Specialty Crop Information
The Specialty Crop Information section of VIP is meant as a general source of information pertaining to climate impacts on various types of vegetation. VIP users are welcome to submit anything they wish to help better communicate these interactions. Please send information to vip-info@mrcc.purdue.edu.
(+/-) Chilling Hour requirements by type of fruit
Courtesy of RaintreeNursery.com
Almond | 500-600 | Mulberry | 400 | |
Apple | 400-1000 (low-chill varieties are less) | Peach | 600-800 | |
Apricot | 500-600 | Pear, European | 600-800 | |
Blackberry | 200-500 | Pear, Japanese | 400-500 | |
Blueberry, Northern | 800 | Persimmon | 200-400 | |
Cherry | 700-800 | Plum Cot | 400 | |
Chestnut | 400-500 | Plum, European | 800-900 | |
Citrus | 0 | Plum,, Japanese | 300-500 | |
Currant | 800-1000 | Pomegranate | 100-200 | |
Fig | 100-200 | Quince | 300-500 | |
Filbert | 800 | Raspberries | 700-800 | |
Gooseberry | 800-1000 | Strawberry | 200-300 | |
Grape | 100+ | Walnut | 600-700 | |
Kiwi | 600-800 |
(+/-) How susceptible are fruits and vegetables to cold temperatures?
This table shows a list of fresh fruits and vegetables by freeze susceptibility categories showing relative sensitivities when exposed to freezing temperatures.
Most Susceptible | Moderately Susceptible | Least Susceptible |
---|---|---|
Apricots | Apples | Beets |
Asparagus | Broccoli | Brussels sprouts |
Avocados | Carrots | Cabbage, mature and savoury |
Bananas | Cauliflower | Dates |
Beans, snap | Celery | Kale |
Berries (except cranberries) | Cranberries | Kohlrabi |
Cucumbers | Grapefruit | Parsnips |
Eggplant | Grapes | Rutabagas |
Lemons | Onion (dry) | Salsify |
Lettuce | Oranges | Turnips |
Limes | Parsley | |
Okra | Pears | |
Peaches | Peas | |
Peppers, sweet | Radishes | |
Plums | Spinach | |
Potatoes | Squash, Winter | |
Squash, Summer | ||
Sweet potatoes | ||
Tomatoes |
Source: Table 4.1, Chapter 4 - Frost Damage: Physiology and Critical Temperatures
(+/-) Extreme cold impacts on fruit crops
Peter Hirst and Bruce Bordelon, Purdue Extension
Apples and Pears: These fruits are very hardy, but extremely cold temperatures close to -15°F could produce some bud damage.
Peaches and Nectarines: The rule of thumb is that some flower bud kill occurs at -10°F and for every degree below -10°F, 10% of flower buds are lost. At -20°F, expect complete flower bud mortality.
Sweet and tart cherries: Tart cherries are hardier to extreme cold than sweets. However, temperatures around -15°F is when some bud damage could occur in both sweet and tart cherries.
Blueberries: Highbush blueberries are generally tolerant of temperatures down to -15°F, but an extended period of cold will likely lead to some flower bud kill.
Blackberries: Thorny and thornless blackberries are not hardy below -10°F, so below this threshold, there could be considerable damage to vascular tissue in canes and potentially in the buds themselves. In severe cases, all above ground growth could be killed. Blackberries commonly exhibit a delayed winter injury response where the buds may have survived the winter cold and begin to grow in the spring, but the damage to the vascular tissue in the canes results in collapse of the new growth a few days or weeks after the start of growth.
Raspberries: Red and black raspberries are fairly hardy to cold temperatures, but temperatures around or below -15°F could cause some minimal damage to Midwest varieties.
Grapes: Varieties of grapes can vary widely in amount of damage from extreme cold temperatures. Grapes have a compound bud, with primary, secondary and tertiary growing points. The primaries are usually the first to show cold damage. At temperatures around -15°F, it would be expected that hardy hybrid and American varieties would have 0-25% primary bud damage. This percent loss is management since pruning severity can be adjusted to account for those losses. Less hardy hybrids may have 50% or more bud damage at temperatures around -15°F, which could lead to some yield reduction and potential cane and cordon damage. At temperatures around -15°F, cold tender viniferous varieties likely experience considerable damage to buds, canes, and cordons and possible damage to trunks above the snow line.
