My Everchanging Garden

Gardening That Grows With Me

Planting and Sowing Calendar 2024

In my working life I was an accountant so it’s no surprise that I use an Excel spreadsheet to calculate when to start seeds indoors. It’s similar to many automatic seed-starting charts across the web, although I’ve customized my spreadsheet for what works in my garden. My plan allows me to work off my expected last frost date but with some adjustments based on the vagaries of our Ontario spring weather. I use this seed-starting excel calendar for vegetables, annuals, perennials and herbs. It’s a list of what to plant, how much and when.

snapshot of excel spreadsheet with seed starting calendar

What’s changed for this year:

  • starting tomatoes one week later
  • starting cosmos two weeks later, testing some via winter sowing
  • starting annual salvia one week later
  • starting zinnia one week later, testing some via winter sowing
  • starting gomphrena two weeks later
  • starting angelonia one week later
  • trying some perennials from seed for the first time, varying some start times to see what is best.

I will also try the winter sow method for zinnias, cosmos and marigolds. Again, I don’t know about start dates, so I’ll pick some dates two to three weeks before my regular indoor sowing and compare the results.

For 2024, here is my seed starting and sowing plan by week:

Week of Seeds to start
January 15 Starts: lisianthus, balloon flower, echinacea, perennial salvia
January 29 Starts: pansy
February 12 Starts: foxglove
February 19 Starts: rosemary (unless I do cuttings)
February 26 Starts: onions, begonia, euphorbia, heliotrope, annual salvia, primrose (cold strategy 2 weeks)
March 4 Starts:
March 11 Starts: celery, parsley, alternanthera, dichondra, dusty miller, lavender, kirigami, verbena
Start watching lisianthus to plant out in garden
March 18 Starts: cabbage, kale, lettuce, swiss chard, lobelia, angelonia
March 25 Starts: ageratum, alyssum, agastache, gomphrena, primrose (out of fridge)
April 1 Starts: basil, peas, tomatoes, second lettuce, marigold, ornamental pepper, dahlia
April 8 Starts: cosmos, helichrysum
April 22 Starts: zinnia
Direct sow: beets
April 29 Starts: dill
Direct sow: carrots
May 6 Starts: cucumbers, squash, zucchini
May 13 Plant: potatoes
May 20 Direct sow: Beans
Jun 3 Direct sow: second cucumber
Jun 10 Direct sow: second beans
June 24 Direct sow: second beets
Starts: Flowering Kale
Jul 1 Direct sow: third beans, second zucchini
Jul 22 Direct sow: fourth beans, fall peas
Aug 26 Direct sow: spinach in the cold frame

The above is based on a last frost date of May 13 but assumes warm season crops and annuals will not be planted out until after the May 24 weekend. Most seed packages for tender plants say to plant out after all danger of frost has passed. Many seed calendars use your last frost date for this calculation. The problem is we frequently get a severe cold snap long past mid-May, even if it doesn’t officially bring frost. So warm season crops should not go in the ground for at least two weeks past the last frost date to avoid having cold weather set them back. You can check the weather forecast all you want, but it’s rarely accurate two weeks out. I have learned the hard way to wait. So I’ve added a column to my spreadsheet (plant weeks pre-frost) that allows me to work seed starting times from when I actually plan to transplant to the garden rather than one static date and keep adjusting this time based on experience.

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