Getting the lowdown on chill factors

You can find many named cultivars (cultivated varieties) within each type of fruit, and you need to choose one suitable to your climate and growing conditions. Some fruit plants are obviously better-adapted to certain climates than others. Avocados don't work as a crop in cold regions; some pears and raspberries are better in mild areas, and others are adapted to Northern climes; most apples (but not all) like to be cold and North, too. Although you may be able to push your boundaries or cheat a bit in your garden with smaller plants such as perennials, coddling a more substantial resident such as big bush, vine, or tree isn't always practical. (Check out Chapter 3 for info on growing seasons and plant hardiness zones.)

Take your cue from what sorts of fruits appear to be prospering in your area or what's for sale at your local nursery. Call your nearest Cooperative Extension Service office and get recommendations not only for the types of fruits but also for the most suitable and cold-hardiest cultivars within each kind. In the meantime, here's what you need to know about high-chill and low-chill fruits:

1 High-chill: High-chill trees require more hours with temperatures below 44°F (7°C) to break dormancy and grow in the spring. High-chill trees don't perform well in mild climates. Many apples, pears, cherries and deciduous fruit and nut trees are rated by the number of hours of chill they require.

1 Low-chill: Low-chill deciduous fruit trees require fewer hours of with temperatures below 44°F (7°C) in order to break dormancy. These types of deciduous fruits and nuts do best where winters are mild.

Review Table 15-1 for further details on popular trees. Note: Chill hours means the total cold-season hours below 44°F (7°C).

Table 15-1

Chill Requirements of Fruit and Nut Plants

Fruit

Chill Hours

Fruit

Chill Hours

Almond

400-700

Japanese plum*

500-1,600

Apple*

400-1,800

Kiwi*

400-800

Apricot*

350-1,000

Kiwi 'Twei' (female)

0-200

Asian pear (Chinese)

400-600

Kiwi 'Vincent' (female)

0-200

Asian pear (Japanese)

300-750

Mulberry

400

Avocado

0

Nectarine*

200-1,200

Blackberry

200-700

Peach*

200-1,200

Blueberry (Florida)

0-200

Pecan

300-1,600

Blueberry (northern)

700-1,200

Persimmon

100-500

Chestnut

400-750

Pistachio

800-1,000

Citrus

0

Plumcot (apricot-plum cross)

400

Crabapple

300-500

Pomegranate

100-200

Currant

800-1,500

Quince

100-500

European pear

600-1,500

Raspberry*

100-1,800

European plum

700-1,800

Sour cherry

700-1,300

Fig

100-500

Strawberry

200-300

Fruit

Chill Hours

Fruit

Chill Hours

Filbert

800-1,600

Sweet cherry

600-1,400

(hazelnut)

(most)

Gooseberry

800-1,500

Walnut*

400-1,500

Grape

100-500

  • Low-chill varieties that need less chilling are also available.
  • Low-chill varieties that need less chilling are also available.

Was this article helpful?

0 0

Post a comment