Critical low temperatures for specialty crops:
(+/-) Critical temperatures for fruit flower buds
Bud Development Stage1 | Average Temperature (°F) for2 | |
10% kill | 90% kill | |
Apple (Delicious) | ||
Full Bloom | 28 | 25 |
Post Bloom | 28 | 25 |
Pear (Bartlett) | ||
Full Bloom | 28 | 24 |
Post Bloom | 28 | 24 |
Peach (Elberta) | ||
Full Bloom | 27 | 24 |
Post Bloom | 28 | 25 |
Sweet Cherry (Bing) or Sour Cherry | ||
Full Bloom | 28 | 25 |
Post Bloom | 28 | 25 |
Prune (Plum) | ||
Full Bloom | 28 | 25 |
Post Bloom | 28 | 23 |
Apricot | ||
Full Bloom | 27 | 22 |
In Shuck | 27 | 24 |
Green Fruit | 28 | 25 |
Source: Iowa State University Extension
1 For specific bud development state temperature thresholds, please visit the full resource guide from ISU Extension.
2 Under very calm conditions the fruit bud temperature can be lower than the air temperature, resulting in injury when recorded temperatures are slightly above the critical level.
(+/-) Picture table of Fruit Freeze Damage Thresholds
Sample below. Click for PDF file (3 pages)
Source: Michigan State University Extension, Mark Longstroth, 2012
(+/-) Critical temperatures for field crops relative to phenological stage
The table below shows the critical temperatures that could cause damage for field crops (e.g., grain, forage, and silage crops) relative to the phenological stage.
CROP GER | Germination (°F) | Flowering (°F) | Fruiting (°F) |
---|---|---|---|
Spring wheat | 15.8, 14.0 | 30.2, 28.4 | 28.4, 24.8 |
Oats | 17.6, 15.8 | 30.2, 28.4 | 28.4, 24.8 |
Barley | 19.4, 17.6 | 30.2, 28.4 | 28.4, 24.8 |
Peas | 19.4, 17.6 | 28.4, 26.6 | 26.6, 24.8 |
Lentils | 19.4, 17.6 | 28.4, 26.6 | 28.4, 24.8 |
Vetchling | 19.4, 17.6 | 28.4, 26.6 | 28.4, 24.8 |
Coriander | 17.6, 14.0 | 28.4, 26.6 | 26.6, 24.8 |
Poppies | 19.4, 14.0 | 28.4, 26.6 | 28.4, 26.6 |
Kok-saghyz | 17.6, 14.0 | 26.6, 24.8 | 26.6, 24.8 |
Lupin | 21.2, 17.6 | 26.6, 24.8 | 26.6, 24.8 |
Spring vetch | 21.2, 19.4 | 26.6, 24.8 | 28.4, 24.8 |
Beans | 23.0, 21.2 | 28.4, 26.6 | 26.6, 24.8 |
Sunflower | 23.0, 21.2 | 28.4, 26.6 | 28.4, 26.6 |
Safflower | 24.8, 21.2 | 28.4, 26.6 | 26.6, 24.8 |
White mustard | 24.8, 21.2 | 28.4, 26.6 | 26.6, 24.8 |
Flax | 23.0, 19.4 | 28.4, 26.6 | 28.4, 24.8 |
Hemp | 23.0, 19.4 | 28.4, 26.6 | 28.4, 24.8 |
Sugar-beet | 21.2, 19.4 | 28.4, 26.6 | |
Fodder-beet | 21.2, 19.4 | ||
Carrot | 21.2, 19.4 | ||
Turnip | 21.2, 19.4 | ||
Cabbage | 23.0, 19.4 | 28.4, 26.6 | 21.2, 15.8 |
Soybeans | 26.6, 24.8 | 28.4, 26.6 | 28.4, 26.6 |
Italian millet | 26.6, 24.8 | 30.2, 28.4 | 28.4, 26.6 |
European yellow lupine | 24.8, 23.0 | 28.4, 26.6 | |
Corn (maize) | 28.4, 26.6 | 30.2, 28.4 | 28.4, 26.6 |
Millet | 28.4, 26.6 | 30.2, 28.4 | 28.4, 26.6 |
Sudan grass | 28.4, 26.6 | 30.2, 28.4 | 28.4, 26.6 |
Sorghum | 28.4, 26.6 | 30.2, 28.4 | 28.4, 26.6 |
Potato | 28.4, 26.6 | 30.2, 28.4 | 30.2, 28.4 |
Rustic tobacco | 28.4, 26.6 | 28.4, 26.6 | |
Buckwheat | 30.2, 28.4 | 30.2, 28.4 | 31.1, 28.4 |
Castor plant | 30.2, 29.3 | 31.1, 30.2 | 28.4, 32.0 |
Cotton | 30.2, 28.4 | 30.2, 28.4 | 28.4, 26.6 |
Melons | 31.1, 30.2 | 31.1, 30.2 | 30.2, 32.0 |
Rice | 31.1, 30.2 | 31.1, 30.2 | 31.1, 30.2 |
Sesame | 31.1, 30.2 | 31.1, 30.2 | |
Hemp mallow | 31.1, 30.2 | ||
