Listing of the major vegetables and the “best” time to plant.
Cabbage
Indoor growing time prior to transplanting: 5 to 6 weeks
Germination time: 10-12 days
Seed planting depth: 1/2 inch
Temperature range for optimal germination: 70-80°F
Optimal growing temperatures** day: 60-70°F night: 50-60°F
Outdoor plant spacing: 12-18 inch
Days to maturity: 60-110
Cool-Season or Warm-Season Crop: Cool-season
Suited for plastic mulch and drip irrigation: No
When to plant outdoors: 4 weeks before last frost***~
Harvesting characteristics: When heads are solid but not yet cracking
Cauliflower
Indoor growing time prior to transplanting: 5 to 6 weeks
Germination time: 10-21 days
Seed planting depth: 1/4 to 1/2 inch
Temperature range for optimal germination: 70-80°F
Optimal growing temperatures** day: 60-70°F night: 55-60°F
Outdoor plant spacing: 18 inch
Days to maturity: 50-72
Cool-Season or Warm-Season Crop: Cool-season
Suited for plastic mulch and drip irrigation: No
When to plant outdoors: 4 weeks before last frost~
Harvesting characteristics: when head is compact but before curd opens and becomes “ricey”
Broccoli
Indoor growing time prior to transplanting: 5 to 6 weeks
Germination time: 10-14 days
Seed planting depth: 1/4 to 1/2 inch
Temperature range for optimal germination: 70-80°F
Optimal growing temperatures** day: 60-70°F night: 50-60°F
Outdoor plant spacing: 18-24 inch
Days to maturity: 50-72
Cool-Season or Warm-Season Crop: Cool-season
Suited for plastic mulch and drip irrigation: No
When to plant outdoors: 4 weeks before last frost~
Harvesting characteristics: when buds are tight and head is compact
Brussels Sprouts
Indoor growing time prior to transplanting: 5 to 6 weeks
Germination time: 7-14 days
Seed planting depth: 1/4 to 1/2 inch
Temperature range for optimal germination: 70-80°F
Optimal growing temperatures** day: 60-70°F night: 50-60°F
Outdoor plant spacing: 18-24 inch
Days to maturity: 90-120
Cool-Season or Warm-Season Crop: Cool-season
Suited for plastic mulch and drip irrigation: No
When to plant outdoors: 5 weeks after last frost
Harvesting characteristics: when plump, firm and glossy
Head Lettuce
Indoor growing time prior to transplanting: 5 to 7 weeks
Germination time*: 7-10 days
Seed planting depth: 1/8 inch
Temperature range for optimal germination: 65-75°F
Optimal growing temperatures** day: 60-70°F night: 60-70°F
Outdoor plant spacing: 12 inch
Days to maturity: 40-90
Cool-Season or Warm-Season Crop: Cool-season
Suited for plastic mulch and drip irrigation: No
When to plant outdoors: 1-2 weeks before last frost~
Harvesting characteristics: when heads are firm and glossy
Onions
Indoor growing time prior to transplanting: 9 to 11 weeks
Germination time: 10-15 days
Seed planting depth: 3/8 inch
Temperature range for optimal germination: 65-80°F
Optimal growing temperatures** day: 60-70°F night: 45-55°F
Outdoor plant spacing: 12 inch
Days to maturity: 60-115
Cool-Season or Warm-Season Crop: Cool-season
Suited for plastic mulch and drip irrigation: yes
When to plant outdoors: 4 weeks before last frost
Harvesting characteristics: Green or bunching onion – when desired; bulb onion – when above-ground leaves fall, allow to cure 1-2 days, thinnings can be used anytime.
Celery
Indoor growing time prior to transplanting: 10 to 12 weeks
Germination time*: 21 days
Seed planting depth: 1/8 inch
Temperature range for optimal germination: 60-70°F
Optimal growing temperatures** day: 65-75°F night: 55-65°F
Outdoor plant spacing: 9-12 inch
Days to maturity: 110-120
Cool-Season or Warm-Season Crop: Cool/warm-season
Suited for plastic mulch and drip irrigation: yes
When to plant outdoors: after last frost
Harvesting characteristics: When outer petioles can be pulled anytime for immediate use, fully mature when about 3 inches by 21 inches.
