FOR RELEASE THE WEEK OF JULY 15, 2001:
I have a hard time getting my children to eat vegetables. One of the few vegetables they like is iceberg lettuce, but the only way they will eat it is as a garnish on their hamburgers or tacos. Any suggestions on how to improve their intake of vegetables?
Slip in a little raw spinach in place of the lettuce, says Martha Raidl, University of Idaho Extension nutrition specialist. That will give them more vitamin C, vitamin A and folic acid for every green leaf they eat. Researchers at the University of Arkansas found that tasters couldn't tell the difference between lettuce and spinach garnishes, except that the spinach garnishes gave their hamburgers and tacos a crunchier texture.
While watering my houseplants, I noticed tiny white bugs on them that leave a "cotton-like" substance in their wake. What are they and what should I do about them?
Bob Stoltz, University of Idaho Extension entomologist, thanks our reader for sending her bugs. As he suspected, they're mealybugs, a common houseplant pest.
"Pick them off, wash them with soapy water or apply a registered houseplant insecticide with a Q-tip" is Stoltz's advice. Insecticidal soaps and systemics will also work, as will a ladybug called--what else?--the "mealybug destroyer." If you're interested in experimenting with other biocontrol agents, Stoltz suggests trying lacewing larvae or several of the parasites that are on the market.
Should I fertilize my large shade trees or are they fine on their own?
Even large trees can benefit from occasional fertilization, says Dan Barney, University of Idaho Extension horticulturist. It's time to fertilize when you notice yellowish or poorly colored leaves, slow growth and weak or spindly shoots. Otherwise, put your tree on a 3- to 5-year fertilization schedule.
Buy a fertilizer that contains both nitrogen and phosphorus or one that includes nitrogen, phosphorus and potassium. Because nitrogen is the nutrient Idaho soils most commonly need, it's best to base your fertilizer applications on it. Barney advises applying 3 to 6 ounces of nitrogen for every 100 square feet of planting area. Determine the approximate planting area by multiplying the length and width of the tree's spread.
Fertilizers are labeled with numbers that indicate the percentages of three or four nutrients. Nitrogen is always listed first. To find out how much to apply for every 100 square feet, divide the amount of nitrogen you want to add by the percentage of nitrogen in the fertilizer. For example, if you want to apply 4 ounces of nitrogen and the fertilizer you've purchased is 16-10-10, divide 4 by 0.16. That means you should apply 25 ounces or--considering that there are 16 ounces per pound--about 1 1/2 pounds of fertilizer. If you're covering a 20-by-20 foot area, or 400 square feet, you'll need 6 pounds of fertilizer (1 1/2 times 4).
Now that you know how much fertilizer you'll be applying, punch or dig 1- to 2-inch diameter holes--12 inches deep and at least 2 feet apart--in concentric circles around your tree. Start about 3 feet from the trunk and move out to a few feet beyond the dripline or crown. Count the holes, divide the amount of fertilizer you'll be applying by the number of holes, then pour it in. Fill the holes to within 2 inches of the soil surface and top them off with topsoil, sand, compost or peat moss. "Then sit back and relax for another 3 to 5 years," Barney says.
By the way, he says: Never use weed-and-feed products to fertilize your tree. They contain herbicides--not what you want your tree to eat.
For more information on fertilizing large and small landscape trees and shrubs, pick up a copy of the University of Idaho publication "Fertilizing Landscape Trees" from your county Extension office. Or, call Connie King of UI Ag Publications at (208) 885-7982, fax her at (208) 885-4648, send e-mail to cking@uidaho.edu, click on web site http://info.ag.uidaho.edu, or post a letter to Ag Publications Building, University of Idaho, Moscow, ID 83844-2240. Cost to Idaho residents is $1.55, including tax and shipping.
[READERS: Do you have a question about your home, yard or garden? Send it to HomeWise, University of Idaho Ag Communications, Moscow, ID 83844-2332 or e-mail it to homewise@uidaho.edu. Mention of proprietary products or firms does not constitute endorsement by the University of Idaho Extension or imply approval to the exclusion of other suitable products or firms.]