Tips and techniques for how to grow asparagus; one of the few perennial vegetable crops!
Sunlight: Full sun to partial shade
Maturity: 1-3 years from crowns
Height: 5 to 8 feet
Spacing: 12 to 24 inches apart, 2 to 3 feet between rows
Home gardeners are growing asparagus everywhere in the United States except where conditions are too mild — Florida and the Gulf Coast — to satisfy its dormancy requirements. The perennial plant does well in backyard beds and thrives in raised bed gardens.
Tender shoots are picked as young spears early in the spring. Later in the season the foliage matures into a delicate fern which changes to a golden color in the fall. Plants can be productive for 15 years or more and delicious spears are packed with vitamin C, B-vitamins, iron, potassium and calcium.
Provide as much sun as possible and a sandy, fast draining soil for the plants. Poor drainage will cause the roots to rot. Keep roots 12-18 inches away from fences and sidewalks. Beds of asparagus will fill in over the years. Many gardeners with space imitations use asparagus as a border or hedge plant. If possible, plant on the north side of your garden to prevent shading other vegetable crops.
Tip: Practice organic weed control to boost yields. Asparagus does not compete well with weeds — mulch the bed well with organic compost, leaves or straw and pull any weeds that may appear.
How to Plant:
Dig a trench 1 foot wide and 8-10 inches deep. Mix in rock phosphate to improve plant production and vigor. The bare root plants — or crowns — should be spaced 1 foot apart, setting them in the soil so that the tops of the crowns are 6-8 inches below the top of the trench. Spread the crowns out on the bottom of the trench and cover with 2 inches of soil or garden compost. As the plants begin to grow, fill in the trench gradually with soil but never cover the emerging tips (green part). In other words:
- Dig a hole
- Add organic fertilizer
- Spread out the crowns and barely cover with soil
- As they grow, gradually fill in the trench
Note: Studies have shown that the deeper asparagus crowns are buried, the more productive they will be.
You won’t harvest many spears the first year or two. It’s important to allow the bed to become well established before harvesting. In fall or winter, when the plants turn brown, cut all the foliage back to the ground and cover with a thick layer of mulch. When the plants are ready to harvest, select spears that are 6-8 inches tall and at least 1/2 inch thick with tightly closed tips. Cut close to the soil line.
Insects and Diseases:
If the foliage turns yellow and plants becomes stunted, look for ants. They are a sure sign that your asparagus is being attacked by aphids. Defoliated plants and misshapen young spears indicate asparagus beetle damage.
Asparagus rust may be observed shortly after the cutting season. The spores of rust disease create reddish brown masses on ferns. When these areas are touched they give off a dusty cloud.
Seed Saving Instructions:
Female asparagus flowers produce round reddish, 3/8 inch berries containing six seeds. Birds find the berries tasty and often damage crops that are not covered. Harvest the ripe berries before they drop from the plants. The fruits can be rubbed over a screen to free the seeds which are then washed in water. Dry the seeds away from direct sunlight for several days before storing.