Tomatoes
Indoor growing time prior to transplanting: 5 to 7 weeks
Germination time*: 7-10 days
Seed planting depth: 1/4 to 1/2 inch
Temperature range for optimal germination: 70-80°F
Optimal growing temperatures** day: 70-80°F night: 60-65°F
Outdoor plant spacing: 18-24 inch
Days to maturity: 52-90
Cool-Season or Warm-Season Crop: Warm-season
Suited for plastic mulch and drip irrigation: Yes
When to plant outdoors: After last frost
Harvesting characteristics: when evenly colored and firm
Peppers
Indoor growing time prior to transplanting: 6 to 8 weeks
Germination time*: 10-12 days
Seed planting depth: 1/4 to 1/2 inch
Temperature range for optimal germination: 75-85°F
Optimal growing temperatures** day: 70-80°F night: 60-70°F
Outdoor plant spacing: 18-24 inch
Days to maturity: 55-80
Cool-Season or Warm-Season Crop: Warm-season
Suited for plastic mulch and drip irrigation: Yes
When to plant outdoors: After last frost
Harvesting characteristics: When glossy in color and firm, either ‘green’ mature or final color maturity for the type and maturity.
Eggplant
Indoor growing time prior to transplanting: 7 to 9 weeks
Germination time*: 10-12 days
Seed planting depth: 1/4 to 1/2 inch
Temperature range for optimal germination: 75-90°F
Optimal growing temperatures** day: 70-80°F night: 65-70°F
Outdoor plant spacing: 24 inch
Days to maturity: 50-75
Cool-Season or Warm-Season Crop: Warm-season
Suited for plastic mulch and drip irrigation: Yes
When to plant outdoors: when night temperatures are above 50°F
Harvesting characteristics: When glossy in color and of satisfactory size for the cultivar and before seeds mature and darken.
Cucumber
Indoor growing time prior to transplanting: 3 to 4 weeks
Germination time*: 7-8 days
Seed planting depth: 3/4 to 1 inch
Temperature range for optimal germination: 75-95°F
Optimal growing temperatures** day: 70-90°F night: 60-70°F
Outdoor plant spacing: 12 inch
Days to maturity: 48-70
Cool-Season or Warm-Season Crop: Warm-season
Suited for plastic mulch and drip irrigation: Yes
When to plant outdoors: 1 week after last frost
Harvesting characteristics: When 3 – 4 inches long for pickling, 6-10 inches for slicing and fully green, yellow fruit should be discarded.
Muskmelon
Indoor growing time prior to transplanting: 3 to 4 weeks
Germination time*: 7 days
Seed planting depth: 3/4 to 1 inch
Temperature range for optimal germination: 75-95°F
Optimal growing temperatures** day: 70-90°F night: 60-70°F
Outdoor plant spacing: 12 inch
Days to maturity: 68-95
Cool-Season or Warm-Season Crop: Warm-season
Suited for plastic mulch and drip irrigation: Yes
When to plant outdoors: 1 week after last frost
Harvesting characteristics: When melon begins to detach from stem
Watermelon
Indoor growing time prior to transplanting: 3 to 4 weeks
Germination time*: 6-8 days
Seed planting depth: 3/4 to 1 inch
Temperature range for optimal germination: 75-95°F
Optimal growing temperatures** day: 70-90°F night: 60-70°F
Outdoor plant spacing: 18 inch
Days to maturity: 68-95
Cool-Season or Warm-Season Crop: Warm-season
Suited for plastic mulch and drip irrigation: Yes
When to plant outdoors: 1 week after last frost
Harvesting characteristics: When tendril nearest stem attachment turns brown and shrivels
Summer Squash
Indoor growing time prior to transplanting: 3 to 4 weeks
Germination time*: 7-10 days
Seed planting depth: 3/4 to 1 inch
Temperature range for optimal germination: 75-95°F
Optimal growing temperatures** day: 70-90°F night: 60-70°F
Outdoor plant spacing: 18 inch
Days to maturity: 42-65
Cool-Season or Warm-Season Crop: Warm-season
Suited for plastic mulch and drip irrigation: Yes
When to plant outdoors: 1 week after last frost
Harvesting characteristics: Zucchini, yellow and other elongate types when 5 to 8 inches long and skin is tender, skin must be very
tender on patty pan and round types and be 2 to 4 inches in diameter.
* Depends on temperature.
** Reduce day temperatures by 5 to 10 degrees F when the weather is cloudy.
*** In Pennsylvania the last frost is typically between May 1 and 25.
~ Direct seed about the same time you transplant for fall harvests.
This educational blog is a series of informative articles from the Penn State Master Gardeners volunteers plus news concerning the group and their activities. For more information, click here.
