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ASPARAGUS IS EASIER TO GROW AND MORE PROFITABLE THAN EVER
BY BOB HOFSTETTER
For years kids and growers felt the same asparagus: 'Yuk!" Kids tastes haven't changed. But growing asparagus has. New management practices, earlier harvest and higher-yielding varieties have made this perennial more lucrative than ever.
Many growers are giving asparagus a second chance, much to the delight of dedicated customers who wait with open arms--and open wallets--for each season's harvest.
"It's like the end of cabin fever. Asparagus is the first thing that's green and good for you every spring. People gobble it up," observes John Sedlock, Swedona, Ill., who grosses $8 per pound on some value-added asparagus products. (See sidebar "Hooking A Town On Asparagus" on page 26.)
Sedlock started with 1 acre of. asparagus in '85, and added more every few years. He stopped at 8 acres because he says that's all he rued lids knife, Pat, can manage properly. 'You should begin at no more than half an acre," Sedlock suggests.
But even half an acre can be a challenge if you follow tile "old" principles of asparagus production. Studies in recent years have shown that some tedious production chores--which many growers still follow religiously--are completely unnecessary even for a bumper crop.
Myth: Set year old roots (called crowns) bud-face up in a furrow, at least inches deep.
Reality: "It doesn't matter if the crowns are right-side-up or upside down," says Carl Cantaluppi, research and Extension horticulturist at Ohio State University. "Furrows should be no more than 6 inches deep and spaced no more than 6 inches deep and spaced no less than 5 feet apart. Deeper-planted crowns produce less."
Myth: At different growth stages, put soil back into furrow without covering the asparagus foliage.
Reality: "Drop the crowns into the furrow at 18-inch intervals. You can completely refill the furrows to soil level without damaging the crowns. But don't compact the furrow soil, because it will severely delay or reduce spear emergence," says Caultaluppi, whom growers call the "asparagus guru." The good news: You only have to plant every 10 or 15 years-- the life expectancy of productive stand.
Myth : Forget about harvesting any asparagus until the third year after planting.
Reality: If you start by planting year old crowns, you can harvest the following year. "It was always assumed that if you began harvesting asparagus the year after the crowns were planted, it would weaken the crowns' ability to store food reserves, which would cause dramatic reductions of future yields," says Cantaluppi. "However, during the past 10 years, researchers in California, Oklahoma and Illinois found that harvesting one year after crown planting had no effect on subsequent yields."
Most growers buy the crowns. "Unless you have 20 acres or more, the easiest and most popular method to establish a planting is to purchase year-old, certified disease-free crowns from a reputable grower," recommends Cantaluppi. Growers with larger asparagus acreage often direct seed or start their own transplants in greenhouse flats, although labor and production requirements are high. It also delays harvest one year.
Myth: Yields are knew all asparagus varieties.
Until the late '80s, no one could dispute that. But all-male hybrids can double--or even triple--the yields of the common open-pollinated MARY/MARTHA WASHINGTON varieties with half as many plants! Because they don't produce seed, these improved varieties expend ad their energy on spear production. Based on a 5- to 6-foot row width, you'll need only 4,800 to 5,800 crowns per acre compared with the 8,000 to 10,000 recommended for open-pollinated varieties.
You can find the Rutgers University developed all-male hybrids, such as JERSEY KNIGHT and JERSEY GIANT, at selected outlets. (See "Sources" on page 28.) 'the New Jersey hybrids have been tested all .across the U.S. and are widely adaptable. They even outyielded California varieties. Under hot growing conditions, however, spears have to be harvested at a shorter height," says Cantaluppi.
Don t misunderstand me: Even if you follow the new production techniques, growing asparagus is still no picnic-- especially if you're doing it organically.
"If there was ever a crop that wasn't conducive to organic production, it's asparagus," says Sedlock.
But if you're up to the challenge, the premiums you receive might be worth your patience. Your first--and worst-- battle will be with weeds.
You need excellent preplant weed control at least one year before planting. 'You must eliminate perennial weeds before planting asparagus crowns," says Richard de Wilde, a certified organic vegetable grower in Viroqua, Wis. If you aren't using non-selective herbicides, a combination of tillage and cover cropping should get you off to a good start.