Peanut | 31.1, 30.2 | ||
Cucumber | 31.1, 30.2 | ||
Tomato | 32.0, 30.2 | 32.0, 30.2 | 32.0, 30.2 |
Tobacco | 32.0, 30.2 | 32.0, 30.2 | 32.0, 30.2 |
Source: Table 4.5, Chapter 4 - Frost Damage: Physiology and Critical Temperatures
(+/-) Critical temperatures for citrus fruits, buds or blossoms
Citrus Species | Critical Temperature (°F) |
---|---|
Green Oranges | 28.6 to 29.5 |
Half ripe oranges, grapefruit, and mandarins | 28.0 to 28.9 |
Ripe oranges, grapefruit, and mandarins | 27.0 to 28.0 |
Button lemons | 29.5 to 30.6 |
Tree ripe lemons | 29.5 to 30.6 |
Green lemons (diameter > 0.47 in) | 28.6 to 29.5 |
Lemon buds and blossoms | 27.0 |
Source: Table 4.10, Chapter 4 - Frost Damage: Physiology and Critical Temperatures
(+/-) Highest freezing temperature for fresh fruits and vegetable crops
Field experiments on critical damage temperatures for fresh fruits and vegetable crops are somewhat limited. However, studies have been done on the highest freezing temperatures for fruit and vegetable storage, and those are provided below. As a caveat, the highest freezing storage temperatures in the table might be slightly higher than the air temperature at which damage is expected under field conditions. However, it can still be used as a guide.
BY CROP NAME (Alphabetically)
Name | Temperature (°F) |
---|---|
Acerola (Barbados cherry) | 29.5 |
African horned melon | 31.8 |
Apple | 29.3 |
Apricot | 30.0 |
Artichoke (globe) | 29.8 |
Artichoke (Jerusalem) | 27.5 |
Asian pear, Nashi | 29.1 |
Asparagus (green, white) | 30.9 |
Avocado (cv. Fuerte, Hass) | 29.1 |
Avocado (cv. Fuchs, Pollock, cv. Lula, Booth) | 30.4 |
Banana | 30.6 |
Barbados Cherry | 29.5 |
Beans (snap, wax, green) | 30.7 |
Beans (lima) | 30.9 |
Beet (bunched) | 31.3 |
Beet (topped) | 30.4 |
Berries (blackberries, strawberry) | 30.6 |
Berries (blueberries, dewberry) | 29.7 |
Berries (cranberry, raspberries) | 30.4 |
Berries (elderberry) | 30.0 |
Berries (loganberry) | 28.9 |
Broccoli | 30.9 |
Brussels-sprouts | 30.6 |
Cabbage (Chinese (Napa), Common early/late crop) | 30.4 |
Cactus pear (prickly pear fruit) | 28.8 |
Carambola (Starfruit) | 29.8 |
Carrots (topped) | 29.5 |
Cauliflower | 30.6 |
Celeriac | 30.4 |
Celery | 31.1 |
Cherimoya (custard apple) | 28.0 |
Cherry (sour) | 28.9 |
Cherry (sweet) | 28.2 |
Chicory | see Endive |
Chilies | see Pepper |
Citrus (Calamondin orange) | 28.4 |
Citrus (Calamondin orange - AZ, CA, FL, dry and humid areas) | 30.0 |
Citrus (lemon) | 29.5 |
Citrus (lime, Mexican, pummelo) | 29.1 |
Citrus (orange - AZ, CA, FL, dry and humid areas, blood orange, Seville (sour)) | 30.6 |
Citrus (tangelo, minneola) | 30.4 |
Citrus (tangerine) | 30.0 |
Chives | 30.4 |
Coconut | 30.4 |
Collards, kale | 31.1 |
Corn (sweet and baby maize) | 30.9 |
Cucumber, slicing | 31.1 |
Currants | 30.2 |
Custard apple | see Cherimoya |
Dasheen | see Taro |
Date | 3.7 |
Dill | 30.7 |
Eggplant | 30.6 |
Endive, Escarole | 31.8 |
Fennel | 30.0 |
Fig | 27.7 |
Garlic bulb | 28.4 |
Gooseberry | 30.0 |
Grape (fruit) | 27.1 |
Grape (stem) | 28.4 |
Grape (American) | 29.5 |
Horseradish | 28.8 |
Jujube (Chinese date) | 29.1 |
Kale | 31.1 |
Kiwano | see African horned melon |
Kiwifruit | 30.4 |
Kohlrabi | 30.2 |
