Fielding Questions: Caring for houseplants while on vacation, weed control in lawns, when to prune geraniums

This week, gardening columnist Don Kinzler fields questions about the best time to apply weed control, when to trim back geraniums wintering in the basement, and more.

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Reader Michelle V. grouped her plants together, watered them, and covered them with light construction plastic while gone on vacation. She writes that her plants were still moist and healthy when she returned over two weeks later.
Contributed / Michelle V.

Q: I cut this idea out of your column some time ago and tried it when I went on vacation. I’m very pleased with how well it worked. After two-and-a-half weeks, the pots were still moist and I know they would have been fine for three weeks and maybe even more. Thanks to Susan who wrote in with the idea, and thanks, Don, for publishing it. - Michelle V.

Houseplants on vacation (3) Feb. 18, 2023.jpg
Reader Michelle V. shares a column clipping about caring for houseplants while on vacation she says worked well.
Contributed / Michelle V.

A: I’m happy it worked out well, Michelle. She goes on to describe the method, “I made sure the pots were well soaked and drained, then I lowered the heat to about 63 degrees and closed the blinds. Then I draped plastic over, sealed the seams with clothes pins, and tucked the plastic under to seal well. The poinsettia was the only plant that was a little unhappy, with a few yellow leaves that dropped.”

Keeping houseplants happy while on vacation is a challenge for many of us, and this method works well. Thanks Michelle and Susan, and as I always say, we’re all in this together.

Q: When is the best time to apply weed control on a lawn. – Cecil and Marlene S.

A: Weed control depends, of course, on what type of weeds are in the lawn. The most common category of lawn weeds most homeowners battle are broadleaf weeds, such as dandelion, plantain, creeping Charlie and many others, as opposed to grass-type weeds


Although do-it-yourself granular weed-and-feed products are heavily advertised, they often aren't as effective as hoped. The ingredients in nearly all weed-and-feed products don't prevent weeds from starting, instead their mode of action only kills weeds that are already actively growing.

Application is also tricky. The granules must land and stick to the leaves of weeds, which is why the instructions usually say to apply when the lawn is wet or dewy.

Most lawns aren't a carpet of weeds, so applying herbicide over the entire lawn can be a costly waste and contribute to herbicides ending up in rivers and lakes.

A more effective option for lawn weed control is liquid lawn herbicide that is spot-sprayed onto weeds, which are usually randomly scattered. These products also aren’t preventatives, but must be applied to weeds that are already growing.

Mid-to-late May is generally a good time to apply lawn herbicides. Weeds must be actively growing. For hard-to-kill perennial weeds like creeping Charlie, September is the recommended time, as we approach fall, with a follow-up application in May.

Q: I’m growing geraniums under lights in the basement. They’ve grown very well, and are getting quite large. Is there a preferred time to trim them back? – Alan S.

A: There are two times that I trim back the geraniums that we’re wintering in the basement under lights. The first time is right away after I remove the geraniums from their outdoor planters in preparation for bringing indoors. I cut the large summer plants back to two or three inches above soil level, pot them up, and put under fluorescent lights in the basement.

The second time to trim them is about March 1, cutting the plants back by at least one-half of their winter growth. This encourages fresh, bushy growth to form, and the plants will be perfect for transplanting outdoors again in mid-to-late May.


If you have a gardening or lawn care question, email Don Kinzler, NDSU Extension-Cass County, at . Questions with broad appeal may be published, so please include your name, city and state for appropriate advice.

Don Kinzler, a lifelong gardener, is the horticulturist with North Dakota State University Extension for Cass County. Readers can reach him at
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