How to Grow Asparagus

Once the plants get established – after the first year or so – asparagus needs little water except in drought or arid conditions. It is a deep-rooted plant with roots systems reaching to 10 feet, is native to sandy soil and is well able to withstand dry conditions. It doesn’t require a lot of fertilization either, using only small amounts of nitrogen and phosphorus. Asparagus does have a relatively high potassium requirement, (the last of the three numbers on a fertilizer bag: nitrogen, phosphorus, and potash or potassium). Potassium provides overall plant health by aiding in a plant’s cold-hardiness and ability to fight off the effects of drought, disease and pests. To add potassium, organic gardeners can apply a side dressing of greensand, available in most nurseries. Banana peels are also an excellent source of potassium and provide organic matter to the soil – and the worms love them.

To cut or to snap

A spear of asparagus can grow 10 inches in a single day. You’ll have the urge to pick those tender green shoots almost as soon as they appear; don’t. Resist the temptation for one, two, even three years after planting, depending on the vigor of the plant. Remember you are harvesting part of the plant, not the fruit. Shoots eventually grow into the fern, which provides energy to develop a healthy crown and strong root system. Harvesting too soon will result in a weak plant.

The second or third year after planting the crowns, begin harvesting. Harvest usually lasts for about six to seven weeks in spring and early summer. Spears ready to pick are usually between 8 and 10 inches tall and with the tips still tightly closed. Contrary to popular belief, the larger diameter spears are of better quality and most tender. “Whips” – or the smaller diameter spears – are tougher because most of asparagus’ fiber is contained in the skin. When the number and diameter of the spears ready to pick decreases considerably, the crown is starting to show signs of stress and harvest season is done.

There are two methods of harvesting the spears: either cutting or snapping them from the crown. Most of the world cuts them, but according to the Michigan Asparagus Advisory Board, its state – which ranks third in the nation in asparagus production behind California and Washington – likes to boast Michigan’s asparagus is unique because it’s hand-snapped above the ground. It makes no difference to the plant. The advantage to either method is in cooking and storage. When snapping the spear, it will generally break off above the woody, inedible butt-end, so it will not need to be trimmed.