Invest in Asparagus
Asparagus is a vegetable that’s good looking enough to be planted in the flower garden. The foliage makes an excellent garden backdrop or can be used in sunny beds to give light shade to flowers that prefer partial shade. I remember a flower garden where asparagus provided shade for an under-story planting of impatients and verbena. The effect was most attractive as the asparagus foliage created the impression of looking through a light fog.
The lacy foliage varies from light-green to purplish-green depending on variety. Several harvests of the spears can be made before you allow the stems to grow to maturity.
To keep volunteers from taking over your flower garden, seek to buy male plants. If that’s not doable, dig out the berry-producing female plants.
Asparagus requires advance preparations and well-drained soil.
Asparagus are grown from roots purchased from nurseries, garden catalogs or garden centers. The roots are generally packaged in bundles of 10 to 25. Most asparagus roots are dug up in the fall and placed in cold storage for spring planting. However, soil preparation should start in the fall with a soil test. Asparagus is a long-term crop, so the pH and nutrient concentrations should be at their optimum levels from the very beginning.
In commercial production, roots are planted deep to facilitate harvesting and minimize irrigation. Mechanical harvesters cut spears below the surface of the soil.
Home gardeners who plant their asparagus roots deep can cut the spears underground, harvesting white-stemmed spears. Asparagus crowns can alternately be planted just a few inches below the surface of the soil. But shallow-planted beds are likely to need irrigating.
To prepare an asparagus bed for cutting spears below the surface of the ground, remove the top six inches of soil in a trench approximately 12 inches wide. In the bottom of the trench, add a two-inch-thick layer of compost and spade or rototill as deeply as possible. Cover the excavated soil with an inch of compost and blend it with the soil. In the spring, remove about a two-inch layer of soil from the ditch and spread the roots of each asparagus crown, spacing crowns a foot apart. Cover the crowns with two to three inches of the amended soil. Check the trench weekly and add additional soil as the stems elongate. Avoid covering the spears.
If you are planting the crowns shallow, incorporate a one- to two-inch layer of compost as deep as possible into the soil and dig a three- to four-inch-deep trench for planting the crowns.
Do not harvest asparagus spears until the beginning of the third growing season. The first harvest should be limited to two or three cuttings. At the end of the harvesting season, mulch the bed with a two-inch layer of compost. For additional growth, spread one-half cup of calcium nitrate per 10 square feet.
The onion hoe is the ideal tool for weeding asparagus beds.
I apply Preen only after the harvest is complete with a second application in September to control winter weeds. Preen, which is made from fluoride, is cleared for use on vegetables and will control grasses but only a few broadleaf weeds. It is most effective when applied on clean, cultivated soil and watered or cultivated into the soil immediately. Preen provides weed control for only six to eight weeks.
Ask Dr. Gouin your questions at [email protected]. Please include your name and address.