Illinois has experienced a mild winter for 2024. Dandelions popped up in my yard on Feb. 8. March saw an early bloom for several trees, such as maples. However, even with these early flowers, there is one thing that really makes spring feel like spring — asparagus.
Asparagus is one of the few garden crops we grow that is a perennial. Plant it once, and it will come back each spring. Sounds too good to be true? The plant is easy to grow and can be found springing up in backyards around Illinois. So, how can you get asparagus off to a good start and keep it going season after season?
Selecting which type to grow
Asparagus plants are dioicous, meaning they are either male or female. While female plants tend to produce larger spears, they produce fewer of them. In addition, female plants will produce fruit and seeds, which take considerable energy from the plant, and sprout new seedlings, which may cause overcrowding, making them weedy. As a result, most gardeners prefer the easy management of male asparagus.
While you can buy inexpensive asparagus seeds, many gardeners opt for asparagus crowns. Crowns are 1-year-old plants that come from a known cultivar and will almost always be male. If you decide to grow asparagus from seed, you’ll need to wait three or four years before you can start harvesting. With crowns, you can begin harvesting small amounts the year after they are planted.
Planting
Asparagus roots grow deep and spread out 5 feet or more. So, be sure your asparagus patch has plenty of room and is in full sun. Asparagus can be planted as soon as the ground can be worked in the spring (typically March 15-April 15).
- Dig a trench that is 12-18 inches wide and 6 inches deep.
- Place the crowns 9-12 inches apart in the trench, making sure the bud side is up.
- Once the crowns are in the trench, you don’t want to fill the trench with soil. Instead, cover them with 2 inches of soil and continue to fill the trench as the plants grow taller during the growing season.
Maintenance
The most common issue I encounter with asparagus is controlling weeds. In the early spring before asparagus shoots emerge, shallowly cultivate your soil to eliminate weeds. Then, add a layer of mulch to help suppress weeds. As the growing season goes on, continue to remove weeds. Arborist wood chips, straw or shredded fall leaves work well as a mulch that will break down and add nutrients back to the soil.
Even though it can be a bit unsightly, it’s best to leave the fern-like growth until it begins to die back in the fall. Like spring bulbs, the foliage of asparagus helps generate energy for the following year.
Harvest
Biting into a spear of freshly picked asparagus gives a satisfying crunch that can be enjoyed right in the garden, but questions often surround asparagus harvest. Picking too much too early will lead to weak plants and lower yields down the road. Here are some tips:
- The year you plant your asparagus crowns, avoid harvesting any. Let the spears grow and develop “ferns” (leaves).
- The year after planting, harvest for up to two weeks.
- In the third year, harvest for up to four weeks.
- Finally, in year four and onwards, harvest through May or June, as long as the spears are larger than 3/8 inch in diameter (the thickness of a pencil).
- Harvest spears when they are 5-8 inches tall by either cutting or snapping.
Asparagus is a versatile and nutritious vegetable that can be enjoyed in many ways. Once harvested, they can be roasted, grilled, steamed, sauteed, pickled or left raw. The options are endless.
