Grow Your Own Asparagus, A Rare Perennial Vegetable

Asparagus is one of a very few vegetables that needs to be planted only once. Virtually unique as a perennial vegetable, harvests of the tasty spears return year after year—and, yes, they are related to our houseplant the asparagus fern (which is not a fern at all, but a true asparagus that thrives in full sun, not the shade of your darkest corner). The only guaranteed way to really get the tastiest young and tender spears is to grow your own.The edible part is the young shoot, harvested before it matures into a leafy, fern-like stem. It does best in full sun, and because it shades out other plants and doesn’t need seasonal replanting, it should be grown apart from the rest of the veggy garden, usually on the north or east side. This is why the specific part of the garden set aside for this plant is called … the asparagus patch.

As a well-established and productive asparagus bed matures, it may appreciate being thinned, but an asparagus plant will produce delectable spring shoots for 100 years if left perfectly alone. In fact, it can often be found growing in the “wild,” where a gardener or farmer may have planted it generations ago.

But dividing and transplanting will increase the number of asparagus plants and thus the yield. This gives you an opportunity to expand your patch or gift some of it to friends and neighbors.

This is the time to start your asparagus plot. The next few weeks is the time to buy year-old crowns and get them planted. And you can buy them at local garden stores.

Asparagus crowns are sold in garden centers and by mail, and are planted as early in the spring as the soil is workable. Crowns are spider-like clusters of roots measuring perhaps 8 inches in diameter. These are purchased as bare root plants, not in pots or soil but simply bundled with exposed roots in units of about a dozen each. Each crown, distinguished by a cluster of pale green or white knobs that later become shoots, goes into a separate planting hole.

As the plant grows, it spawns new crowns until, eventually, it becomes a whole mass of these root clusters, overlapping each other under the soil surface.

Above the soil, the plant gets larger and fuller over the years, and the harvest of green shoots in May or June gradually grows from a half dozen spears per plant to more than two dozen. Two dozen crowns will be enough to feed two people, so plan accordingly, and if you plan on freezing any, at least double the crown count. Also keep in mind that you can buy all male plants, which are more productive, as the female plants expend part of their energy reserves on producing flowers, which result in seeds.

Depending on the variety of asparagus, the quality of the soil and other environmental conditions, it can take from three to eight years to develop a mature “patch,” but your first harvest should always be stalled until at least the second season after planting. Avoid the temptation to cut the stalks the first year, as letting them grow and mature the first season without being disturbed is critical in establishing vigorous plants with great roots.

New or divided crowns should be planted in deep, rich organic soil by slicing a “V” or wedge into the soil and sliding the crown into the “V.” The crown should sit just slightly below the soil level and the soil filled in around the crown and firmed.

If asparagus plants are to be divided to expand the size of the plot or to share with friends, the best crowns will come from plants that have been in the ground a minimum of three years. The dividing process begins in the fall, as the “ferns” begin to brown.

First, cut back the fern-like foliage to about 6 inches. This will make the plants easier to handle. Don’t worry, the foliage is dying back anyway this time of the year. Next, with a garden fork or sharp spade, define a crisp vertical trench around the plant, leaving a soil area of about 4 inches between plant and trench border.

Next, dig the plant gently with the fork. Some roots will get nicked off in the process, but this will not harm the plant. Once the entire asparagus plant is loose, lift it out of the ground and gently dislodge as much soil from the roots as possible.

The real work begins now, as you untangle the interlocking crowns and roots. Work carefully to minimize trauma to roots. Divisions can contain perhaps three or four crowns, which saves you the trouble of separating each crown. The trade-off will be in fewer new plants. Whether you settle for crown clusters or individual crowns, discard the smallest crowns or combine them with larger ones in the new location.

The planting techniques are the same for expanding old plots or establishing new ones. The new soil should be loamy, well drained, high in organic material and deeply dug. I’ve never met a new asparagus bed that didn’t thrive when the original planting was done with tons of well-rotted (aged) manure.

The soil should be cultivated all around the new plant to a depth of at least 8 inches. The plants can go in individual holes, or you can dig a long trench, but make sure each planting has at least 12 inches of space to itself.

Cover newly divided plantings with soil, and compost and tamp down firmly before you water. Water gently, and the initial watering can contain a biostimulant—but no fertilizer. You can also schedule the project just before rain is expected, then add the biostimulant and cover the whole thing, cropped foliage and all, with a thick mulch of shredded leaves or more well-rotted manure.

If you are overly anxious about your newly planted asparagus, you may be able to snip a spear or two this spring, but it is traditional and sensible to hold off on harvesting until year two. This permits a full flush of foliage to develop during the first season—and it is the foliage that feeds the roots that will provide you with the abundant harvest of year number two and far beyond.

Asparagus beetles are the only potential problem, and if they are controlled early with an organic treatment, they can be quickly eliminated. If allowed to hang around, though, they will be a perennial problem.

Fall care for established asparagus includes intense weeding to remove persistent perennial weeds from the bed. This is topped by a dressing of compost, well-rotted manure (disinfectant-free, if you are going to get some locally), leaf mold or ready-made compost—all of which are excellent—about 4 inches thick, covering the whole bed. Mulch through the winter with leaves, preferably shredded, and you’ll have excellent spears next spring.

Cutting back foliage from mature asparagus is largely a matter of preference. If they are trimmed back, leave a few inches of growth above the mulch line so that you will know where they are next spring.

You can also grow asparagus from seed. The seed can be started indoors in cells in late February and planted in the garden in late April. Germination takes about two weeks, and while it takes an extra year to get a crop, it’s a very inexpensive way to grow lots and lots of plants.

Need more information? Curious about white and purple asparagus? Enter this link in your browser and find out more https://tinyurl.com/z8kgyrl

And, of course, keep growing!