This week's sudden temperature dips served as a reminder that the summer garden party will be coming to an end soon enough.
As we move into a fall, an upcoming forecast will have vegetable gardeners scrambling to pick their last tomatoes and peppers and hunker down for fall.
Except that hunkering isn't really necessary. Some planting can mean fresh greens into December even if you don't have a greenhouse or cold frames.
"A fall garden is really bountiful," says Niki Hayden, who founded the Boulder Culinary Gardeners.
She describes herself as a "low-tech gardener," meaning that she relies on the occasional use of row cover weighted down with rocks to protect on bitter cold nights. Otherwise, though, she takes advantage of the natural hardiness of greens such as spinach, lettuce and arugula to carry her through the cooling temperatures.
"We tend to have more rain at this time of year than in mid-summer when it's so dry," she says. "Greens grow beautifully. We have fewer pests. It's much easier to have a beautiful greens garden."
Roland Evans, who lives up Fourmile Canyon and saw two of his three greenhouses severely damaged in the fire, says he already has the remaining greenhouse planted. At 7,400 feet, where he lives, such protection is necessary with temperatures that dip below freezing occurring earlier in the season than in lower elevations.
However, he says the principle for figuring out what to plant in the fall is the same at all altitudes.
"Pretend it's spring. That's the secret," he says. "You start planting all your early spring vegetables."
There are a few caveats. Long-maturing spring-planted vegetables such as cauliflower won't have enough time to mature before the coldest weather strikes, but Evans says you can plant sprouting broccoli.
Many greens thrive in cool weather; spinach, for example, along with lettuces, needs cooler temperatures to germinate. (Evans "tricks" his spinach seeds by placing them in the freezer before planting.)
Brassicas such as collard greens or kale even taste better after a frost, the dip in temperatures causes the plant to produce sugar as a natural defense, making the greens taste sweeter.
Evans says he has planted Japanese greens, some of which are hardy to 0 degrees. In general, he advises, more bitter greens tend to be hardier.
He uses cold frames with layers of protection. While some seeds may go dormant, they will come back in early February, he says.
"You get a very early crop."
Many gardeners plant spinach in this way with the intent of letting it "winter over," so that tender leaves grace their salad bowls in late February and early March.
The trick at lower elevations can be keeping temperatures cool enough to get seeds to germinate and keeping tender plants cool on the odd 80 plus-degree day that might punctuate cooler weather.
For this, Hayden uses row covers on the seed beds and young plants and keeps them moist.
She plants her seeds in rows, which is the best way to plant in a large garden, so that you won't step in planting areas and compress soil. For gardeners with raised beds or a long single row, sprinkling the tiny greens seeds can be a great and simple way to plant. Mix the seeds with some dry compost or soil, using lots of seeds, and sprinkle over a thoroughly watered garden bed. Cover with row cover and keep moist. As greens come up, thin plants, using the baby leaves in salads. After thinning, let larger plants mature, cutting off larger leaves as needed.
Hayden, who has grown as many as 23 types of lettuces in a season, says the sturdier types such as batavians and romaines are good for winter planting, although mesclun mixes also work well. She also generally plants about five varieties of spinach, and arugula, one of her favorite greens.
Kale, collards, turnip and mustard greens also do well.
When a bitter freeze and/or snow threaten, Hayden covers the plants with two layers of row cover and a plastic sheet weighted down with rocks.
"When it warms up the next week, you have saved the plants for another two to three weeks.
"The last week of December is a killer," she says. "That's my demarcation."
Evans, with his greenhouse and cold frames can take plants through the winter.
In addition to greens, he also plants some root vegetables such as carrots, beets and celeriac and covers them with mulch.
"You can pull them right through the winter," he says.