Desert Blooms

Southwest Yard & Garden by Dr. Marisa Thompson Compost Spent Coffee Grounds Before Using Them on Your Soil The pH of my morning cup of coffee (not the grounds) while still black (left) and after adding cream and honey (center), and plain filtered tap water (right). Photo credits M. Thompson.   Question: Can I discard spent coffee grounds in my houseplant pots?                                    -        T. Dominguez, Santa Fe   Answer: Sure you can, but I can't exactly recommend it. Putting the grounds directly on houseplant soil might not pose a problem, but it’s hard to be sure. Research on the composition and chemistry of coffee grounds has shown wide variability. Some of this variability stems from differences between species in the Coffea genus grown for commercial production—most commonly either Coffea arabica or Coffea canephora (syn. C. robusta ). And then there are many varieties and cultivars too. Plus, th

  Southwest Yard & Garden by Dr. Marisa Thompson, with the help of Dr. Carol Sutherland! Dwarf umbrella tree (Schefflera arboricola) looks great from afar, but on closer inspection, mealybugs are an issue. Photo credit Tyra Trumble. Question: Can I put peroxide in the soil to kill the mealybugs on our schefflera?                                            -Tyra T., Los Lunas Answer: I don’t recommend it. While hydrogen peroxide is not likely to kill your huge houseplant, it’s not going to kill your mealybugs either. Full disclosure to readers: I worked with Tyra over the summer, and we’ve been discussing ways to handle these mealybugs since she discovered them on her mom’s 12-foot-tall, 20-year-old dwarf umbrella tree ( Schefflera arboricola ) in May. At first Tyra reported that leaves were dropping, and she suspected powdery mildew. On closer inspection, we were able to identify the white flecks and cottony clumps as evidence of a dreaded but all-too-common houseplant pest