Indiana Berry

Asparagus is a long-lived perennial vegetable crop that is enjoyed by many gardeners. It can be productive for 15 or more years if given proper care. A gourmet treat sometimes can be expensive to purchase and never fresh, asparagus can be grown in almost any garden where there’s a cold and dry season to provide dormant period. 
  When choosing a location you should allow for enough space to prevent crowding and to be a permanent location. The location should receive full sun, with some windbreak. Ideal soil is well-drained, rich, sandy loam. Poorly drained or clay soils should be amended or create a raised bed. Keep in mind that asparagus is a perennial plant, so plant for a permanent location.  Asparagus itself requires full sun and a place where is not subjected to strong winds. 
  Asparagus should be planted as soon as possible in the spring. Dig a trench 12-18 inches wide. Make the trench a minimum of 6" deep, depending on whether you are going to add compost material. If adding compost, make the trench 1-10 inches deep. Add enough compost material so that after it is firmed down the trench is 6" deep. Add 1/2 pound of 10-10-10 fertilizer to each 10 foot stretch of trench. Place the crowns 9-12 inches apart with the roots spread out uniformly and the crown in an upright, centered position. Cover with 2" of soil. As the tips begin growing, gradually add more soil to the trench until the trench is full. This process takes approximately 6 weeks. 
  Do not harvest any asparagus the first year of planting, the following year you may harvest asparagus several times throughout a three-week period. Two years after planting, the length of harvest can increase to about 4 to 6 weeks. The third year after planting and thereafter, harvesting can continue for 6 to 8 weeks. Since the length of harvest season will vary from year to year depending on air temperature, stop the harvest when the diameter of 3-4 of the spears becomes small (less than 3-8 inch). 
Asparagus spears typically start to emerge when the soil temperature reaches 50 degrees F. Growth of asparagus is dependent on air temperature. Early in the season, 7-9 inch spears might be harvested every 2 to 4 days. Air temperatures increase, harvesting frequencies will increase to once or twice per days. Harvest asparagus by snapping 7 to 9-inch spears with tight tips. There is no need to cut asparagus below the soil with a knife. This may injure other buds on the crown that will send up new spears. The small stub that is left in the soil after snapping dries up and disintegrates. A new spear does not come up the same spot, but from another bud on the crown. As the tips of the spears, causing them to become tough. The diameter of the spear has no bearing on its toughness. 
  Once you harvest is complete, snap all the remaining spears off at ground level. To encourage foliage growth for the rest of the growing season, apply a 10-10-10 or similar fertilizer per 50 feet of row. Now is the time to remove existing weeds, either by shallow cultivation, hand pulling or with herbicide according to level directions. New spears will then emerge; fern out, and provide a large canopy to cover the space between the rows. After plants have gone dormant, late winter, early spring mow off the tops close to the ground, before new growth appears. 
It is important to keep them free of weeds, be especially careful to prevent perennial weeds, such as dock and dandelion from getting established. Any weeds that appear should be removed as soon as possible. Never cut or remove the foliage until the asparagus has become completely dormant, these ferns produce the energy that roots store. Only female plants produce berries (seeds). If you don't need to save them for new plants, remove them as soon as they appear. 
Do not use salt as a weed killer. It will not harm the asparagus, but it inhibits water penetration in the soil. Also, rains can leach the salt out of the asparagus bed and into the rest of the garden, injuring other vegetables that are less salt tolerant than asparagus. 
 

Sam's Tip:
Asparagus will tell you when to start and stop picking.  When the spears look like the ones you find in the store, go ahead and pick them.  The crown will continue breaking the largest bud and producing smaller and smaller spears throughout the growing season until the spears are too small to pick.  At that time stop picking so the crown can begin rebuilding for next spring.

DO NOT use salt as a weed killer.  It does not harm the asparagus but it will inhibit water penetration in the soil.  It can also leach out when it rains and damage other plants.