Just an update (from 7/28/2020) from the state office regarding Master Gardener Volunteer Activity:

As always, please feel free to send questions and concerns to Mikaela: mboley@umd.edu. 

Written by Janet Mackey- Talbot Co. Master Gardener
Photo Credit: J. Mackey

As summer turns to autumn, you may face the situation of having some combination of seedlings, plugs, small plants, big plants, and woody plants in pots. Yes … in pots. Not in the ground where they could take care of themselves this winter.

There are good reasons why those plants are still hanging out with you on the patio. Some plants may not look strong enough yet to survive in a garden spot. Some may require more time or energy than you have to get them into proper places in the garden. No matter what the circumstances, if your nursery area looks like my patio nursery did in the middle of September, you need to get thinking about taking care of these plants before it gets cold!

I rely on multiple approaches to deal with pots of plants that I haven’t yet planted when cold weather closes in. Perhaps some of these ideas will help you, if you find a plant or two (or a dozen) languishing in your back yard in pots. All of my suggestions have some merit, but I have to admit that I made up the first item on my list. Need I add that it is untested?

1. Stop adding plants. Don’t buy new plants, don’t accept pots from friend, and don’t dig up perennials that need dividing until you have plans in place for your existing inventory. (Yeah. Right.)
2. Give plants away to other gardeners. This one I rely on quite a bit. Our Master Gardener “Socially-Distanced Plant Swap” spreadsheet has been a good way for me to find folks who might like a dozen pots of little bluestem or blue mistflower that were banished from my sunny bed when they did not play well with others. Last summer, my back steps served as a staging area for plants heading to new homes.I have found that trading plants with gardening friends can be a type of insurance policy. When a favorite plant does not reappear, it’s good to know that somebody nearby may be growing its offspring and might offer it back to me.
3. Plant them!! To a casual gardener, this might seem like an obvious answer. But those of you who propagate plants – growing them from seed, rooting cuttings, or even dividing a plant when it really isn’t big enough to be divided – surely can feel my pain. The little plants just don’t bulk up as fast as we might have imagined in June. Now the little plants face a moment of reckoning. They are unlikely to survive sitting in a pot exposed to freeze-thaw cycles throughout the winter. So even if I have to plant them in a cluster in a temporary spot and move them next growing season, I try to find them a spot somewhere in my garden. Little plants are more likely to survive with their roots deep in the soil than frozen in a pot.
4. Let them grow through the winter in pots in a protected spot. There are a variety of permutations of this approach, but they all involve trying to minimize crazy swings in temperature while giving plants access to sunlight and occasional water.

If you have cold frames, you can tuck the pots below ground level, surrounded by bricks that will soak up the winter sun, and covered with clear plastic panels that can be removed on nice days. If you are not blessed with cold frames, you can bury pots to the soil line in an empty garden bed. I use both my raised bed and an area behind my garage. Last winter I mounded some compost and mulch (to make it easy to dig holes for the pots) and overwintered my “forest” of young holly trees provided by a couple different gardening friends. The extra time in the pots allowed the trees to bulk up their roots before getting planted this spring. And, I’ll be honest, some of those pots are still there hoping I take my own advice and try #3. Plant Them before the next winter rolls in.

When I find myself with unplanted plugs or small plants at the end of summer, I try to pot them up into at least a quart-sized pot before burying the pots. That way they will have sufficient soil to hold moisture and nutrients as their roots grow through the winter and they will be ready to take off in the spring.
The 2020 gardening season has had its challenges. No wonder you might have little plants still hanging around rather than growing in proper beds. Perhaps one of my tips might help you get them settled in for winter, and together you and they can try again with the 2021 gardening season.