Asparagus is one of the highlights of the spring vegetable garden. These perennial vegetables are a snap to grow once they are established, and you can enjoy your own perfectly tender, sweet asparagus year after year. They do require a bit of space and take a few years to get going, but it is well worth the time and effort to be able to have several weeks' worth of asparagus ready to harvest each spring.
Where to Grow Asparagus
Asparagus is hardy to zone three, growing well in zones three through eight. They grow best in full sun, in fertile, well-drained soil.
After the shoots form in spring, the plants send up airy mounds of ferny, feathery foliage that can reach two to five feet tall and about two to four feet wide. Small white blossoms form in summer.
How to Plant Asparagus
Asparagus is most commonly planted from crowns. This can be done in fall, or in spring as long as the soil temperature is above fifty degrees. Asparagus crowns are readily available in most garden centers, as well as through catalogs and online. Plant asparagus crowns fifteen to eighteen inches apart, depending on the variety. Dig a trench about a foot deep, and fill with about four inches of compost or well-rotted manure. When new shoots appear, cover them with an additional two to four inches of an even mix of compost and soil. As the shoots keep growing, continue filling the trench with more compost and soil, then mulch the area well with grass clippings, straw, pine straw, or shredded bark mulch.
Tips for Growing Organic Asparagus
Asparagus takes a few years to really start producing. The first year, don't do any harvesting. The second year, you can harvest about a third of the spears. But by the third year, you can harvest all you want. It's important to keep asparagus moist, but not soggy.
When planted in a good soil and compost or manure mix, asparagus doesn't need a much in the way of additional fertilizers. Every year, topdress the asparagus bed with more compost or composted manure. The ferny foliage that emerges should be left standing all season long, but can be trimmed back when it is killed back by frost. The purpose of this foliage is to help the plants store energy for the next season's spear production.
Asparagus has a few pest and disease problems, the most common of which is the asparagus beetle. The best way to control asparagus beetles is to hand-pick them. Asparagus can also develop crown or root rot, as well as fusarium wilt. The only way to effectively deal with these issues is to remove any infected plants and dispose of them in the trash.
As noted above, for the first couple of years, you'll have to leave most of the asparagus you grow to help grow stronger roots and build up energy for the next year's harvest. When you do harvest, do so when the spears are six to ten inches above the soil line. The buds should still be tightly closed and firm. Just snap or cut the spear off at the soil line. You can harvest asparagus for about six to eight weeks each spring, generally starting in late March to early April for most gardeners. If you are noticing decreased production in your asparagus plants, stop harvesting and let the plant store energy for next season, being sure to also give it a good side-dressing of compost or composted manure.
Recommended Asparagus Varieties
- 'Jersey Giant'
- 'Jersey Knight'
- 'Purple Passion'
- 'Mary Washington'