By Sandi Simons-Crawford
Asparagus (Asparagus officinalis) is one of very few perennial vegetables. A properly managed bed will produce for 15 years or more. The taste of fresh asparagus from your garden rewards your initial effort and patience.
The Jersey series (Jersey Knight, Jersey Giant, Jersey Gem and others) are all-male hybrids that produce twice as many spears as older heirloom strains. They are resistant to major asparagus diseases and can be harvested the year after planting. Mary Washington is the standard heirloom variety. Purple Passion has thick deep burgundy spears that turn green when cooked; used raw in salads they provide extra color and crunch.
Plant 10 crowns (5 if planting the Jersey hybrids) for each family member to have enough asparagus for fresh table use.
The soil must be light and well drained for asparagus spears to grow straight. Don’t walk on the bed after the initial digging, as it compacts the soil. Full sun is best.
Prepare the bed a couple of months before spring planting. Cultivate the soil about 16 inches deep, breaking up clumps and working in organic amendments to assure good drainage. Don’t use peat moss; it will increase the soil’s acidity. Work compost into the top 3 or 4 inches.
Then take soil samples 12 inches deep, and deliver the samples to the Extension Center for testing. The test report will tell you if you need to add anything else. The ideal pH range is 6.0 to 6.7.
Crowns should be planted 12 inches apart, with rows at least 3 feet apart. Allow space for a path between rows so you can tend the bed without damaging the plants. Plant in late April or early May. Dig a trench 8 inches deep and wide enough to allow the roots to spread out. Place the crowns in the trench with the buds pointing upward, and cover with 2 inches of soil. Add a high phosphate starter fertilizer. Add soil around the plants 2 or 3 times during the next few weeks as the plants grow, until the trench is filled and you have a slight mound to prevent puddles.
Feeding & annual care
Asparagus is a heavy feeder. Follow the soil test recommendations. On average soils that have not been tested, broadcast a complete fertilizer (like 5-10-10) in mid-March at the rate of 2 to 5 pounds per 100 square feet, then add a second application at the end of the cutting season. Organic growers should add regular applications of compost or well-rotted manure during spring and summer.
Keep free of weeds and water deeply. Heavy hay, straw or leaf mulch may be applied in mid-summer. The ferns that grow feed the roots; don’t cut them back until they die naturally in the fall.
Do not harvest asparagus the first growing season. Harvest the second year for a short period (two weeks maximum). This allows the plants to become established. After the second year harvest for 6 to 8 weeks each year. Cut or snap the spears at ground level, but be careful not to damage spears that have not yet emerged. Asparagus develops fiber rapidly after harvest, so wash and cool immediately.
Sandi Simons-Crawford is a Master Gardener Volunteer in Haywood County. For more information call the Haywood County Extension Center at 828.456.3575.