January 23, 1998
Asparagus is one of those vegetables that, if you have the room, you really should make an effort to grow. Being a perennial, the plant is fairly low maintenance that is, after the work needed to establish a bed. Also, it's one of the few garden vegetables where the economy of growing it yourself is obvious; after all, the price at the grocery store is pretty outrageous most of the year!
Most gardeners start an asparagus patch by purchasing crowns two year old root clumps. This is the fastest way to get a harvest. Lately, though, more seed merchants are carrying seeds as well. Seed is typically a more economical way to establish an asparagus bed, plus there are a wider number of varieties available from seed. Additionally, plants started from seed are much less likely to carry some of the diseases that can plague asparagus, such as fusarium or rust.
Asparagus seedlings can be somewhat touchy about transplanting. For this reason, it's better not to start it in a community flat. Instead, sow seed into individual 3-4 inch pots (peat pots are best), with about ¼ inch of soil over the seed. Bottom water until the top of the soil is visibly moist, then remove the water and let them drain for at least 15 minutes. Next move the pots to a warm spot, preferably at around 70F. Since the seed will take some time to come up (usually 2-3 weeks in warm conditions), it's a good idea to cover them with clear plastic so they retain their moisture. Another option is to seal them in Zip-Loc bags.
Whether you purchased crowns or are starting your own seeds, the bed should be prepared well ahead of transplanting time; during the previous fall if possible. Add several inches of compost or well-rotted manure on top of the row (or bed, depending on how you are going to arrange things). If the soil is very acid (pH below 6.0), add lime as well; asparagus prefers a pH in the range of 6.0-6.7. Work the whole mess into the top 12 inches of soil. Good winter drainage is critical, so locate your asparagus patch carefully. If you live in a soggy location (such as my home, western Washington), consider building a high raised bed.
Purchased crowns should be transplanted early after the danger of hard frost, but before the crowns break their dormancy. Seedlings, on the other hand, shouldn't be set out until after your last usual spring frost date. In either case, when you are ready to transplant, add about 2 cups of a complete organic fertilizer for every 10 row feet (chemical recommendations are 3-5 pounds of 5-10-10 per 100 square feet of bed) and work it into the soil. Next you need to dig a trench: If you are in a cold climate (USDA zone 6 or below), dig down 8-12 inches in the spot where the row is desired. For milder climates a more shallow trench is needed, only 2-4 inches. The plants/crowns should be placed at the bottom of the trench, 12 inches between plants in rows 2-4 feet apart; if using crowns, spread the roots as evenly as possible. Cover with 1-2 inches of soil, and water them in to make sure you don't have air pockets.
As the plants grow over the next few weeks, push more dirt back into the trench until it is level with the surrounding soil. As you do this, though, be sure not to completely cover the growing points of the plants.
For that first season (two seasons if starting from seed), no harvest should occur. You should, however, fertilize (at the same level as before) in late spring. The following season you should only harvest spears for a week or two, and then let them grow. After that, a good rule of thumb is to harvest until the larger new spears are no bigger around than a pencil; then leave the plants alone. Asparagus is a heavy feeder, and will need to be fed twice: Once when the plants are just breaking dormancy, and again when you are finished harvesting for the year. The plants may take 5-6 years to reach maturity, but your patience will be rewarded mature asparagus plants can often be harvested for up to 8 weeks!
It is best to harvest asparagus spears by hand, breaking them off near the soil level. Knives can be used, but be careful not to damage neighboring spears; otherwise they may rot.
Once you stop harvesting, the spears grow into quite beautiful ferns. On good soil these can get 6-7 feet tall. The ferns should be left alone until killed by frost, then removed. In cold-winter areas, the ferns can be left until spring; their fronds help catch and hold snow, which somewhat insulates the root crowns.
Asparagus is bothered primarily by two pests. Slugs love to chew on young asparagus, so bait or traps are a good idea. The Asparagus Beetle enjoys dining on the mature ferns. These can be hand-picked, or controlled with 5% rotenone (a botanical poison).
Older varieties like Mary Washington are rapidly being supplanted by new hybrids, most commonly the all-male Jersey Knight (also called Jersey King). This variety was bred at Rutgers for high yields, cold tolerance, and disease resistance. UC-157, developed at the University of California at Davis, is a superior asparagus for areas with fairly mild winters. My personal favorite for yield and taste, though, is the very pricey French variety Larac.
North Carolina State University has some good detailed cultural information for the home gardener growing asparagus. You might also want to read this article by Carol Savonen, of Oregon State University's Cooperative Extension. Of course I can't resist linking to Territorial Seed Company's asparagus page, since they're the only vendors I know of who sell Larac.
Okay, I've been avoiding this one, but I know SOMEONE will bring it up, so here's a page explaining why asparagus can make your urine smell bad. Don't shoot the messenger!
All contents © Travis Saling
This page was last updated July 9, 2011