Wednesday, April 23, 2008

Growing Asparagus

What can you do to cure the winter blues? You can think of sunshine, longer days, warm breezes, and succulent spring asparagus.

Asparagus has long been a harbinger of spring. Protected by an old fence line dividing our yard from the neighbors, hidden behind an ancient lilac bush, lingered an old asparagus bed that had been planted by my great grandfather. When winter had pasted and the sun warmed the ground little buds would poke through the soil sending their tender shoots skyward. We passed the asparagus bed each morning on our way to the bus stop and when the shoots were about six inches high my mother would come forth with a big basket for carrying her bounty back to the kitchen.

That house is gone from my family now. I imagine if no one found the hidden spot that the asparagus grew until the stalks were tall and tough, a feathery crown reaching skyward. Since it is still one of my favorite vegetables and so easy to cook in so many ways I decided to plant a bed at my own home.

Asparagus grown in your own garden is tastier and much less expensive than any you can get at the grocery store or at a gourmet restaurant. Once you have eaten your own fresh asparagus after you have harvested it from your own garden, you'll never go back.

It is important to realize that the work that goes into establishing an asparagus bed doesn't pay off in good eating for several years and will take a bit of work. However, asparagus is a perennial vegetable, once established it keeps coming back and getting better year after year. A good asparagus bed can truly last a lifetime with minimal work once it has been well established.

Go Ahead, Get Growing

The best time to begin digging and preparing your asparagus bed would be in autumn, but don't wait another season; go ahead and start as soon as you can.

To have a fine bed of asparagus, plan carefully. If you haven't had a recent soil test, you should get one, knowing what the pH of your soil is will save you a lot of difficulty and help your asparagus bed properly establish itself. Soil pH should be maintained between 6.5 and 6.8. Asparagus does poorly at pH levels below 6.0.

Choose a site with good drainage and full sun. The tall ferns of asparagus needed to help establish a strong root system may shade other plants, so plan accordingly. Properly preparing your bed is equally important. If your soil is heavy or full of clay you will need to incorporate generous amounts of well decomposed manure, organic matter such as compost, and maybe even a little sand.

Early in spring when you can work the soil without it clumping (if the soil is too wet, you will end up with hard clumps of earth) dig your trench add your fertilizer, lime, if needed, and organic matter as needed. In heavy soils, double digging is recommended. To double dig, remove the top foot of soil from the planting area. With a spading fork or spade, break up the subsoil by pushing the tool into the next 10 to 12 inches of soil and rocking it back and forth and digging a V-shaped trench. Do this every 6 inches or so. Double digging is ideal for the trench method of planting asparagus since a 12-inch-deep trench is usually dug anyway. The extra work of breaking up the subsoil will be well worth the effort, especially in heavy soil.

Asparagus, a member of the lily family, is just about impossible to grow from seed but you can easily purchase 1-year-old asparagus crowns, which are the roots of the plant. Look for bundles with 10-15 roots that are dormant (showing no green shoots) that look firm and fresh, not limp. The bundles can be obtained from a local plant store, nurseries, mail order catalogs or sometimes your local hardware store. Just time your purchase accordingly because you should plant as soon as possible after purchasing.

Asparagus requires lots of space. Crowns should be planted every foot or so in rows 4 to 5 feet apart. Place the plants in a trench 12 to 18 inches wide and a full six inches deep. The crowns should be spaced 9 to 12 inches apart. Spread the roots out uniformly, with the crown bud side up, in an upright, centered position, slightly higher than the roots.

Cover the crown with two inches of soil. Gradually fill the remaining portion of the trench during the first summer as the plants grow taller, but do this a little at a time until you are eventually at “ground” level again. Asparagus has a tendency to "rise" as the plants mature, the crowns gradually growing closer to the soil surface. Many gardeners apply an additional 1 to 2 inches of soil from between the rows in later years.

You’ll also want to give new plantings one to two inches of water a week; after that, water only when rainfall is scant. Weeds and grasses are asparagus’ worst enemy. They compete with the developing spears in your garden and can significantly decrease yield and quality. Start frequent, light, shallow cultivation early in the spring in both young plantings and mature patches that are being harvested.

Asparagus produces both male and female plants. The female plants are pollinated by the blooms of the male plants and produce red berries in the fall. The berries contain seeds that self-sow. The list of commonly available varieties has significantly changed in recent years. Standard varieties like Mary Washington, Martha Washington and Waltham Washington are still being offered; but a number of new varieties that are either predominantly or all male recently have been introduced in to common usage.

Many gardeners recommend that you select the new all-male hybrid asparagus varieties such as Jersey Giant, Jersey Prince, and Jersey Knight. These varieties produce spears only on male plants. Seeds produced on female plants fall to the ground and become a seedling weed problem in the garden. Female plants also have to expend more energy to produce the seeds that decreases the yields of asparagus spears on female plants. The all-male hybrids out-yield the old Mary Washington varieties by 3 to 1. Since I like things natural and productive I think a mix of both male and female can be used and easily maintained. I also believe it will add length of life to my asparagus bed. It’s nice to think that after I have moved on someone else will be able to enjoy the fruits of my labors for many, many years.

Once your bed is set it should be fertilized in the same way as the rest of the garden the first 3 years. In the spring, apply 10-10-10, 12-12-12 or 15-15-15 fertilizer at the rate of 20 to 25 pounds per 1,000 square feet of area or 2 pounds per 100 square feet and incorporate gently till into the soil. Starting in the fourth year, apply the same amount of fertilizer but delay application until June or July (immediately after the final harvest). This approach encourages vigorous growth of the "fern," which produces and stores nutrients in the roots for next year’s production season.


Refrain from harvesting any spears during your plants' first year in your garden. Each spear needs to "fern out" so that the roots can grow stronger and more productive. The second year you can pick a few that reach about the size of your index finger; the third year, pick finger-size spears for two to four weeks in the spring. In subsequent years, take all the finger-size spears you want until the spears that come up are thin and spindly.

Use a knife to harvest spears. Use one hand to hold the top of the spear you are harvesting. Cut the spear off about one inch below the soil line. Be careful not to cut too deep - it will damage the asparagus crown. Harvest all the spears that come up during the harvest season. A good general rule for length of harvest season is the 2-4-6 week sequence. Harvest for 2 weeks the second year the plants are in the garden, 4 weeks the third year, and 6 weeks the fourth and all following years, each succeeding fall, remove any brush after it has turned brown.

If you harvest asparagus that not be used immediately, wash the spears and place the cut ends in about 2 inches of water. This way they will keep in the refrigerator for several days.