When we talk about getting an early start on your planting we often reference the last frost date. This is the day in which we no longer expect the temperature to drop below freezing. The problem with this recommendation is that weather is rather unpredictable to any degree of certainty, so this recommendation is made with very local and very rough guesses in mind. Let’s look at what it means and then show you some places where you can get that date for yourself.
How To Look Up Last Frost Dates
There are website all over the place that allow you to put in your zip code and get a huge amount of weather data that you can use. Personally, we like to use Dave’s Garden for this information, but most any site you find in Google will give you roughly the same data. By simply putting in your zip code you’ll get an average day of first and last frost as well as a chart with historical information pertaining to the likelihood of any given day passing a certain temperature point.
This is a great thing to have, but there’s more to the information that picking a date and running with it!
Using Last Frost Dates
Last frost dates are a guess, an educated guess, but still a guess. When you get your frost dates you need to remember that they are historical and not necessarily reflective of actual weather trends for the year.
As an example, for our area we expect the last frost to be sometime around May 10th. We can be fairly certain that we will have frost until April 25th and we can be fairly certain we won’t have frost after May 25th. That’s three dates for us to work around! If we want to be extra extra safe we can plant our plants that need to avoid frost after the 25th of May, but that limits our growing season a bit. If we want to be extremely risky we can plant our crops after April 25th, which may result in some losses if we get a frost.
So how do you choose which date to go with?
Well, we look at the weather of course. The weather is almost never right, but you should be able to get a 1 week forecast that is roughly accurate. You can also look at the past weeks actual temperatures to see if your night time temperatures are still dipping into freezing temperatures. With this information in hand you can make a better guess and choose when to plant your frost susceptible plants.
Make a Spreadsheet
We encourage everyone who is gardening to make a spreadsheet for their garden. If you’re not super tech savvy, don’t worry, it doesn’t have to be complicated. We just use Google Sheets and we drop in the plants we are going to grow in one column and then all the information about the plants we need in the others. This can be as detailed or light as you want, but for what we’re talking about now, you should figure out when each plant you’re growing is recommended to be planted.
Recommendations might range from several weeks before the last frost right up to after danger of last frost, so knowing the expected date of the last frost which we found online helps us identify when we should plant our plants. Once we have the expected date we mark the calculated date for each of our crops. From our example, if the planting date is 2 weeks before the last frost and our last frost is estimated to be May 10th, then the planting date would be April 27th.
Now the next step here is to check your temperatures and not just follow your sheet blindly. If the weather is colder than expected, be sure to push your planting back a bit aligning the temperature of the previous week with the historical estimates. This can take a little doing, but we just re-crunch these numbers at the end of every week leading up to our planting season.
Starters and Backups
We grow more starters than we intend to use. It’s easy, doesn’t really cost much, and can save you in a pickle. If all our crops die from an unseasonable frost, then we have backups ready and waiting to go in the ground. If our crops survive just fine we give away our backup plants to friends and neighbors. If we have more than we can giveaway we sometimes pot these and grow them inside and other times we send them to the compost to be reused next year as dirt.
No matter how you slice it, you are way safer if you grow a handful of extra starters than you are without doing so.
Staggered Planting
As an aside, if you’ve calculated when you’re planting your plants for the last frost, it’s also really easy to figure out your staggered planting schedule right after. For us we simply look at growing time and harvest times and figure out how much we want to harvest at what intervals. Then we map out the space and add the dates in their own columns to maximize our harvests and minimize our unused soil. This can take a bit of math, but that math is well worth it!
Plan For Your Frost Dates
While you can certainly wing it if you’re planting a garden, you run the risk of failure without checking the dates of your last frost. Without this critical data you may lose your plants by planting too early, or limit your harvests by planting too late. Checking frost dates can seem intimidating at first, but with a simple spreadsheet and very simple math, you can ensure a safer season of planting with better yields throughout the year.
Happy Homesteading!