Leafy greens (cool/warm season) | 30.9 |
Leek | 30.7 |
Lettuce | 31.6 |
Longan | 27.7 |
Loquat | 28.6 |
Mango | 29.5 |
Melons (cantaloupes, netted melons) | 29.8 |
Melons (casaba) | 30.2 |
Melons (Crenshaw, honeydew, orange-flesh) | 30.0 |
Melons (Persian) | 30.6 |
Mombin | see Spondias |
Mushrooms | 30.4 |
Nashi | see Asian pear |
Nectarine | 30.4 |
Okra | 28.8 |
Olives (fresh) | 29.5 |
Onions (mature bulbs, dry) | 30.6 |
Onions (green onions) | 30.4 |
Papaya | 30.4 |
Parsley | 30.0 |
Parsnip | 30.4 |
Peach | 30.4 |
Pear (European) | 28.9 |
Peas (pod, snow, snap, sugar) | 30.9 |
Peppers (bell peppers, paprika, hot peppers, Chiles) | 30.7 |
Persimmon, kaki (Fuyu, Hachiya) | 28.0 |
Pineapple | 30.0 |
Plantain | 30.6 |
Plums and Prunes | 30.6 |
Pomegranate | 26.6 |
Potato (early/late crop) | 30.6 |
Pumpkin | 30.6 |
Quince | 28.4 |
Radish | 30.7 |
Rhubarb | 30.4 |
Rutabaga | 30.0 |
Salsify (vegetable oyster) | 30.0 |
Sapotes (Caimito, star apple) | 29.8 |
Sapotes (Canistel, eggfruit) | 28.8 |
Sapotes (Black sapote) | 27.9 |
Sapotes (White sapote) | 28.4 |
Shallot | 30.7 |
Spinach | 31.5 |
Squash (Summer (soft rind); courgette) | 31.1 |
Squash (Winter (hard rind); calabash) | 30.6 |
Star-apple | see Sapotes |
Starfruit | see Sapotes |
Strawberry | see Berries |
Sweet potato (yam in USA) | 29.7 |
Tamarind | 25.3 |
Taro (cocoyam) | 30.4 |
Tomato (mature green; firm ripe) | 31.1 |
Turnip root | 30.2 |
Watercress | 31.5 |
Watermelon | 31.3 |
Witloof chicory (endive) | 31.8 |
Yam | 30.0 |
BY CRITICAL TEMPERATURE
Temperature (°F) | Name |
---|---|
3.7 | Date |
25.3 | Tamarind |
26.6 | Pomegranate |
27.1 | Grape (fruit) |
27.5 | Artichoke (Jerusalem) |
27.7 | Fig, Longan |
27.9 | Sapotes (Black sapote) |
28 | Cherimoya (custard apple), Persimmon, kaki (Fuyu, Hachiya) |
28.2 | Cherry (sweet) |
28.4 | Citrus (Calamondin orange), Garlic bulb, Grape (stem), Quince, Sapotes (White sapote) |
28.6 | Loquat |
28.8 | Cactus pear (prickly pear fruit), Horseradish, Okra, Sapotes (Canistel, eggfruit) |
28.9 | Berries (loganberry), Cherry (sour), Pear (European) |
29.1 | Asian pear, Nashi, Avocado (cv. Fuerte, Hass), Citrus (lime, Mexican, pummelo), Jujube (Chinese date) |
29.3 | Apple |
29.5 | Acerola (Barbados cherry), Barbados Cherry, Carrots (topped), Citrus (lemon), Grape (American), Mango, Olives (fresh) |
29.7 | Berries (blueberries, dewberry), Sweet potato, yam [in USA] |
29.8 | Artichoke (globe), Carambola (Starfruit), Melons (cantaloupes, netted melons), Sapotes (Caimito, star apple) |
30.0 | Apricot, Berries (elderberry), Citrus (Calamondin orange –AZ, CA, FL, dry and humid areas), Citrus (tangerine), Fennel, Gooseberry, Melons (Crenshaw, honeydew, orange-flesh), Parsley, Pineapple, Rutabaga, Salsify (vegetable oyster), Yam |
30.2 | Currants, Kohlrabi, Melons (casaba), Turnip root |
30.4 | Avocado (cv. Fuchs, Pollock, cv. Lula, Booth), Beet (topped), Berries (cranberry, raspberries), Cabbage (Chinese (Napa), Common early/late crop), Celeriac, Citrus (tangelo, minneola), Chives, Coconut, Kiwifruit, Mushrooms, Nectarine, Onions (green onions), Papaya, Parsnip, Peach, Rhubarb, Taro (cocoyam) |
