UC Master Gardeners of Butte County
University of California
UC Master Gardeners of Butte County


Got Gardening Questions?

Visit or call the Hotline
Wednesday 9am-12pm
Thursday 1-4pm

Call: 530-538-7201

Or drop by: The Butte County Cooperative Extension Office
2279-B Del Oro Avenue
Oroville, CA 95965

You can also catch us in person at local farmers markets or at one of our information booths. Check out where we'll be on the Events page.

Help Us Help You

You never can tell what's at the root of the problem. Below are some questions we may ask when you call:

  • Name of plant
  • Age of plant
  • Soil type (loam, sandy, clay)
  • Current watering methods (drip, sprinkler, hand)
  • Frequency of watering
  • Sun exposure
  • Evidence of insects or other damage – check on both sides of leaves
  • Recent changes that may effect the plant (watering, fertilizing)

Samples and photos related to your question are strongly encouraged. Drop them by the office any time, or email them to:

Include a description of the problem.

What’s Hot Now?


by Barbara Hill

I keep seeing “chill hours” listed on fruit and nut tree tags. What are they, and why are they important?

Like Goldilocks and her porridge, trees don’t want the weather to be too cold when, after a long winter’s nap, they produce new, tender buds – but they don’t want to wait until it’s too hot, either, because they’ll miss out on a full season of growth and fruiting. How does a tree know when it’s “just right” to resume growth?

Trees produce hormones in the fall which stop growth processes and initiate a state of rest. Even though dormant trees appear to be asleep, fruiting trees and shrubs are still paying attention, and keeping track of the temperature – specifically, chilling (roughly, temperatures between 32F and 45F degrees, also known as winter chill or vernalization). Growth inhibiting hormones will keep the trees safely in dormancy until a certain amount of winter chill has been accrued. This prevents them from being fooled into growth during spring-like midwinter warm spells and, when the right number of chill hours has been reached, signals that it’s the optimal time to break winter dormancy.

Chill requirements can vary widely, depending upon the tree type and variety. In general, a tree’s chilling requirement should come close to the amount of winter chill normally received in the area where it’s planted. If varieties with higher requirements are grown in milder climates, too little chilling will mean that blooming and leaf regrowth may be delayed, and fruit set will be poor. Conversely, if a tree with a low chill requirement is grown in colder climes, it will break dormancy too soon and suffer late-winter freeze damage.

Fortunately for Butte County gardeners, most of Northern California receives between 800 and 1500 hours of chilling each winter. This means that most commercially available fruit and nut trees will find our climate “just right.”

For more information:
The California Backyard Orchard: Tree Selection


What's Hot Archive

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