NOTE: All member and nonmember tickets must be reserved in advance, and masks are strongly recommended for all guests and required for unvaccinated guests ages 2 and up. Learn more about how you can join us!

Western PA Calendar for Starting Seeds
Mar 21

Western PA Calendar for Starting Seeds

By Charity Grimes Bauman

Timing can be criticall when starting seeds at home. Too early and you'll have overgrown and poorly nourished plants waiting to get outside. Too late, and you;ll miss valuable growing time. Use the calendar below to determine when to start seeds indoors.  For details on the supplies you need to get started and step-by-step directions for starting seeds, see our post on Indoor Seed Starting.

When to start seeds inside is calculated backwards from the time it is safe to plant the seedlings outdoors.  This is determined by the last frost date, which varies by plant hardiness zones.  Pittsburgh is USDA Plant Hardiness Zone 6, so the average last frost date in spring is around May 15, and first frost date in fall is around October 15. 

The dates listed below are for earliest harvests, but many can also be planted or re-planted later in the season.  Some varieties can also be direct-sown, unless indicated. 

*Usually direct-sown, but can be started indoors.

**Must be started indoors; the outdoor growing season isn’t long enough for fruit production.


This is very useful, thank you! I wish you have a longer list including green beans and garlic and another list for flowers

By Diana on May 2, 2018

Could we have a longer list including more vegetables, herbs, and frequently planted flowers.

By Kelliann on Mar 26, 2019

Garlic can, and should, be planted in the fall. It will overwinter in the ground and come up in the spring. Planting in the fall gives the garlic a head start on putting down roots and establishing itself. (If you didn’t plant it in the fall, you can still plant in the spring)

By Tracee on May 6, 2019

Is it too late to start tomatoes from seed?  Green beans and peppers?

By Vicki on May 1, 2020

Green beans are fast growing and quick to harvest. You sow directly in the garden when the soil has warmed and the danger of frost has passed. Sow a new row weekly for a few weeks to have successive crops of beans for harvest.

By Lara on Feb 17, 2021