30.6 | Banana, Berries (blackberries, strawberry), Brussels-sprouts, Cauliflower, Citrus (orange - AZ, CA, FL, dry and humid areas, blood orange, Seville (sour)), Eggplant, Melons (Persian), Onions (mature bulbs, dry), Plantain, Plums and Prunes, Potato (early/late crop), Pumpkin, Squash (Winter (hard rind), calabash) |
30.7 | Beans (snap, wax, green), Dill, Leek, Peppers (bell peppers, paprika, hot peppers, Chiles), Radish, Shallot |
30.9 | Asparagus (green, white), Beans (lima), Broccoli, Corn (sweet and baby, maize), Peas (pod, snow, snap, sugar) |
31.1 | Celery, Collards, kale, Cucumber, slicing, Kale, Squash (Summer (soft rind); courgette), Tomato (mature green; firm ripe) |
31.3 | Beet (bunched), Watermelon |
31.5 | Spinach, Watercress |
31.6 | Lettuce |
31.8 | Endive, Escarole, Witloof chicory (endive), Chicory (see Endive), Chilies (see Pepper), Custard apple (see Cherimoya), Dasheen (see Taro), Kiwano (see African horned melon), Leafy greens (cool/warm season), Mombin (see Spondias), Nashi (see Asian pear), Star-apple (see Sapotes), Starfruit (see Sapotes), Strawberry (see Berries) |
Source: Table 4.4, Chapter 4 - Frost Damage: Physiology and Critical Temperatures. For critical damage temperatures (°C) by development stage for apples, apricots, cherries, peaches, pears, prunes, and grapevines, see Tables 4.7 and 4.8 on this page.
(+/-) Lower development thresholds for crops
During the growing season, crops have upper and lower development thresholds outside of which they don’t develop physiologically. For example, the upper and lower development thresholds for corn are 86°F (upper) and 50°F (lower). The assumption is that development of corn is limited once the temperature exceeds 86°F or falls below 50°F.
The lower development threshold is also called the “base temperature” or Tbase. These thresholds are used when calculating growing degree days for specific crops. The equation for growing degree days is:
Using the “Degree Day” tool on cli-MATE, the user can specify the base temperature for the growing degree day calculation (Station Data > Daily > Degree Days). For more information on Growing Degree Days, please visit here: http://mrcc.purdue.edu/resources/growing-degree-day-description
The tables below show the base temperature (Tbase) for many specialty crops, sorted by crop name and by base temperature.
BY CROP NAME
Crop | Base Temperature (Tbase) (°F) |
---|---|
Asparagus | 40 |
Barley | 40 |
Bean, snap | 50 |
Beet | 40 |
Broccoli | 40 |
Carrot | 38 |
Collards | 40 |
Corn | 50 |
Cucumber | 55 |
Eggplant | 60 |
Flaxseed | 40 |
Lettuce | 40 |
Muskmelon | 50 |
Oats | 40 |
Onion | 35 |
Okra | 60 |
Pea | 40 |
Pepper | 50 |
Potato | 40, 45 |
Rice | 50 |
Rye | 40 |
Sorghum | 50 |
Soybeans | 50 |
Squash | 45 |
Strawberry | 39 |
Sunflower | 45 |
Sweet corn | 50 |
Sweet potato | 60 |
Tomato | 50 |
Watermelon | 55 |
Wheat | 40 |
BY BASE TEMP
Base Temperature (Tbase) (°F) |
Crops |
---|---|
35 | Onion |
38 | Carrot |
39 | Strawberry |
40 | Asparagus, Barley, Beet, Broccoli, Collards, Flaxseed, Lettuce, Oats, Pea, Potato, Rye, Wheat |
45 | Potato, Squash, Sunflower |
50 | Bean (snap), Corn, Muskmelon, Pepper, Rice, Sorghum, Soybeans, Sweet Corn, Tomato |
55 | Cucumber, Watermelon |
60 | Eggplant, Okra, Sweet Potato |
Source: Oregon State University Small Farms