What is the difference between cool season and warm season vegetables?


What is the difference between cool season and warm season vegetables?


Cool Season Vegetables

Cool season vegetables grow best in cool temperatures.  They will tolerate a light frost with some withstanding a freeze event with little to no damage.  Most produce and finish in the vegetable garden before the high temperatures of summer arrive.  While some cool season vegetables will tolerate warm temperatures, the quality of the produce often decreases.  For example, radishes will be more fibrous with an unpleasant taste when grow in warm temperatures.  Certain cool season vegetables, like kale and Brussels sprouts, will have higher quality, better-tasting produce when exposed to below-freezing temperatures. 

Cool season vegetables can be planted as early as early to mid-April in central Iowa and as late as early May, with most harvested by early summer. (approximately one week earlier in southern Iowa and one week later in northern Iowa).  Some cool season vegetables can have a second crop planted in late summer for a fall harvest.

Warm Season Vegetables

Warm season vegetables grow best in warmer temperatures.   They are not frost tolerant and will experience damage, sometimes significant, when exposed to below-freezing temperatures. Some may even show damage at temperatures slightly above freezing. 

Warm season vegetables should not be planted until the danger of frost has passed, typically early May in central Iowa (approximately one week earlier in southern Iowa and one week later in northern Iowa).  Most are ready for harvest by mid to late summer, and those vegetables that produce continuously can be harvested regularly until the first frost, which is typically early October in much of Iowa.

Cool-Season Vegetables 

  • Asparagus
  • Beet
  • Bok Choy
  • Broccoli
  • Brussels Sprouts
  • Chives
  • Cabbage
  • Carrot
  • Cauliflower
  • Celeriac & Celery
  • Chard
  • Chinese Cabbage
  • Daikon
  • Endive
  • Escarole
  • Fava Bean 
  • Finocchio/Florence Fennel
  • Garlic
  • Horseradish
  • Kale
  • Kohlrabi
  • Leek
  • Lettuce
  • Mustard
  • Onion
  • Pak Choi
  • Parsley
  • Parsnips
  • Pea (snap, snow, English)
  • Potato
  • Radish
  • Rhubarb
  • Rutabaga
  • Salsify
  • Scallions
  • Shallot
  • Spinach
  • Swiss Chard
  • Turnip
  • Watercress

Warm-Season Vegetables 

  • Cantaloupe
  • Cucumber
  • Eggplant
  • Green Bean
  • Lima Bean
  • Muskmelon
  • Okra
  • Pepper (bell, hot)
  • Popcorn
  • Pumpkin
  • Soybean (Edible)
  • Summer Squash (zucchini, crookneck, pattypan, chayote, etc.)
  • Sweet Corn
  • Sweet Potato
  • Tomato
  • Tomatillo 
  • Watermelon
  • Winter Squash (acorn, delicata, butternut, spaghetti, Hubbard, etc.)

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