Days to Maturity
The colder than usual days we’ve experienced lately is a not so subtle reminder of where we live. Combined with our
short growing season and hardiness zone 3-4, it’s safe to say we’re in the cold climate zone, which I admit, is a no
brainer.
What this means to northern gardeners, however, is that we need to be particularly careful of our seed and plant
selection. In my last column (Evening News, Sunday edition, 2-16-03) I talked about matching hardiness zones and
corresponding plants rated to that zone. In this column I’d like to talk about an equally important cold climate
consideration, especially for vegetable gardeners: days to maturity.
Most vegetable seeds you purchase lists the days to maturity on the seed packet. This usually ranges between 45
days (think beans and radishes) to over 100 days (Atlantic Dill Pumpkins). In our short season zone, we need to be
diligent about reading this information on the seed packet if we want the bragging rights to a red ripe tomato or melt-
in-your-mouth watermelon.
Unfortunately, many well-intentioned gardeners choose seeds for their favorite vegetable without carefully scrutinizing
the seed packet for this information. The result is lots of green tomatoes (you can only eat so many fried green
tomatoes!) and/or pumpkins that rot on the vine before ever turning orange. Eventually, they throw up their arms and
say it’s impossible to grow anything in this cold climate. Okay, it’s true most of us will never grow a cantaloupe the size
of a basketball, but there is no reason we can’t grow just about anything here in the north country.
Days to maturity refers to the number of good growing days needed to produce a ripe vegetable. To make this
determination, you first need to know how many frost-free days there are in your area. This can vary from one
location to another, even here in the E.U.P. In general, there are fewer frost-free days in low, inland areas than in
areas with greater elevation or that are in close proximity to large bodies of water. For instance, in the book, A Sierra
Club Naturalist’s Guide to the North Woods, it lists Houghton as having 148 frost-free days, compared to only 65 in
Watersmeet in the western Upper Peninsula.
I don’t have an official estimate of frost- free days in the Sault Ste. Marie, area. However, I believe it to be somewhere
between 85 and 90 days. Unfortunately, of these 85-90 days, only about 70 (or less) of these days are good growing
days. That is, where daytime temperatures top 70 degrees and nights stay above 50 degrees. Thus, it would be
prudent to purchase seeds that state “70 days to maturity,” or less. Fortunately, there are seed companies that cater
to us cold climate gardeners and have developed hybrid varieties of vegetables that will ripen in 65-70 days.
Over the years, I’ve discovered many tested varieties of vegetables, such as Early Girl Tomatoes, Sugar Baby
Watermelon and Northern Extra Sweet Corn, that not only ripen in less than 70 days of good growing weather, but
tastes darn good!
Now, having stated the above, it is possible, and often desirable to grow varieties of vegetables that require over 70
good growing days to ripen. Things like acorn squash and cantaloupe take up to 85 days to fully mature. You can
even grow those 200 pound Atlantic Dill pumpkins that require over 100 days to maturity!
So how is it done? By “extending the season,” which I’ll talk about in my next column. If you have any questions or
comments please feel free to email me at moranneil@hotmail.com.
Happy Gardening.
Potential MSU Master Gardeners, don’t miss out on the Spring 2003 certification program. These classes don’t come
to the area very often. They start up in March in Chippewa, Schoolcraft, Mackinac and Luce counties. The ten-week
course includes classes on Plant Science, Integrated Pest Management and Flower Gardening. I’m looking forward to
teaching the vegetable gardening class. For more information call the MSU Extension office at 635-6368.
Here’s a list of companies that offer a good selection of short season vegetables:
Vesey’s Seeds Ltd.
Prince Edward Island
York, Z9Z 9Z9 Canada
902-368-7333
J.W. Jung Seed Co.
335 S. High St.
Randolph, WI 53956
920-326-3121
Gurney’s Seed & Nursery Co.
P.O. Box 4178
Greendale, IN 47025-4178
www.gurneys.com