Sunday, March 6, 2011
Overwintered potted plants
I overwinter a lot of plants- some in my attic under supplemental florescent light, some on a kitchen windowsill and others in my garage. These garage plants are a little sturdier than the ones I over winter inside, plus they usually cannot stand the dry conditions inside a house (I once read that to provide indoor air moisture equal to outdoors, you would have to mist inside plants a hundred times per day). Another reason to overwinter in my garage is when the plant is dormant and needs just a little extra cold-weather TLC. Potted plants are especially vulnerable to the freeze-thaw cycle (which also cracks ceramic or clay pots). The roots of potted plants are essentially above the ground and can freeze badly and dry out easily if left outdoors all winter. Going into an unheated garage or shed can provide enough added protection to allow the plant to survive.
If you overwinter pots this way you may encounter the same problem I have- the potted plant seems to break dormancy early in these sheltered conditions. This is a problem- these plants cannot adequately photosynthesize in the dark conditions in my garage nor will they come into proper bloom. I don't want to set them outside without protection: after all, they were protected from the harsh, outdoor conditions all winter. So, this is what I do- I mass the plants in pots near the house and cover them with pine straw (I tuck pine straw under, between, behind and over the top of the pots-see photo above). The house provides a wind break and some heat pools. This protects the plants and pots, allows rain and some warmth from the sun, and it conditions the plants to the outdoors. If the plant is truly early, this may slow its growth down just enough. Some people put potted plants in a cold frame- my cold frame is too small for the 15-20 large pots I have (even if it hadn't gotten loose from its rope and stake mooring in a windstorm and flew up 10 feet and broke apart!) You can also trench your potted plants- that is, put them in a trench and cover with straw, hay or leaves for a month or so, until it warms up- perch them on brick for drainage. In a month, your plants will be truly ready for spring...as will we all!