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Seed Starting Schedule for Summer Flowers

by | Feb 6, 2022

This is the general guide that I follow to start my warm-season tender annuals. We certainly tweak it from time to time and don’t always stick to it, but this gets us up and going. This is all based on the last expected spring frost date. In my 8a winter hardiness zone southeastern Virginia garden, mid-April is my last expected historic frost date.

Notes that can affect starting and growing:

  • I start most of my seeds in the small soil blocker, occasionally in plug trays, I noted which below. Soil-blocked plants tend to grow quicker. My starting times have 1/3 of the time cut off of the recommended conventional methods timelines.
  • The first spring planting of warm-season tender annuals are planted into beds that have the mulch film Bio360 with the black side up. This offers a tad of soil warming and gets them off to a great start.
  • When I plant warm-season tender annuals into cooler conditions than I should, I cover the beds with hoops and row covers.
  • I plant 3-5″ tall transplants.
  • I do not do any flower direct seeding in spring or summer, all seeds started indoors.
  • The number of succession plantings depends on the length of your growing season.

4 weeks before my last spring frost I start:

Zinnia and tomato seedlings in 3/4″ blocks on their way to a demonstration. This is 40 plants on a 5′ x 7″ reuseable tray.


2-3 weeks before my last spring frost I start:

A cafeteria tray with 240 – 4 week old Ageratum transplants in 3/4″ soil blocks.

I hope this helps!

Lisa Lisa Mason Ziegler founder of The Gardener’s Workshop and Flower Farming School Online. Award-winning Author of Vegetables Love Flowers, and Cool Flowers. Watch Lisa’s Story and view her blog Field & Garden. Connect with Lisa on Facebook and Instagram!