A good regime for established beds includes a shallow early dishing followed by hand-pulling, hoeing and mulching with clean straw or compost. But it's tricky to maintain good weed control, because even the shallowest cultivations can reduce yield and the longevity of the planting. "Growers not using herbicides will have to take that risk," says Cantaluppi.
De Wilde did. "I carefully cultivated during the establishment year and had excellent weed control," says de Wilde, who harvests 3,000 pounds of spears from his 1-acre planting. "During production years, I disk or rotovate early in spring no more than 1 to.2 inches deep. To lessen damage to the asparagus crowns, I keep the tractor wheels off of the rows. I broadcast annual ryegrass at about 25 pounds per acre right after rotovating. It grows slowly and doesn't seem to lower speak yield or quality. When asparagus harvest is over, the ryegrass is only a few inches tall."
Although ryegrass helps suppress annual weeds, you'll still have to hand weed. Expect aggressive perennial weeds to sneak into the planting and lower yields. "Because of eventual heavy weed pressure, and the time anti labor required to keep an old planting clean, I can t keep a planting profitable for more shall 10 years," says de Wilde, who sells out of his $2.50-per-pound asparagus at a Madison, Wis., farmers market.
If weed control hasn't drained all your energy, the next step is maintaining proper soil conditions. Asparagus needs welldrained soils and performs best on sandy loams. It demands a pH between. 7 and 7.0. And make sure the soil temperature at planting is above 50 F.
For optimal yield, you want high soil test values--at least 250 pounds per acre of phosphorus, and 300 pounds per acre of potassium--says Cantaluppi. At planting, add 70 pounds of nitrogen per acre, he advises. Studies show asparagus doesn't respond to additional N in subsequent years. Monitor P. K, and pH levels at least every two years.
Compared with weed control, harvest should be a snap. Harvest when the heads are tight and before the tips start to open (fern out). During cool weather, fiber develops slowly in the base of the spears. They can grow to about 9 or 10 inches before ferning out.
You can snap or cut asparagus. Snapped asparagus breaks the spear off above the fibrous area. Harvest this way for immediate sale because the spears are table-ready. Although it's more time-consuming, you'll need to cut asparagus at or below the soil line when shipping. These spears still have a tough, fibrous base that reduces moisture loss.
"During cool periods, you'll need to harvest only two or three times per week," advises Cantaluppi. "But when it's wane, you'll have to remove the rapidly growing spears daily and at a shorter length. Remember to get rid of curved or damaged spears and fern growth because they can harbor insects and disease."
Depending on temperature, you'll be harvesting for about two to three weeks the first year after crown planting and about four to six weeks in subsequent years. "Spear thickness is actually a better indicator than the number of weeks," says Cantaluppi. "As harvest winds down, spear thickness decreases. Stop when 75 percent of the speaks are three eighths inch thick or less--the diameter of a pencil."
Don't try to extend the harvest period. "Over-harvesting will weaken the crown by decreasing the stored carbohydrates. This reduces yield and the planting's longevity," Cantaluppi warns.
Plan ahead to minimize any conflict between asparagus harvest and your other production chores. "Depending on growing conditions, asparagus is ready to harvest and market from late April to early June, the same time I have to get my remaining 7 acres planted to other vegetable crops," warns Illinois grower John Sedlock.
If all goes well, you can expect about 500 pounds of asparagus per acre the first year after planting year-old, all male hybrid crowns. In a well-managed planting, yields should increase about 1,000 pounds per acre each yeah until they level out at 4,000 to 6,000 pounds. De Wilde's certified organic plots average 3,000 pounds for a gross of $7,500 per acre. That's a good return for your labor.
So forget what the kids think. Stick with the grown-ups--they'll buy so much asparagus you'd think it was chocolate-covered. Wait a minute, even the kids might like that.
Editor's Note: "Dr. Bob" loves to eat asparagus. But he refuses comment on when he'll start planting it on his high value farm in Limeport, Pa.
Copyright © 1994