Asparagus is a perennial will grow larger and more productive each year and produce for many years with almost no maintenance, if you plant it properly. You can harvest handfuls of crisp, sweet stalks all during spring from an established patch. All you have to do is invest some time and effort to get your plants started, and patiently wait a few years for them to get established before you start to harvest.
A common mistake with asparagus is to underestimate how many plants you actually need. Remember that while each plant may produce a pound or more of fresh spear each season, there are only one or two spears per plant on any given day. If you want to cut a family-sized harvest into your cooking pot, you’ll need six to ten productive plants per family member in your asparagus patch.
You can plant asparagus any time the soil temperature exceeds 50 degrees. Start with two-year-old container-grown plants if your budget permits; if not you can get one-year roots. Planting holes should be one foot deep and wide, spaced two feet apart. If you are planting in trenches, rows should be spaced five feet apart. Giving the plants lots of room helps prevent fungus diseases by letting air circulate to keep them dry. Good drainage is important; waterlogged soils will lead to root rot.
Sprinkle some 0-21-0 (triple super-phosphate) fertilizer in the bottom of the planting holes or trench before planting. Fill half full with compost or aged manure, sprinkle on some 10-10-10 fertilizer or Espoma Plant-Tone, and plant the roots so that the base of the plant (root crown) is about four inches below ground level. Only fill to the tips of the plants; if your plants don’t have stalks yet, wait for them to grow before backfilling around them.
The best weed control is mulching. You can use straw, composted leaves, or grass clippings for this purpose. If you have a problem with perennial weeds, after harvest is over you can cut all the plants to the ground and then spray the row with Roundup to kill the weeds, and then let the asparagus re-grow.
You’ll need to wait a year before you harvest. Let the plants grow all season, fertilizing occasionally and mulching to prevent weeds. After frost kills the tops cut them off. Repeat this the second year. Start harvesting next year, but only cut while spears are at least as thick as your finger. After harvest is over let the remaining stalks grow tall.
Asparagus beetles chew on the fern, causing the stem to turn brown and reducing the yield the next year. If Asparagus beetles are seen, spray the ferns with an approved insecticide. For disease prevention, spray with an approved fungicide on a 7 to 14 day schedule beginning when the ferns reach a 3 to 4 foot height and continuing until mid September.
Here are our recommended varieties for the Ohio valley:
Jersey Knight produces a bumper crop of large, fat spears, typically 5/8-inch in diameter, bright green with deep purple tips. One of the easiest varieties to grow, they have terrific vigor that makes these plants come back stronger every year. The yield from Jersey Knight is 2 to 4 times greater than older strains such as the Washington series, highly rust-resistant and tolerant of Fusarium, Crown and Rust Rot.
Purple Passion spears are larger and more tender than green asparagus, without any of the strings that can make green asparagus tough. The whole spear can be cooked without wasting the butt. It has so much more natural sugar it’s often snapped off and eaten raw (its color makes it a distinctive salad garnish) but when it’s cooked its sweetness gives it a mild, nutty flavor.
Steve Boehme is the owner of GoodSeed Farm Country Nursery & Landscape, located on Old State Route 32 three miles west of Peebles. To e-mail your landscaping questions or subscribe to this column online click “Contact Us” from their website at www.goodseedfarm.com or call (937) 587-7021.