FOR RELEASE THE WEEK OF JAN. 25 1999:
My lawn had patches of bur buttercup last summer. It looks like it’s coming back already. Should I treat it now or wait?
Bur buttercup is becoming a signal that spring is right around the corner, says University of Idaho extension weed scientist Don Morishita. A winter annual, its emergence is often triggered by the first warm spell in January or February. As soon as daytime temperatures climb into the 45 to 50-degree range, you’ll start seeing small, gray-green, tap-rooted plants with three to four deeply lobed, fine-haired leaves resembling antlers.
The trick to controlling bur buttercup is to nail it before it flowers and drops seed. In its late-winter seedling stage, it’s susceptible to foliar-applied herbicides like glyphosate (Roundup), glufosinate (Finale or Liberty), 2,4-D or trimec. If you’d rather not spray, Morishita says digging works, too.
In early spring, bur buttercup sends up narrow-leaved stems tipped by solitary, yellowed-petaled flowers. By mid-spring, it forms solid, 3- to 4-inch-tall mats. By early summer, it scatters its seed and its burs have turned from green to straw-colored to brown.
Last year’s plants won’t be back this year, but their seed is raring to grow now and those mats will keep spreading if you let it, Morishita says. A word to the wise.
What are gnats doing in our house in the dead of winter? How do we get rid of them?
If what you’ve got are slender, fragile, grayish flies no longer than 1/8th of an inch, they’re fungus gnats. According to Bob Stoltz, University of Idaho extension entomologist, they feed on decaying organic matter in your houseplants’ potting soil. Other than being truly annoying by flitting around our noses and eyes, they’re no threat to us or to the plants. Stoltz suggests several approaches: 1) tolerate them, 2) keep the potting soil a little bit drier, 3) treat your houseplants with the biological control agent Bti, 4) apply parasitic, beneficial nematodes, or 5) use an insecticide labeled specifically for houseplant soils.
By the way, if those bugs aren’t slender or fragile but instead are fat-bodied and wide-winged, with wings widening towards the back, what you’ve got are trickling filter flies, Stoltz says. They develop in sink traps if your water is dripping and buzz around your tubs and sinks.
We’d like to put in a vegetable bed this year. How much sunlight will it need?
The more, the better, says University of Idaho extension horticulturist Michael Colt. Six to eight hours of direct sunlight daily is the very minimum. "The prime garden area is where the vegetables will receive full sun throughout the day," Colt says. Lots of sunshine is particularly important for fruit-forming vegetables like tomatoes, cucumbers, squash, eggplants, peppers and melons. Many leafy vegetables–like spinach and lettuce–will grow well with less than full sunlight.
Not only can nearby trees and shrubs shade your vegetables, but they can also rob them of much-needed nutrients and water. In selecting a garden site, Colt says you’ll also want to avoid low, flat areas where water collects; soils in these areas will be slow to dry out and warm up in the spring.
Rather than buying seed-starting mixes, can I make my own?
You can, says University of Idaho horticulturist Bob Tripepi. Commercial mixes are usually free of weeds, diseases and insects, offer improved drainage and are certainly more convenient, but determined gardeners can mix and successfully pasteurize their own soil medium. Start with equal parts of garden soil, sphagnum peat moss and sand, then sift out any lumps.
Next, destroy the soil organism that causes damping-off, which rots so many seedlings before or shortly after they emerge. Thoroughly moisten–but do not drench–the mix, cover it with aluminum foil, then heat it on your outside grill for 30 minutes at temperatures of 140-160 degrees Fahrenheit. (Take his word for it, Tripepi says: this process stinks too much to be done indoors.) Verify the temperature with a meat thermometer, and don’t let the mix get too hot: while the soil won’t burn, the peat moss will.