Gardeners Helping Gardeners Succeed
Planting an Asparagus Bed
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Text by Janet
Illustrations by Elayne Sears
Reprinted from Horticulture
An Asparagus bed, once established, can be counted on to
deliver dependable spring harvests for many years. This perennial
planting also lends a soft, fern-like haze to the edge of a garden. The
easiest way to start asparagus is to set out year-old dormant crowns in
early to mid spring; these are sold at local nurseries or through
mail-order suppliers. Plants you raise from seed will take an extra year
to produce a harvest.
Choose a well-drained site in full sun or partial shade, keeping in mind
that its placement will be permanent; don't put it in the way of yearly
tilling. To determine the size of your asparagus bed, figure that each
mature plant will produce 15 to 20 spears a season, and that each plant
requires 12 to 18 inches of row space. Since asparagus roots are
wide-ranging, allow four to six feet between rows of asparagus, as well
as between asparagus and other crops.
Prepare the Soil
Start by completely removing the weeds -
once the bed is established, it's difficult to get rid of weeds without
harming the roots. Then dig a trench eight to ten inches deep and about
12 inches wide. Pile the excavated soil to one side; you'll use it later
to cover the growing plants. Sprinkle in a complete fertilizer that is
high in phosphorous and potassium (to promote vigorous root growth), such as
a 5-10-10 formula, applying two pounds to each 25 feet of row. Also, add
lime if the pH of your soil is below 6.8 - asparagus does not grow well
in acid soils. Finally, dump in a couple of inches of compost or
well-rotted manure and dig all the amendments into the bottom of the
Plant the Crowns
Mold the soil in the trench into small
mounds, spaced 12 to 18 inches apart. Set a crown on each mound with it
top - the side with buds - facing upward and gently spread out the roots. Cover the
crowns with two inches of your reserved soil, leaving the rest to fill
the trench later on. Water well.
Gradually Fill the Trench
The first shoots should appear within a
couple of weeks. As they grow, fill the trench a little at a time with
your reserved soil. By the end of summer, the trench should be filled in
at a level even with or slightly higher than the surrounding soil.
During the first growing season, let all of the shoots
leaf out to nourish the roots. Give the plants an inch of water each
week if it doesn't rain, and pull any weeds at they appear. Once the
trench is filled in, mulch the plants with salt hay or leaves.
In the fall, the ferny growth will brown. In regions with cold winters (USDA Zone 5 and colder), leave the dried
stems in place to catch the snow, and plan to cut them in the early
spring before growth resumes. In milder climates, it's better to remove
the ferns to avoid carrying over foliar diseases. In all climates,
topdress the bed in the spring with aged manure or compost.
Gardeners used to wait two full years to make their
first harvest. However, research has shown that a light harvest in the
spring the year after planting does not harm if you limit it to a couple
of weeks. The next year, you can extend the harvest to four to six
weeks, and even longer -- up to eight weeks -- in the following years. To harvest, use a sharp knife to cut just below
the soil, or use you fingers to snap off the spears when they are five
to nine inches long.
If emerging spears are thinner than a pencil, stop harvesting. It's time
to allow the foliage to grow again, to provide nourishment for future
Older asparagus varieties,
such as 'Martha Washington' produce both male and female plants. The female
plants are less desirable because they put their energy into making seeds, which
reduces their spear production, and overpopulate the bed with volunteer plants.
Recently, researchers at Rutgers University have introduced several highly
productive, all-male hybrids that also have tolerance to asparagus rust and
fusarium crown rot. Adapted to most climates, these include 'Jersey King',
'Jersey Giant' and 'Jersey Knight'. A good choice for warmer areas (Zone 5 and
above) is predominantly male 'UC 157', which produces spears even when harvest
weather is hot. 'Purple Passion' is deep purple in color, it grows well in all
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