  • Use of dormancy breaker Dormex to substitute for lack of winter chill
  • Anatomical changes within buds during chill accumulation
  • Sectioning buds
  • Application


  • Table 1. Chilling requirements for fruit types
  • Table 2. Typical symptoms of insufficient winter chilling. The results have been verified in other USA States.
  • Table 3. Chilling information for use in applying Dormex to peaches in Alabama.

About this website

This website presents articles from the Tree Fruit magazine. 
Here you can find information about fruit growing under specific topics (found in the menu)
REGISTER - and you can read complete feature articles without interruption.

Like what we do?

We produce and distribute Tree Fruit magazine. 
AND we design and maintain this and other websites. 
Discover what we can do for you.
Contact us

FTM logoEmail

Our services

Fruit Tree Media can design your website and have you 'live and on the net', in no time.

We understand crop production practices and inputs (horticulture and broad acre) so you spend less time explaining and more time refining your message.

We can provide a full service including writing and photography. See our website for more information or contact us.

Back to top