FOR RELEASE THE WEEK OF APRIL 29, 2001:
Our sprinkler system has been set up to irrigate our lawn every day. I understand that we don't need to water a lawn as often if we water more deeply. Can we just start watering twice a week or do we need to "transition" our lawn into the new system?
You'll need a transition period of about a month, says Howard Neibling, University of Idaho extension water management engineer. If you've been applying daily, shallow irrigations in the past, the roots of your turf are likely to be shallow as well. They'll need to deepen before you can switch to twice-a-week intervals.
"Start early in the spring while it's cool and try to water down to about 18 inches," he says. The easiest way to tell how deep the water is moving is to try to push a narrow rod into the soil. "If the soil is moist, the rod goes in. If you can't push it in, it's dry."
Deeper-rooted turf is healthier than shallow-rooted turf, Neibling says. It can draw nutrients from a much larger mass of soil.
An inch-and-a-half of water is a rough estimate of what you'll need to apply every three or four days on a well-established lawn. Adjust the amount as the lawn's water needs change with the season. "Too many people have the timing set to meet the lawn's mid-season water needs and they irrigate all season as though it were the first of July."
My raspberries were a little stunted and weak last year. This spring, some of the canes are wilted. When I cut into a lower cane, I found an inch-long white worm with a brown head. What is this?
It sounds like a raspberry crown borer, the very damaging larva of a clear-winged moth that probably laid its eggs on your raspberry's lower leaves last summer, says Bob Stoltz, University of Idaho extension entomologist. If you noticed stunting and weakness last year, there's a good chance you're already in the second year of your infestation.
Unfortunately, crown borers can destroy your raspberry plantings in a few years, says Stoltz. "First you'll have smaller and smaller canes. Then the borers will take out your whole stand."
The standard treatment is a diazinon drench, applied about a foot above the ground from October through March. "You need to do it two years in a row," Stoltz says. "If that doesn't keep up with the damage, then take the raspberries out for two years."
Between now and October, he advises that you keep your raspberries fertilized and watered and in as good of a shape as you can to help them tolerate the infestation.
Why do some "recipes" for potting mixes recommend adding one-third "garden soil" to a third peat moss and a third perlite? What is the purpose of the garden soil? My garden soil is a heavy clay and I doubt it would do my potted plants much good.
The intended purpose of the garden soil is to add a full complement of nutrients, which soil-less components like bark, peat moss and compost may lack, says Bob Tripepi, University of Idaho horticulture professor. Garden soil also fills the pore spaces between the components of the soil-less mix, causing the mix to hold more water and less air. Unfortunately, if the water leaves too little room for air, the situation can be detrimental for root growth.
Unless your garden soil is a near-ideal loam, Tripepi advises you to leave it out of your pots. Instead, use a carefully "constructed" commercial potting mix, made with an appropriate amount of coarse materials like bark and fine materials like peat moss, sawdust, compost or composted biosolids. Some mixes also add sand for weight.
"A good potting mix bought from a store should be formulated so that all of the components mixed together will enable the mix to have good aeration, drainage and water-holding capacity," Tripepi says. "For those reasons, few commercial potting mixes contain soil. In addition, soil can contain weed seeds, insects and organisms that cause plant diseases, so it should always be pasteurized before it's mixed in with the other components."
Once you've planted your containers, be sure to follow fertilizer recommendations on the potting mix package, fertilizer product bag or plant stakes.
Why don't the huge soda pops our kids order at fast-food places cut down their appetites?
You're right in thinking that they should, says Martha Raidl, University of Idaho extension nutrition specialist. Indeed, the average teen consumes 15 to 20 teaspoons of added sugar each day from soft drinks alone.
However, soft drinks appear to be less filling than food, so people tend to eat a normal-sized meal even if they've consumed a lot of sugar from soft drinks.
A study in the February issue of the medical journal Lancet confirmed many parents' concerns: children who increased their intake of sugary soft drinks were more likely to become obese.
Encourage your children to drink milk instead, says Raidl. "When soft drinks replace milk, most individuals will not be able to get enough calcium in their diet."
[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 Cooperative Extension System or imply approval to the exclusion of other suitable products or firms.]