Freeze Dates

• The last frost of spring is a pivotal event when it comes to vegetable planting. Many vegetables cannot be planted until all danger of frost has passed. In southeast Pennsylvania, the warmest part of the state, the last frost is usually around April 15. But in the coldest parts of northwest Pennsylvania, frosts can occur into June.
  
  

Transplant Timing

• Hardy vegetables like cabbage, cauliflower, broccoli and onions can be planted in the garden four weeks before the last frost. Celery, peppers and tomatoes should not be planted until after the last frost, and cucumbers, watermelon, summer squash and muskmelon should be planted at least one week after the last frost.
  
  

Growing Indoors

• Many vegetables grow best if you plant them in containers indoors before transplanting them to the garden. Allow six to eight weeks of indoor growing for tomatoes and cauliflower, eight to 10 weeks for peppers, two to three weeks for squash and cucumbers, six to seven weeks for cabbage and broccoli, and nine to 12 weeks for celery and onions.