Asparagus needs a cold winters where the ground freezes and a somewhat dry summer. It needs well drained almost sandy soil to prosper. Full sun is also an important requirement. A crown is a one year old root system of asparagus grown from seed. It looks like a stringy mop or alien creature. Purchasing disease free crowns is the recommended way to start your asparagus patch. You will not be harvesting the first year in order to let it establish a strong, deep root system. If you start from seed it will take and additional 2 years before you can harvest.
Choosing Asparagus Varieties
Asparagus plants are monoecious plants meaning they are either male or female plants. Male plants produce more shoots while female plants must invest energy in producing seed and produce fewer shoots. Jersey Knight or Jersey Giant produce all male shoots. While we commonly think of asparagus as green there is a purple variety called Purple Passion.
Plan on each crown you plant producing 1/2 lb of shoots when mature. I planted a 4x8 bed which is adequate for my husband and me.
Planting in a raised beds makes weeding and maintenance easier. A raised bed also warms up earlier in the spring and allows you to properly amend your soil with plenty of organic matter. Be sure to start with a sandy loam soil and add compost. Raised beds will drain better preventing the crowns from rotting.
Dig a trench down two sides of your raised bed. The trench should be about 1 foot deep. You can add a dry organic fertilizer to the trench. Place the crowns in the trench about a foot to a 1 1/2 ft apart. Cover with 3 inches of soil. Continue adding soil as the plants emerge until it is level with the soil line.
Each spring add some dry organic fertilizer of bone meal and blood meal to the bed and mulch with compost around the plants. Keep the bed free of weeds. The first two years water regularly. As asparagus matures it sends down deep roots and can go longer without water.
After the fronds die back leave them there through the winter to act as a protective mulch. In the spring before the spears emerge cut the foliage to the ground and remove it.
Remember not to harvest the first year. After that cut or snap off 5-7 inches shoots with tight tips. As the tips open or loosen up the shoot become fibrous and not suitable for eating. The diameter of the spear does not affect tenderness. When harvesting cut all spears not allowing any to fern out. This will stimulate budding. Also you do not have to cut spears below the surface of the soil that may damage other developing shoots. Below is the time frame for harvesting each year.
Harvest for 3 weeks
Harvest for 4-6 weeks
Fourth Year and Consecutive Years
Harvest 6-8 weeks
The length of your harvest season will depend on the air temperature. As the air temperature increases the frequency of harvesting will increase. Quit harvesting when 3/4's of the spears diameters are less than 3/8's of an inch.
It is best to harvest in the morning. Submerge the spears in cold water to cool then store in a plastic bag in the refrigerator for 1-2 weeks. Enjoy!