Asparagus occupies the same area for many years, making composting and/or fertilizing important to assure an optimum crop. Apply general fertilizer in early spring before any visible growth begins, and again in the autumn.
Prepare a planting area
We decided we wanted our asparagus in a raised bed. Wherever you plant your asparagus patch should be an area that you can allocate for asparagus alone, since it is a perennial.
Weed the area before planting. Being organic gardeners, we don't spray with herbicides or weed killers; the way you prepare your beds is up to you. For small areas good old-fashioned hand weeding or tilling does a good job.
Like many plants, asparagus is available in different varieties and colors. Some species of asparagus, like Asparagus africanus (African asparagus), can grow 20 to 30 feet tall. Wild asparagus, species A. officinalis, A. schoberioides or A. microraphis grow naturally in zones 4a-9b. You may have seen or tried Prussian asparagus (Bath Asparagus or Pyrenees Star of Bethlehem), which is not related to asparagus, as its name suggests.
Prussian asparagus (Ornithogalum pyrenaicum) is sometimes marketed along side asparagus, with its long, slender spears that can be served like asparagus. Asparagus officinalis is the genus and species of asparagus grown in sunny vegetable gardens.
A favorite of mine is purple asparagus, with its sweet flavor and rich, chocolate garden color tones. Purple asparagus (Violetto d'Albenga) originated from the Albenga, Italy region. In the past, purple asparagus has not been as prolific as its green counterparts and has been more suseptible to asparagus rust. More recent hybrids are better yielding and more disease resistant.
Rutgers, the State University of NJ is a producer of many of the well known asparagus hybrids. Recently introduced NJ1064 - an all-male, disease resistant, purple hybrid - out yields Purple Passion, a popular commercial hybrid, by approximately 25%.
Rutgers' program strives to release asparagus with desirable attributes of overall good quality, rust and disease resistance, and high yielding (preferably all-male) plants. Asparagus is dioecious (male and female plants). Female plants tend to produce larger spears later in the growing season and allocate more energy into bearing berries in the fall, rather than producing high yields.
Based on U.S. market sales of white asparagus, growing asparagus in deprived light (etiolation) seems to have limited appeal to most Americans. But in the Netherlands, France, Belgium and Germany, white asparagus, known as 'white gold', is quite popular. White asparagus cultivars include: Gijnlim, Grolim, Ravel, Darbella and Dariana.
Growing the plants with restricted light, denies the asparagus chlorophyll production plus tones down its characteristically strong flavor.
Seeds or Crowns?
Asparagus seeds and crowns are readily available from many garden suppliers. Asparagus can be grown from seed, but is more often started from one- or two-year-old crowns (roots). Planting crowns gives the grower a head start on crop production. We started our asparagus patch with two-year-old crowns. The first year we let the plants go to fern to establish a strong root system. Then our harvesting began the following year.
Upon receiving your asparagus crowns, store them in a dark, cool, dry place until you are ready to plant, as you would any roots or tubers. We stored ours in box or bag with peat moss. When you are ready to plant, carefully separate the roots. Dipping the asparagus crowns in a fungicide solution before planting is optional. Some gardeners and growing experts recommend fungicide dipping; some do not. We opted not to dip the crowns and did not have any problems.
When I was writing about Goji plants in the fall of 2008, I spoke with Goji and Asparagus grower Scott D. Walker of Jersey Asparagus Farms, located in Pittsgrove, NJ, about when to cut back the asparagus ferns. Scott advised to cut the ferns back in the fall, "As for asparagus, you will want to wait until the fern is brown and dormant. If it has yellow in it, then there is still some food in the fern that is making its way down into the root. This will be stored and used next spring when the spears start to emerge. If you cut the fern green you go into the winter with a gas tank that is not completely full. Then you won't be getting the mileage (high yields) that you could next spring when you start to harvest."
He added that, depending on where we live, the ferns will turn brown later in some areas than in others. "It takes a few, pretty hard frosts to turn the fern brown. You can remove it in the late fall or early spring. The key is to remove it before the spears start to emerge next spring." Once asparagus pops up in early spring, it is important to harvest the spears daily, since growth is rapid and your asparagus can go to ferns in the blink of an eye.
Asparagus is a good source of folate, vitamin A and iron, and is an excellent source of vitamin K. The healthy spears contain an abundance of other nutrients including: magnesium, phosphorus, potassium, zinc, and significant amounts of vitamin C, riboflavin and dietary fiber.
Asparagus also contains high quality proteins, including glutathione and all the essential amino acids, in addition to high levels of rutin and protodioscin, a cancer fighting, steroidal saponin. Glutathione and Rutin are potent antioxidants and a scavengers of free radicals.
Asparagus Nutrition Analysis: 80g uncooked (approximately 4 large spears): protein: 1.76g (4%DV), dietary Fiber: 1.6g (6%DV), Iron: 1.72mg (10%DV), Magnesium: 12mg (3%DV), Phosphorus: 40mg (4%DV), Potassium 160mg (5%DV), Zinc: .44mg (3%DV), Vitamin C: 4.4mg (7%DV), Riboflavin: .112mg (7%DV), Niacin: .784mg (4%DV), Folate: 40mcg (10%DV), Vitamin A: 604IU (12%DV), Vitamin E: 1.37IU (5%DV), Vitamin K: 33.2mcg (42%DV)
- For maximum water-soluble nutrient retention (mainly B vitamins and vitamin C) try dry heat cooking methods, such as grilling or oven roasting.
- Our favorite healthy asparagus recipe is to simply lay the asparagus in a single layer on a baking sheet, drizzle it with a little olive oil, turn the asparagus (using tongs) to apply a light coating of oil and then roast in a 350°F (177°C) oven until the desired doneness. We like to finish it off by topping the asparagus with a handful of diced tomatoes along with a sprinkle of Parmesan cheese and freshly ground black pepper. Then just before serving, return the pan to the oven just long enough to warm the tomatoes and lightly brown the cheese.
- To keep your asparagus garden fresh, stand the fresh cut or store bought spears in one-inch of water, in a container in the refrigerator. It works great!
Asparagus Nutrition Analysis by Diana Wind using government data provided by the USDA Nutrient database for standard reference. Percent Daily Value (%DV)...
Photo credits: Three kinds of Asparagus at a Boston, Massachusetts, USA market - Photo courtesy of GearedBull, Jim Hood and Rebecca Foster - Published on Wikimedia Commons - GNU Free Documentation License. Purple Passion Asparagus Copyright ©Jenhillphoto. All rights reserved. Used with permission; Thanks to Dave's Garden member Jenhillphoto! All other photographs Copyright 2010 Wind. All rights reserved.
More Asparagus "Tips" by California Asparagus Commission
Growing Asparagus - South Dakota State University by David F. Graper and Rhoda Burrows