What your (L)atitude Determines

Your latitude determines how long your growing season is.

Now, why is that important?

You are going to have to wait 28 days from the time you plant a radish seed to get to eat a radish.  Spinach takes about 45 days before you can pick it.  If you are hungry for watermelon, you will have to wait at least 80-90 days, and more likely 100-110 days.  You have to wait for the ground to be warm before you can even plant the seeds.

It is very important that you understand how long your season is and how much time you have left to grow your watermelon.  Timing is everything.

So how do you figure this out?

I’m going to tell you!

First you need to hunt down your last expected spring frost date.  The long standing tradition is to check the good Old Farmer’s Almanac.  You can also check another almanac, Farmer’s Almanac.

I had a hard time finding one link for the National Weather Service, but you can poke around and probably find some more accurate information there.

This will take you to a page that lists the last date for spring frost for your state.  Just click on your state and it will list several large cities.  It also lists the first date for autumn frost for your state  The difference between the two gives you an idea of how long your growing season will be.

I put in my zip code in Missouri and the Old Farmer’s Almanac shows this:

TRUMAN DAM & RSVR, MO Apr 19 Oct 19 182 days

I’m going to estimate my first fall frost as 10/30 and my last spring frost as 4/19.

This last spring frost date seems a little off to me.  I have completely lost my first planting of tomatos to a hard frost on May 2nd.  So I will probably wait past April 19 to put in my warm loving seeds.  You just have to guess depending on what your weather is doing each year.

Based on my records, if I wait and plant after May 2,  I still have plenty of time to grow watermelons, or popcorn, or just about any regular vegetable.

Now for places farther north, like where my mom was from, White Bear Lake, Minnesota.  It lists St. Paul frost dates:

ST PAUL, MN May 5 Oct 2 149 days

Last and first frost dates are 30% probability. Calculated using 1981-2010 Climate No

If you live there, you have to give your soil a little longer to warm up, which means you are going to be rushing to get 100 or 110 days out of your growing season.  You will have to plan very well and look for shorter season varieties to make sure you can sink your teeth in a juicy watermelon of your own making!

Calculating planting dates for Fall planting.

Now, if you want to plant a fall crop of lettuce or spinach, all you need is your first fall frost date.  Count back from that to know when is a good time to think about planting.

For Missouri, I would use 10/30 and count back 45 days.  That puts me about the middle of September.  That sounds about right.  It is finally starting to cool down some then.

If it looks like it will frost closer to the estimated date of 10/19, I can protect my plants on the cool nights by covering with a sheet or some frost fabric.  That will help me extend my harvest into the first part of November.  I know most nights are still warm enough not to freeze those cold hardy crops.

Would you like a worksheet to help you figure out where you are in the growing season and what you have time to plant now?  Sign up for my newsletter below to get the perfect worksheet!




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