Garden Giving You the Cold Shoulder? Shoulder Seasons Explained and Explored

Summer has officially kicked off, and of course you are probably familiar with all four seasons: spring, summer, fall, and winter.

But what about the spaces in between these main seasons? Do they have a name or purpose in the garden?

That they do! The period of time in between the peak of each season is called a shoulder season. Mostly this is in reference to the period of time when there is still a risk of frost but the temperature is rising between winter and spring. As well as the reverse for that period of time when plants are still growing but frost is imminent in that summer/fall or fall/winter depending on your growing zone. 

Shoulder seasons 101

Shoulder seasons are an excellent way to extend your growing season so you are not waiting for your final frost date in spring, or your first frost date in fall.

So what does this actually look like? Well, the first step is for you to determine when your frost dates are. You can look them up on your local extension office’s website. With that important information in hand, you can then start to figure out how much you can push your season based on those dates.

The next thing to keep in mind is the Persephone Period. The Persephone Period is the time of the year when there is less than 10 hours of sunlight each day. Plants require at least 10 hours of sunlight to actively grow. Less than that and they may put out a new leaf every week or two, but that’s about it. The bulk of their energy goes into staying alive. 

Depending on your growing zone and just how cold it gets in your area in the winter, you may need to employ some season extension techniques to protect your plants from extreme temperatures. This will also depend on how mature the plants are and just how hardy they are too.

For example, my almost mature crop of Bloomsdale spinach survived multiple nights in the teens, hard frosts, snow flurries, and all around fairly cold temperatures without any protection. On the other hand, my Swiss chard, kale, and beets that were planted at the same time died with the first hard, unprotected freeze. They were too immature to handle the extreme temperature and are just not as hardy as the Bloomsdale spinach. 

So choosing the right plants, the right varieties, and the right level of maturity are important considerations for growing in the shoulder seasons. When looking in seed catalogs, most will let you know if the specific variety can handle extremely cold temperatures or not.

The best bet: Biennials and hardy annuals

Typically biennials and hardy annuals are great candidates for growing in the shoulder seasons. 

Biennials are plants that get established in the first year, then flower in their second year. Think carrots and foxgloves.

Hardy annuals are plants that prefer cooler temperatures for getting established, then flower once it gets warm. Like broccoli, cauliflower, snapdragons, and larkspur.

Biennials will require less cold protection than hardy annuals since they are designed to survive the cold so they can reproduce the following year. They do best getting established in the late summer when there is still enough sunlight for them to bulk up and establish a nice healthy root system to carry them through winter.

For hardy annuals, if you get them established (and keep them cool!) in mid to late summer, they can produce in the fall. This timing is a bit more tricky since if you get them in too early they won’t be able to handle the heat. If you get them in too late though, there won’t be enough sunlight for them to produce before winter and you’ll have to keep them protected until they are able to produce in early spring. If you can get the timing right, or if you get them in too late, you still have production in a shoulder season and that’s a win! 

Cold shoulder

With that, there are different types of frost blankets that will help insulate your plants and keep the frost from forming on their leaves.

Different weight blankets are rated for different temperatures and will typically only raise the temperature underneath by a few degrees. So don’t mistake me and think you can plant tomatoes in February and just cover them with a few blankets! With frost blankets, the plants can still receive frost damage wherever the blanket is in contact with them. To prevent any damage, make sure the blanket is raised up off of the leaves, or that there are multiple layers of blankets.

Cold frames, low hoops, greenhouses, and caterpillar tunnels are all forms of semi-permanent to fully permanent structures that you can grow in that will increase the temperature and keep frost and snow off of your babies. A nice thick layer of mulch will also help insulate the roots and protect them from extreme temperature swings. Mulch will also help keep the roots moist which will help protect the plants. The water will freeze around the roots, helping to maintain a temperature of 32°F. 

Water is a great tool in your season extension tool box because of this insulation power. In the Fall when there is a threat of light frost, you can actually spray down your frost tender plants with water and keep them safe for a little while longer. This technique won’t work for a hard freeze on tender plants, but if your forecast has a light freeze followed by another few weeks of warm temperatures, why not help keep your dahlias and tomatoes chugging along just a bit longer? 

Final thoughts

Experiment with planting dates, plant types, and covering techniques so see how much you can grow when all your main season plants are still just little seedlings or spent for the season.

And a fun fact about growing veggies in the fall and early spring: plants convert starches into sugars to act as their natural antifreeze so they taste so much sweeter than their warm season/unfrosted counterparts!


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