Garden Dilemmas, Delights & Discoveries, Ask Mary Stone, New Jersey Garden blog

Overwintering Potted Gardens

a Mother Earth Face Pot with bangs of Japanese Forest Grass

Hello fellow readers, With the recent below-freezing temperatures, my garden ghost routine of covering pots with sheets to keep them from freezing has begun. Admittedly it’s silly as acceptance that the growing season is over will eventually set in; about when I grow weary of the ritual or when the ghosts are more in view than the plants left in hiding.

Garden Ghosts

Potted gardens have become more than annuals; many include perennials and even small shrubs to kick them up a notch. Mary’ hug-a-tree’ feels guilty for letting plants that can come back die in their pots, but letting them go is okay. Our annuals are perennials in warmer zones, so what are we supposed to do, save the world? Sound convincing? I’m not buying it, and neither is Ron from Bangor, PA, who asked how to overwinter his pots. I’ll bet Ron has ghosts, too (smile).

Concrete, glazed, or terracotta pots with or without plants will crack if left out in the winter, except for the fancy schmancy ones made to withstand old man winter. Generally, fiberglass, polyethylene, or structural foam pots can remain outside. While insulating, even plants that are suitable in our zone will suffer from the freezing and thawing of roots if left unprotected. Some say that two zones hardier (zone 3 plants in zone 5, for instance) may overwinter just fine. Still, plants can be easily killed if water accumulates and freezes, so be sure they drain well.

You can plant the pots themselves (if freeze tolerant) in a holding spot dug in the soil to the top of the pot until next year. Or gather them against the north or east side of your home and cover them with a foot of shredded leaves or straw. Containers moved into an unheated building such as a garage or shed where temperatures remain slightly above freezing is ideal, especially for breakable terracotta.

a golden retriever looking over pots Ovewintering in a garage

Regardless of your technique, roots must never dry out, so keep plants moist until the first hard freeze and check the soil whenever the temperature rises above 40°F. Lastly, allowing your plants to go dormant is essential before putting them to rest. So maybe my garden ghosts aren’t so silly after all? Boo!

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Column updated 10/26/22

Mary Stone, owner of Stone Associates Landscape Design & Consulting. As a Landscape Designer, I am grateful for the joy of helping others beautify their surroundings which often leads to sharing encouragement and life experiences. These relationships inspired my weekly column published in THE PRESS, 'Garden Dilemmas? Ask Mary', began in 2012. I dream of growing the evolving community of readers into an interactive forum to share encouragement and support in Garden and Personal Recoveries - seeking nature’s inspirations, stimulating growth, weeding undesirables, embracing the unexpected. Thank you for visiting! Mary

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