Cherry chill hours

Chill hours, Cherry chill hoursCherry chill hours requirements vary significantly between the different cherry tree varieties.

Deciduous fruit trees require a rest period during winter. This phase is called chill accumulation requirements or needs. These requirements are the result of the climatic adaptation of the different fruit species to their environment. Breaking the sleep depends on the accumulation of chill hours. This is a way that fruit trees have to reference the beginning of spring and protect themselves from the sudden changes in temperature that usually happen during winter.

Until the necessary chill hours accumulate. The tree does not leave its sleeping state. In case of chill hours deficiencies, the cherry blossom becomes irregular.

Calculation and consequences of not completing chill hours

There are several ways to calculate chill hours, the most common is to count the hours below 7ºC.

A correct exit from rest is essential for deciduous fruit trees to produce.

The shortage of chill hours produces the following symptoms:

1.- The opening of wood and flower buds is delayed.

2.- The sprouting of the tree is irregular or staggered, sprouting some branches before others.

3.- The tree is detached from the flower buds, preventing the production of fruit.

Finally, the severity of the symptoms described above will depend on the difference between the chill requirements and the chill that the tree has received during the resting phase.

Cherry tree chill hours

The following data have been published by the breeders of the varieties or by data published by research centers (IMIDA). They are arranged according to the estimated chill hours needs for different cherry tree varieties.

Low chill cherry trees (Brooks, Early BigiRoyal Tioga…). And popular cherry tree varieties BurlatVan, Bing and Lapins cherry chill hours.

Cherry varietyChill hours 7ºCChill Units (Utah)Flowering time
Cristobalina314510Extra-Early
Royal Tioga500Extra-Early
Royal Hazel500Early
Brooks519854Early
Early Bigi571934Early
Lapins592963Early
Satin600Early
Burlat 604934Half
Ruby610968Early
Bing623993Half
Primulat629972Early
Sweet Heart6491019Half
New Star6541028Early
Van6681036Half
Santina6711039Half
Utah Giant800Half
Sylvia800Late
Kordia900-1,000Late
Summit1,100Late
Regina1,000-1,200Late

As we can see, the cherry tree varieties with less chill requirements are early flowering. In contrast, late flowering varieties have high chill hours requirements.
This is due to the relationship between the accumulation of chill hours and the departure from winter rest.

Importance of chill hours in cherry production

Precise planning of the chill hours to which our cherry plantation will be exposed is essential. In areas with little accumulation of chill hours during winter, the cherry crop may not be feasible.

Recommended reading

Did you find our article interesting about the cherry chill hours requirements? We recommend the following articles on our website:

Collection of pests and diseases of the cherry tree.

Types of rootstocks for cherry trees.

Stella cherry tree

Warning

We have translated the information on our website from Spanish to English. Note that some words may have seen their meaning altered during their translation.

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