I've grown just about everything in my suburban backyard garden, but I've always avoided asparagus because of its finicky reputation. Heavy feeder. Touchy about soil pH and temperature. Years waiting for the first crop. Inevitable death by fungus. There's a reason asparagus is so expensive!
But thanks to Carl J. Cantaluppi, there's an asparagus bed in my spring garden this year. The agricultural extension agent in North Carolina's Granville and Person Counties, Carl is one of the leading asparagus experts in the u.s. He's known as the "dean" of "Asparagus School," a program he founded for commercial growers.
"A lot of people get scared because they think asparagus is hard to grow, but it's not," he assures me.
That's good, because it's one of the healthiest and tastiest veggies: A 5-ounce serving provides 60 percent of your daily needs for folic acid, a B vitamin linked to lower risk of birth defects and heart disease. It's a good source of fiber, low in calories (20 per serving) and contains glutathione, a powerful cancer-fighting antioxidant. And the taste of the first crisp green spear in April...well, there was a reason the Roman emperors kept a special fleet of ships for fetching the first spring asparagus.
How to Grow
Unless you're a purist, forget seeds. Caring for the tiny seedlings is a part-time job. Instead, buy year-old, disease-free crowns from a reputable grower.
The plants come in male and female varieties. The traditional female types -- Mary and Martha Washington -- have given way to new male hybrids, such as Jersey Giant, Jersey Prince, Jersey Knight, Syn 53, Syn 4-362, UC 157 and Viking KBC. These male plants outyield old female varieties by as much as 3 to 1. Another advantage to the all-male bed: The sprigs stay green until the first frost, allowing more time for photosynthesis or more food for next year's crop!
Asparagus requires lots of space. Crowns should be planted every foot or so in rows 4 to 5 feet apart. "This delays the onset of fungus disease that comes up in late summer or early fall," Carl explains.
Fungal infection can be a problem. Asparagus beds may succumb to either asparagus rust or Cercospora needle blight. Regular applications of a fungicide labeled for use on asparagus for these diseases can help in areas with ongoing disease problems.
And yes, when it comes to soil, asparagus is a bit of a fusspot. It likes a sweet (alkaline), well-drained soil in full sun. One thing you don't want to do...plant it before the soil temperature has warmed up to 50°F unless the crowns are dormant.
It won't grow at all in some places, like Florida, where it's too warm and wet for it to go into a necessary dormancy period. On the other hand, it's drought-tolerant and grows almost while you're watching it. Your first spears will emerge about a week after you plant the crowns.
How to Harvest
Though they look luscious, don't harvest any asparagus spears the first year you plant, or you'll exhaust the food supply in the crowns. Be patient and wait till year two, then harvest judiciously. Carl recommends picking spears for only 2 weeks that first spring after the planting year. Your patience and willpower will help your crowns produce even more spears in subsequent years. As the weather warms up, you may be picking twice a day.
Gardeners are commonly advised to cut back asparagus in fall to reduce fungal risk, but according to Carl's research, that doesn't work. In fact, allowing the ferns to remain in the beds lowers the soil temperature, reducing the risk of frost damage in spring, and helps catch snow for additional moisture.
Once you pick it, it's quite easy to put asparagus to use in the kitchen (see recipes for Asparagus Vinaigrette and Sunny Asparagus Tart). Store spears upright in a jar with about an inch of water in the bottom. Before cooking, break off the woody ends by hand or cut them with a knife. Asparagus can be steamed, boiled, sauteed, blanched, even roasted (with some olive oil and balsamic vinaigrette) -- just don't cook it down to mush. You'll lose the bright green color, most of the nutrients and that fresh, crisp snap. Enjoy!
A spear is ready to harvest when it's about the diameter of a pencil or larger, and roughly 8 inches tall.
Depending on thickness, you can steam or microwave asparagus for 5 to 8 minutes for the perfect crisp-tender texture.
Store asparagus the way you treat cut flowers -- upright in a container filled with at least an inch of water.