When to plant
Asparagus crowns can be planted earlier than most other vegetables. The ideal time is late winter, after danger of a hard freeze has passed but before other plants have really begun to grow.
For Southern growers in zone 8 or higher, crowns can be planted as early as mid-February. Check with local extension agents for planting dates in your region.
Site selection and preparation
Since asparagus is a perennial, be sure to consider how you will manage the bed in the years to come before planting.
Choose a sunny spot with well-draining loose soil. Heavy clay soils can be conditioned in advance with the addition of leaf mold or straw and then finely tilled.
Asparagus doesn’t like very acidic soils, so get a soil test if you’re unsure about your site. Work in nutrient rich compost and/or granulated fertilizer to feed the crowns in the spring.
Planting and Care
Asparagus crowns are usually planted in 12 inches apart in rows spaced 5 feet apart. Dig a trench 8 inches deep that is about 4 to 6 inches wide. Lay crowns in trench with the roots fanned out with the buds pointing up.
Cover the crowns with a few inches of soil. As the plants begin to grown and push through the soil, cover them with another inch or two. Continue covering the crowns as they grow until the trench is filled.
Weed the bed as needed and each year in early spring before harvest begins, give the plants some fertilizer.
Do not harvest the asparagus in the year it was planted. The following season (year 2), harvest the new shoots that appear for only 2 weeks.
The following season (year 3) harvest the spears for 4 weeks, and then in year 4 harvest for the full 6-8 weeks that new shoots appear.
The annual harvest is over when most of the new shoots are skinnier than a pencil. At that point, allow the plants to “fern out” for the season.
In late fall, after the first frost when the plants have turned brown, cut down the ferns and add them to the compost pile. A good layer of mulch and compost can be added to enrich the soil for spring.