Spring is almost here! Can you feel it?? It was in the 60’s this weekend and now I’m dreaming of the days when the garden will be lush with greenery and produce. We still have many cold days (and lots of cold nights) before that happens, but now is the time to start making your planting calendar. Next weekend is when I’ll start seeds indoors so it was time to come up with a clear plan on when things need to be planted!
Find Your Last Frost Date
The first step to making a planting calendar is to find your last frost date. Just google “last frost date” and you’ll come across many websites that will tell you the last frost date for your zip code. I used the one provided by Dave’s Garden. The date provided by most sites is the average day when there is a 50% chance that another frost could still occur. The actual last frost date will vary from year to year. Notice that two weeks after the 50% frost date, the likelihood of another frost has dropped down to 10%. This is why you’ll see that the transplant date for many plants is 1-2 weeks after the average last frost. I like to plan for my seedlings to be ready based on the 50% date and then I can always adjust as needed.
Look at Your Seed Packets
The back of your seed packets will tell you the information you need about when to start your seeds inside or when to sow them directly outside. Let’s look at an example:
For these tomatoes, I’m going to start them inside following the “When to start inside” instructions on the packet. It says to start them 4-6 weeks before transplanting, and transplanting is 1-2 weeks after the average last frost date. I want to know when to plant based on the last frost date, so I use the earliest transplant time available (one week after frost date) and subtract the maximum grow time (6 weeks). This means a seed starting date of 5 weeks before the last frost. Repeat this process for everything you’re planting. If a seed packet doesn’t have planting information, Google the full name of the plant for instructions. In this case I would search for “San Marzano Tomato Seeds.” Usually the sites selling the seeds will provide planting instructions.
Use Google Sheets or Excel to Make a Planting Calendar
The easiest and quickest way to make a planting calendar is to use a spreadsheet tool like Google Sheets (free with a Google account) or Excel.
Organize your plants
I separate my plants into two chunks–the ones I’m starting indoors and the ones I’m planting outside from seed (direct sow). The first column has the names of the plants. The second column has the quantity of containers for the ones I’m starting inside. That let’s me maximize how many I can fit on my heat mat and under my grow lights.
Figure out the right weeks
Look at the second row of the spreadsheet. It shows a negative number, positive number, or “LF” in each column. LF stands for last frost. The numbers to the left are the weeks before the last frost, and the numbers to the right are weeks after the last frost. For example, -5 means five weeks before the average last frost date. Extend the numbers to the left to accommodate the earliest indoor start date and extend the numbers to the right to accommodate the latest transplant or direct sow date. Each year, I then fill in the exact dates in the first row above the numbers. I only work on planting on Saturdays, so these are the 2020 Saturday dates that most closely align with the last frost date.
Color-code the calendar
For the plants I start indoors, the first dark green square indicates the weekend I should plant the seed. The light green shows the indoor growing time. Then the second dark green square shows when it needs to be transplanted outside. If there’s a range given, like 1-2 weeks after the last frost date, then I shade both those weeks dark green.
For the direct sow seeds, the dark green squares are when I need to plant outside. I take the same approach if there’s a range. For plants that need to be planted multiple times to stagger the harvest, I add an asterisk (*) next to the plant name, shade all the planting weeks, and then add more detailed notes in the note column on the right.
Reuse the Calendar
When you make your own planting calendar, it’s easy to reuse it from year to year! Next year, I can just change the Saturday dates at the top and I’ll be ready to go. Keep track of anything that didn’t work well and make adjustments the next year if needed. For example, if your tomato plants weren’t quite as big as you wanted them to be when you transplanted them, then start a week earlier next year.
I hope this tutorial helps you make a planting calendar that’s perfect for your garden! Having a planting calendar makes it so much easier to remember what needs to be planted when and ensure your garden gets off to a great start.
