Henry Homeyer: mid-winter care for your houseplants

By Henry Homeyer
©2020 Telegraph Publishing LLC

Are you suffering from the mid-winter blahs? More importantly, are your houseplants? We can’t be in our gardens outside now – except for a few stalwarts who are pruning, I suppose – but we can take good care of our houseplants.

Although I have not the passion for houseplants that I do for plants outdoors, my friends seem to think it is all right to dump tired or depressed houseplants on me. I mean they gift me houseplants that need a little extra care. This winter I ended up with around 50 houseplants including: a banana tree, cacti of various sorts, a gardenia, and much, much more. That’s fine. I will re-gift some in the spring or summer, and move the rest outdoors.

One of the best things you can do for your houseplants is to be judicious in watering. More is not better! Roots will rot, especially if the soil mix has gotten compacted over the years (as organic matter has been depleted).

That said, as February transitions to March, the sun is stronger than it was in January, and the plants are waking up for spring. Their roots are growing and seeking moisture. Instead of watering once a week, twice a week is better for some. Leaves are growing and need more water.

Rosemary plants, which do well in dry climates like California or the Mediterranean coast, do not survive if their roots become totally dry. Outdoors there, their roots go down deep to a soil layer that is slightly moist all year. But in a pot, it’s easy to let them dry out.

If you see the leaves start to wilt, water immediately! Sadly, if you miss a watering and the plant is in a sunny window, your plant may die. And then, no matter how much you water your dead rosemary, it will not come back to life. I know, I’ve tried. Just harvest the leaves and use them in the kitchen,

I keep a woodstove chugging along day and night, all winter. I keep a kettle on it to add a little moisture to the air, but that is not nearly enough to keep most houseplants happy. The best thing you can do if you have a warm, dry house, is to buy a humidifier. This will make you more comfortable, too.

I have a small humidifier in the bedroom that will deliver a gallon of water to the air in 12 hours, but that is a drop in the bucket for an entire house. So I also have a cabinet-style humidifier that will deliver 5 gallons of water to the house in 12 hours. It wicks up water and then blows air over the wick to evaporate it. Since I have an open-plan home, this helps throughout the downstairs. Still, it is a struggle to keep the house at 40% relative humidity, my goal. It would be easier to do if I kept it running 24/7, but I don’t like the sound of the fan all day, and mainly run it at night. I fill the humidifier with a watering can from the garden that I fill in the bathtub.

Last fall Cindy asked if I knew a greenhouse that would keep a client’s gardenia for the winter. She said she’d been told they were fussy, needed high humidity and were aphid-prone. I asked one greenhouse, and was told $5,000 would be about right for caring for one for 4 or 5 months. Huh. So I decided to do it – for free, and for the challenge of it.

The gardenia was loaded with flower buds when it came to the house in October. So far, we have had 2 flowers blossom, but most dried up and fell off. Still, getting any blossoms is a victory – I think.

So here’s how I did it: I’d like to say it is aphid-free because I washed the leaves and growing medium carefully before bringing it in the house. That’s what I would recommend. But life was busy, and it’s a 4-foot tall tree in a 50-pound pot, so I just lugged it in – frost was predicted.

I carried it upstairs to our cool, sunny laundry room. I filled a 12-inch plant saucer with small stones, and kept the saucer full of water. The gardenia sat on the stones and breathed in the evaporated moisture. I also sprayed the gardenia with a special plant misting device made by Florasol. This sprays a very fine spray with an easy squeeze, and is the best of the sprayers I’ve tried.

Still, it was not happy. Buds dried and dropped. I moved it into a bathroom where the shower is used twice a day, morning and evening. Everyone was asked to spray anytime they were in the bathroom. But there was not enough sunshine, and still no blossoms opening up.

Finally I hauled it back down the spiral staircase (losing buds along the way) and set it next to my desk and computer, the warmest place in the house. I set up that big humidifier nearby, and keep the hand sprayer handy. It is in a bright, west-facing window, and is in flower now. And no signs of aphids!

In March I will start to help some dormant plants to wake up. I’ve had a fig tree and a crape myrtle in pots in our dark basement at 40 degrees all winter. They’ve dropped all leaves, and I only water them every 6 weeks or so, and lightly. But I will bring them up into the house, and give them a taste of liquid fertilizer – just a light dilution. I like Neptune’s Harvest fish and seaweed formula. That worked fine last winter.

So keep an eye on your houseplants, and if they get dusty, you can take one in the shower with you and give it a good spray. And that should give your husband or wife a good giggle, too.

Henry is the author of 4 gardening books, including Organic Gardening (not just) in the Northeast, which was recently re-printed and is now available directly from him.