Outdoor edibles slow down growth in November

Outdoor potted lettuce

Saturday, November 14, 2020

If you have noticed that plants stop growing in the winter, whether indoors or out, you would be right.  It is not just the temperatures that affect this slow down.  It is the amount of sunlight!  

Basically, plants go dormant when receiving less than 10 hours of daylight.  For my latitude, this is from November 21-January 18.  You can look on the weather channel to see when your daylight hits 10 hours.

When planting in the fall for winter crops, you need to plan that they are at full, harvestable size by the time daylight hours are less than 10 hours.  For me, this is November 21st (I add 14 days to the days to harvest on seed packets to be on the safe side for the cooler temps and less daylight than in spring).  They will remain basically this size until the end of January and daylight hours exceed 10 hours again, when they begin regrowing.  If growing in a greenhouse, the warmer temperatures will help plants grow, but at a much slower rate than during longer daylight times.  

The same techniques for protecting spring crops work for your fall and winter gardens.  
Protect your new plants from a late frost
Preparing for a hard freeze

Extend the season with protection for plants

This year, I used portable greenhouse covers over my potted cool season crops and added gallon jugs of water in any empty space.  The water jugs will help to moderate the temperatures inside the greenhouses, keeping them warmer at night.  The number one cause of plant death in a greenhouse is get scalded.  It can easily get up over 100 degrees inside a closed up greenhouse on a sunny day in the 50's.  The greenhouses do have flaps that can be opened when needed.  I keep them open in the fall until the temperatures are pretty steady in the 40's with night time temperatures in the 20's.

Lettuce and greens in January under a portable green house

Growth starts back up at the end of January, for indoor and outdoor plants.  The lettuce, chard, sorrel, cabbage, kale, celery, and herbs that have overwintered will start growing with vigor again after this time with clear days and warmer temperatures.  Cool season crop seeds, like spinach, that were scattered or sown in the fall will begin to sprout; their inner clock just knows when it is time to get going again.

Winter edible garden

Covering plants with row covers or portable greenhouses can help your plants grow; warmth does make a difference.  Just don’t expect significant growth until we get back to at least 10 hours of sunlight.