Growers who wish to plant a few acres of asparagus for spear production probably should buy crowns from an experienced crown grower or nursery rather than grow crowns for themselves. However, if growers decide to plant 20 or more acres of asparagus for spear production, it might be more economical for them to grow their own crowns. Crown production is a specialized annual row crop. To grow good crowns, vigorous seed should be planted in soil that has never grown asparagus. Soil should be light textured so crowns can be easily dug and freed from adhering soil. Phosphorus and potassium fertilizer, and limestone, if needed, should be applied based on soil test information and worked into the soil before seeding the crown bed.
Approximately 30 lbs of actual nitrogen per acre should be applied at planting and an additional 50 lbs per acre topdressed in mid-summer.
Unless the seed tag states that the seed has been treated with bleach, apply an approved fungicide to the seeds at the recommended rate. Seed should be planted around the frost-free date in rows three feet apart. Eight seeds are planted per foot of row. One pound of good-quality male hybrid seed contains about 15,000 seeds and allowing for some failure of germination, should produce crowns for planting two acres of asparagus at a permanent spacing of 5 feet between rows and 1 1/2 feet between plants in the row. One pound of seed spaced at the above recommendation should take up one-tenth of an acre. A seed-planting depth of 1 to 1 1/2 inches is optimum. Asparagus seed is slow to germinate, requiring 2 to 3 weeks for the seedlings to emerge. Subsequently developed crowns can be dug one year later anytime in the following spring before growth of the buds has begun and just before setting in the field.
Old plant tops should be mowed and, if necessary, removed from the field so as not to interfere with digging the crowns. A peanut or potato digger can be used to lift the asparagus crowns from the nursery row. Care should be taken not to injure the crowns during digging. Crowns should be planted as soon as possible after digging.
If it is necessary to hold the dug crowns before planting them in the field, store them in a moderately dry cold storage facility at a temperature between 30 and 32 degrees F. Do not store in a refrigerator that contains apples. Ethylene given off by the ripening apples will cause the asparagus buds to remain dormant. Crowns can become overheated if they are stored in a large pile or left on a truck with poor ventilation. Extreme drying of the crowns should be avoided. Storing crowns at temperatures below 28 degrees F could result in severe injury or even death.
Shoot growth and mold can quickly develop if stored between 35 and 40 degrees F.