Overwintering geranium plants

red-geraniums-in-a-window-boxThe first of three posts about geraniums — that most iconic midcentury flower — from Marybeth, a writer and avid gardener:

Hurry! Do you still have potted summer geraniums? If you have not had a heavy frost in your area, you can bring these half-hardy perennials inside to overwinter.  That is what our Mid Century Modest forebears would have done.  Overwintering geraniums is easy.  You have two options: (1) dormant style, in which your sleeping beauties are set out to be kissed into bloom next summer; and (2) houseplant style, with some winter bloom depending on your light conditions but always, the fat, padded, escalloped leaves to enjoy.  In either case, you will have plants for next year’s white window box or terra cotta porch pot.

We begin the same way for both options.  You need:

  1. clean scissors or garden shears
  2. balanced fertilizer (20-20-20) like Shultz or Miracle Gro (liquid is easier to deal with)For the houseplant option, you will also need:
  3. strong dishwashing soap like Dawn
  4. mister/spritzer atomizer/spray bottle

For both options: TRIM TO ONE THIRD.  Yes, even if you wince and the plant protests.  We are signalling to the plant that now is the time to return to roots and concentrate plant energy near the cuts.  Think of this also:  under the famine times of winter, the plant cannot support full growth anymore.

For the dormant option:

  1. After trimming to one third, take the root ball out of the pot.
  2. Gently, shake the soil free, reserving the soil.
  3. Return the soil to the pot, mixing carefully.  You want to make sure the soil has a uniform texture.
  4. Re-pot the plant in this “remixed” soil.
  5. Water lightly to remove all air pockets.
  6. Place the pot in a dark, cool spot; Between 60 and 45 is good, which means that you may want a cool basement, enclosed porch, or garage, depending on your climate zone.  Too cold, and the plant freezes.  Too warm? You may want to try the house plant option.

For the house plant option:

  1. Soak the plant with a good dose of water, letting the roots and soil soak.
  2. Lightly fertilize the plant as directed.
  3. Spritz the plant and soil surface with a misting of one part detergent to four parts water. Geraniums are prone to mites.  This soap treatment will help with this problem.
  4. Place the pots in a sunny window BUT NOT with direct southern, afternoon sun. Geraniums need light to bloom but not so much as to be sun stroked.  Think about your sun habits:  enough to enjoy and not enough to burn.
  5. Geraniums can be happy with periodic trying out of the soil.  I water moderately once a week, fertilizing once a month.
  6. If you get blooms, then toast the cheery lipstick-hued flowers by buying and wearing a matching hue!  If you do not have blooms, your light conditions are likely not right.  However, the leaves are lovely. And, you can delight in your thriftiness.  In the spring, you will be geranium-ready, without spending money.

Getting ready for spring:  in February or March, depending on your spring time, the houseplant geraniums will appreciate your continued care.  Put outside, as weather permits, during warm days, but bring inside at night.  If you do this for a week, then your plants will adjust to the harsher conditions of outside.  For the sleeping beauty plants, bring to a window in February and March and break dormancy by watering (weekly) and fertilizing (monthly).

Thank you, Marybeth! I didn’t put out any geraniums this summer, but I think that next year I will — so that I can overwinter them!

  1. Rufus Valentine says:

    I’ve had pretty good luck overwintering my geraniums using the dormant option. I fertilize them well through the growing season, and right around the time of the first frost, I cut them back a bit and bring them into the basement. I have a southwest corner with ample diffused light, where it’s never above 65 degrees. I don’t water them but one time in January. As soon as the daytime temps average in the mid-fifties, I bring them outdoors onto the south-facing deck, repot them in new, richer soil, hit them with a time-release fertilizer, water them thoroughly and regularly, and let them restart. Sometimes I have to prune them back a bit once the new growth begins. It’s nice to see something not go to waste.

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