After the asparagus has been planted (see our previous post on asparagus), growing it takes patience and it goes like this. Year one. Plant the crowns. Years two and three. Resist temptation.
During this time, especially if the shoots are small, it’s important to resist the urge to pick them. They are actually part of the plant itself, not the fruit, so harvesting too early actually weakens the plant. The shoots grow into ferns which provide energy that goes into developing a healthy crown and a strong root system. A healthy, mature crown will then put out a multiple of spears.
Keeping the asparagus bed free of weeds helps to prevent fungal disease. The easiest way to accomplish this is to provide a layer of mulch. Mulch performs several functions; those of keeping the soil moist, and limiting weed growth. In winter in cold climates it also protects the crowns which stimulates the shoots into earlier production. We first tried using straw for mulching, but found it a breeding ground for slugs. We now use leaves, raked every fall into piles that are then placed onto all of our pathways. With forest all around our garden, leaves are abundant.
There is a possibility of Asparagus beetles invading the patch, although we haven’t seen them here. There are two types of beetles that invade asparagus patches so if you think you have them, Google “asparagus beetle” to find a strategy for dealing with the type you have. The beetles feed on shoots in spring and the ferns in summer.
Asparagus spears can grow as much as ten inches in a single day. They are ready to pick when the stalks reach around 8 inches tall and the spears are still tightly closed. The harvest season should last approximately six to seven weeks in spring through early summer. The number and diameter of the spears will dwindle toward the end of the season, showing that the crown is getting distressed and the harvest time is over.
When the spears begin to dwindle, stop harvesting. The remaining spears will grow into ferns. Let the ferns keep growing through summer and into autumn. They will reach heights of up to five feet.
In the fall, when the ferns turn yellow, cut them to the ground. Asparagus rust is a wind-borne fungus that may overwinter on plants that are not cut down. Cutting the ferns in the fall also keeps asparagus beetles from overwintering on uncut plants. -G.H.