Gardening With Gardening:  Seed Starting – Create a Calendar

Gardening With Gardening: Seed Starting – Create a Calendar

There’s a certain quiet that comes after the holidays. The decorations will soon be put away, and storage totes about as it suddenly becomes time to organize. We flip the calendar to a new year. One of the best tools for organizing yourself before seed-starting season begins is actually a calendar. A calendar, combined with a spreadsheet, can act as your to-do list. This is a great time to create one – the holiday rush is over, but the ground is frozen and we can’t do much outside. The best part? Once you collect all of this information, you can use it each year!


Frost Date

First, when is your average last frost date? If you aren’t sure, check here. Write that down! For me it’s sometime between the first and second week of May, depending on what Mother Nature decides to throw at us. In 2021, we still had snow on the ground in late April, but it was long gone and warm out before Easter in 2020. 

Using a calendar that has week numbers – where each week is numbered for the year, from 1 through 52  – can make it easier for you to count back weeks when trying to figure out which week is “6-8 weeks before last frost.” You can turn this on in Google calendar under Settings – General – View Options, or you can print out a calendar like this one. For example, Saturday May 7th is the end of Week 18. This also happens to be Mother’s Day weekend, a common reference date for when to plant in my area.

Growing Information

Next, find the growing information for each plant. I gather all of my seed packets (for those I have already), or open up the information about a particular plant on a website or catalog (Botanical Interests, Johnny’s, etc). If you happen to have seed catalogs, Johnny’s includes all of the important info about each plant (vegetables, herbs, flowers) in their catalog. You can request their catalog here, and they also have a digital version you can flip through.


You can write out a list, but I find it most helpful to do this in a spreadsheet on my computer. I use a Google Sheet, so that it’s easy to access on my phone and I can have it with me all of the time. (This master list sometimes helps keep me from buying seeds I already have!) The spreadsheet also lets me sort things by “date to cold start” or “date to sow,” and then create a to-do list in my calendar. You can also search within it using Ctrl + F to find something you’re wondering about – “Do I start Larkspur outside or inside?”


In my spreadsheet, I have the name of each plant, and columns for:

  • Annual or Perennial
  • Veggie or Flower
  • Direct sow outside or start indoors? (I use “in or out” in my column to keep it simple.)
  • How many weeks before the last frost do the seeds need to be planted?
  • Date to sow
  • Does it need cold stratification? (I either insert the weeks needed, or write no.)
  • Date to cold start (See info below about calculating this.)
  • Sowing Depth (on the surface, ⅛”, ¼”)
  • Sun (full sun, part shade, shade)
  • Mature height (This helps me plan which things to plant next to one another, to make sure I can reach them all and don’t shade anything out.)
  • Notes (Does this flower reseed itself? Do I have a specific place I want to plant it?)


You could also add columns for:

  • Days to Germination
  • Temperature for Germination (Does it need to be on a heat mat? Johnny’s catalog has details on ideal temperatures for germination. If your space is cooler, consider a heat mat.)
  • Whether plants need netting or support (I put this info in some of my notes.)


If you’re planning for cut flowers, you might want information like: 

  • Number of Days to Bloom
  • First Bloom Date (You’d calculate this by adding the days to bloom to the seed sowing date)
  • When to harvest? (Recommendations for when to cut the flower for best vase life, such as when the bud just starts to crack open. Johnny’s has this.)

About Cold Stratification

This was mentioned a bit in a post last year, but cold stratification is a process that attempts to mimic mother nature. Some seeds might fall to the ground in the autumn and then be exposed to cold winter temperatures and the freeze-thaw cycle that happens in spring. Cold stratifying is as simple as popping your seed packet in the refrigerator, or sprinkling seeds on a moistened paper towel that you place inside a zip-top bag in the fridge for a few weeks. When preparing your calendar, keep in mind that this time will need to be factored in. You’ll count back from last frost using the recommended sowing date, then back again for cold stratification.

For example, if I use May 7th as my last frost date, and have a plant whose seeds should be started 8 weeks before last frost, but they also need 4 weeks of cold stratification, I need to pop those seeds in my fridge in mid February! 

Additional Notes

Some flowers and veggies can tolerate cool temperatures (some even down into the teens!) and can be planted outside before your last frost. These are aptly referred to as “cool flowers” and include flowers like snapdragons, poppies, bachelor buttons, and rudbeckia. Lisa Mason Ziegler has written a book on the topic. She is a flower farmer down in Virginia (very different growing conditions than my upstate New York world) and runs Gardeners Workshop Farm. Her website has seeds (flowers AND veggies) that are organized into “cool” pages, so you can get information on what might work where you are. She also has lots of information on growing these types of plants.

Take some time, pop on a good podcast or playlist, and start entering all of your seed info into a calendar. When you have the “date to sow” for everything, take one extra step and organize your seed packets by date. You’ll be glad you did, and save yourself the extra stress when March comes and it seems it’s time to sow everything! Starting now will also help you plan out what materials you might need to gather, to be discussed in the next post!

Start with My Seed Starting Calendar:

Bonus! I’m sharing my seed starting calendar. You can see how busy I’ll be! To adapt this for your location, just save a copy of it and update the last frost date at the top. The dates will automatically be calculated from there. If you add a new plant type, just make sure to carry the formulas into your new row.