Jane McLeod: Growing asparagus is a snap
February 8, 2010
Planting asparagus is probably one of the best investments a vegetable gardener can make.
Because asparagus takes a couple of years before it can be harvested, it starts out as a crop for the patient gardener, but after that, it is ideal for the impatient gardener as it pops out of the ground almost overnight, sweet, tender and ready for dinner.
Asparagus, a hardy member of the lily family, is one of the few perennial vegetables. It needs a sunny spot; lots of room, with about 12 plants per asparagus lover; a dormant period; and well-drained, very amended soil dug deep, to at least 18 inches, to foster strong roots needed to ensure harvest.
Asparagus roots often are referred to as crowns. Plant them in a trench or individual holes. Asparagus roots are long, white, hang like the tentacles of an octopus, and should be fresh and firm. Untangle the roots as best you can and spread them over a mound of compost with the center of the crown facing upward. Ideally, they should be spaced a good 18 inches from center to center, but if your soil is rich, reduce the distance to 12 inches.
Locally, plant asparagus in early spring, when the ground is workable and the crowns are dormant. As long as the crowns are covered with about 3 inches of soil, they won't suffer in a freeze. The depth for planting the crowns depends on the asparagus variety and planting method.
The deeper planting method is to dig down about 12 inches, add a couple of inches of compost for under the crown, then create the mound. At this point, the top of the mound is about 6 inches below the soil surface. The shallower method is to plant just 3 or 4 inches deep, then add a few inches of new soil to the top of the bed every other spring.
Asparagus roots tend to rise to the surface of the soil throughout time and what you are trying to do is keep the asparagus growing at the right depth — optimally, 6 to 8 inches. Planting too shallow yields many spindly spears, while planting too deep produces fewer and larger ones. Either way, once planted, fill the hole with about 3 inches of soil, water the plants well, and as the spears grow, keep filling soil to the surface.
In a few weeks, asparagus will start sending up tiny spindly spears, but do not cut any of them. They will quickly sprout into tall ferny foliage. For the first summer, just weed and water. By the second summer, the spears will be considerably fatter and tempting to cut, but do so very sparingly, if at all. Any spear you harvest will not develop into foliage and it is this foliage that feeds and strengthens the roots. Indulge yourself a little in Year 3 and by Year 5, you can harvest for six to eight weeks before letting the remaining spears turn into foliage.
In the fall, as the ferns turn yellow, they continue to feed the roots so cut them down as late as possible.
Nothing you grow will ever give you as good a return as asparagus and since a bed of asparagus will produce for decades, the time lag between planting and first harvest is rewarded by years of savory feasting.
Jane McLeod is a master gardener through the Routt County Cooperative Extension Office. Call 879-0825 with questions.