One of the earliest spring crops also requires the most patience. If you aren’t growing asparagus yet, start preparing a spot this season to be ready to plant next year.
Asparagus can be started from seed in your greenhouse or planted as purchased “crowns,” which are dormant one- or two-year-old plants.
It’ll take a few years for a full harvest after planting — two years for crown starts and three for seeds — but once your patch is established, you can enjoy the perennial plant for more than a decade.
With that level of commitment, it’s important to choose a bed site wisely. Some gardeners recommend raised beds to manage drainage problems and weed pressure.
If you’re planting into the ground, look for a level site that is well-drained, has loose fertile soil, receives good air flow and gets good sunlight.
Get a soil test before you plant and follow its recommendations to reach a pH level of 6.5 to 7.0. Any amendments should be tilled in 10-12 inches deep; when established, the plants have extensive root systems.
Adding phosphorus and lime at this stage is important, as you won’t be tilling into the ground again once the asparagus is planted.
You can also grow summer and fall cover crops on the bed this year to establish some organic matter there next spring.
Asparagus does not compete well with weeds, so weeding the bed a year ahead of planting gives the plants an advantage when they go into the ground.
Keeping a tilled border around the bed also helps manage weed intrusion. Each year, mulch around the plants with material like straw to keep additional weed growth down.
Plan to space the plants one foot apart from each other in rows five feet apart. The University of Maine Cooperative Extension recommends planting five crowns per each person you want to feed. A planting chart can also help.
Asparagus is susceptible to rust and airborne diseases, and setting up the bed in a north-south direction parallel with common wind direction will help keep the stalks dry and minimize leaf disease.
When you’re ready to plant next year, after frost danger has passed, dig furrows from six to eight inches wide so the roots will have room to spread. The furrows should be from six to eight inches deep in sandy soil and four in heavier soil.
Lay out the crowns with their roots spread and cover them with two inches of soil, then continue to fill the furrows in as the ferns grow. In the first three years, make sure the plants have an inch of water a week. Fertilize them in early April.
Harvest for two weeks the first season, three weeks the next and four from then on. Snap the stalks with your hands an inch or two below the soil surface but make sure the base of the plant is intact.
In Maine, it’s recommended to stop harvesting by June 15 (after that, let the tops keep growing).
To prepare the beds for the next year, weed them and add about 50 pounds of compost per square foot. In fall, cut back the dead stalks.
