Ask the Gardener: Christmas cactus, gnats, shredded leaves and more

Gardening editor Doug Oster gets asked a lot of questions. A lot. And he doesn’t mind offering gardening advice. But rather than just limiting those answers to the person who asked, we thought it might be a good idea to share that wealth of knowledge with everybody.

There are three ways to send in your questions:

Email askdoug@535mediallc.com
Submit your question on our “Your Garden” section of our site
Send us a message on Facebook.

(The questions may be lightly edited for grammar/clarity/etc.)

Christmas cactus

Question 1: Christmas cactus

Lynn: I need more info on a Christmas cactus. They have gotten brown on the edges, and it looks kind of like they dried out or are dying. What should I do? And can they be transplanted? (My windowsills are kind of cold though.)

Doug: It’s pretty easy to grow, but should be treated more like a houseplant than a cactus. I keep mine in the windowsill on the dry side, but not completely dried out. They bloom when they are ready, sometimes becoming Easter or Thanksgiving cacti.

The good news is, they like it a little cold. The first step is to pick up the pot. Is it super light, or heavy? If it’s light, it needs a little water; if heavy, let it dry out. They transplant easily if you want to start over. Get a good planting mix from your local nursery. Get it moist, but not dripping and then make the move to a pot that’s one size bigger than the container it’s in.

Dead is dead, anything that doesn’t look to be alive should be removed from the Christmas cactus.

Question 2: Gnats on plants

Becky: I am still getting gnats in my house, I’m thinking from my potted plants from outside even though I repotted them. I have tried the usual vinegar, sugar, Dawn soap in white dishes around the house, and I used paper cones with this mixture, too. I also am going to try a hydrogen peroxide and water mixture on my plants. I’m at my wit’s end. Can you suggest anything else?

Doug: You need to let the soil dry out. If it’s too wet, the gnats will persist. The fungus gnats will disappear once it dries out.