If you didn’t dig a fancy new garden bed last fall, but you still hope to plant asparagus this spring, all is not lost. “It’s OK to plant in the spring and it’s also OK to plant in the fall,” says Rose Hembrook, co-owner of Andy’s Asparagus Acres. “In the fall, you want to wait until it cools off. In the spring, you want to wait until the spring is actually coming on.”
Hembrook is based in Tennessee. Her family has been growing asparagus from seed since 1932. “They’re very slow to grow,” she notes. “By the time a root is 1 year old, [the plant is] almost like a hair—it’s really thin and really small.”
It takes three years before the roots of those asparagus seedlings finally will produce viable, harvest-ready spears. As such, purchasing asparagus roots or “crowns” is more practical—especially if you hope to harvest fresh spears anytime soon.
Some nurseries sell 1-, 2- and 3-year-old asparagus crowns. Older crowns usually cost more, but you should be able to harvest sooner. “Three-year plants are usually about ready,” Hembrook says. “They’re an edible size. You can harvest from a two-year [crown], but it’s not going to be fully mature.”
She continues, “A one-year [crown] is a good investment. A lot of people are reluctant, but you’ll be saving money. And, in a couple of years, they’re going to be ready. So, just put them in the back of your garden and let them grow.”
Types to Try
If you’ve never grown asparagus before, you might want to start with just 10 to 25 crowns in your garden. Also, because some varieties will perform better in your particular microclimate than others, you should try more than one. Once you know which varieties work best for you—and which you prefer to eat!—you can add more plants next year.
Mary Washington, Jersey Giant, Jersey Supreme and Purple Passion are among the most common asparagus varieties available. An old-fashioned type, Mary Washington is a prolific producer that can tolerate both extreme cold and heat. And, while Jersey Giant is best-suited for growing in hotter climates, Jersey Supreme handles colder weather well.
For its part, Purple Passion sends up deep purple spears that turn bright green during cooking. It’s also said to contain more sugars than other asparagus types.
Whether you opt for an heirloom variety or the latest hybrid, most asparagus plants thrive in nutrient-rich, well-draining garden soil. “You want a sandy, loam soil that has some good depth to it—at least 12 inches,” Hembrook says. “The roots like to grow deep into the soil.”
They also like moisture levels to be just right. “After you get everything in your planting bed the way you want it, do a [percolation] test,” Hembrook advises. “You make a hole, fill it up with water, and time it to see how long it takes the water to dissipate. If the water washes away too fast, the plants are going to get wet, but they’re not going to get any nutrients. And, if the water sits there a long time, it’s going to cause the roots to rot.
“You want an even flow of water, and all the water should be dissipated within two hours or so.”
Hembrook also recommends maintaining a pH level between 6.8 and 7.1 in your asparagus garden bed. (And if you’ll regularly be adding compost—or watering with compost tea? Plan to test the pH every couple of weeks.)
Once your asparagus bed is ready to plant, place crowns about 18 inches apart and 6 to 12 inches deep. Also, be sure you orient your crowns properly. “[The roots] shouldn’t spread out like an umbrella in your hand,” Hembrook cautions.
“Hold it by the crown and it should just hang straight down. It will have a little wave to it, but it shouldn’t spread out like an umbrella. If it does that, it’s upside-down.”
Once your plants begin to take off, keep an eye out for asparagus beetles and other pests. To attract beneficial insects like lady beetles, flower flies and assassin bugs, plant marigolds nearby.
Hembrook adds, “You can plant garlic in between your asparagus to keep the bugs out. The smell doesn’t go into the [asparagus] spears. Rabbits and squirrels don’t like it either.”
Watering is one other important aspect of care. “One common mistake people do is they plant their asparagus and then every day they’re out there watering it,” Hembrook says. “But if the [asparagus] ferns turn yellow, that’s a good indication that they’re watering too much.”
When you do water, use rain or pond water if you’re able. And, to help prevent fungal disease, water at ground level, rather than sprinkling water on the foliage itself.