DearAggie: Grow asparagus and be rewarded year after year

Planting asparagus is straightforward. The first step is to select a site with well-draining soil and full sun. Avoid are wet or water-logged locations. Asparagus also needs full sun — so avoid the north-side of homes or locations under trees. Remember that asparagus is perennial. With proper care, asparagus plants can live for 20 years. Mature plants also transplant poorly — so select a location where the plants can be left for years to come. Thankfully, asparagus tolerates a wide array of soil pH and will perform well in the alkaline soils common around Watertown. It’s deep root system makes it tolerant of dry soils and locations without irrigation (though watering is recommended in the first year). Hardy to an incredible Zone 2, it is cold-hardy everywhere in the north country (Zone 4). Because it is native to seaside locations in the Mediterranean, asparagus will even tolerate road-salt, allowing it to be planted near sidewalks and roadways.

While asparagus can be grown from seed, gardeners will have the best success by purchasing crowns — bareroot asparagus roots shipped in dormancy. These can often be found at garden centers and nurseries. Especially when you plan to buy a larger quantity of crowns, we recommend buying from a catalog and having them shipped mail-order in early spring. That way, they will be in cold-storage right up until the day they are shipped (as opposed to sitting in on the shelf of a retailer, which tends to dry them out). A variety that I recommend for Northern New York is Millennium, which is rarely available at local retailers but common in mail order catalogs. This variety performs well even in heavy clay soils. An interesting novelty variety for our area is Purple Passion.

To plant asparagus crowns, start by digging a trench about 10 inches deep and 12 inches wide. Spread a 2-inch layer of compost or well-rotted manure into the bottom of the trench and turn it into the soil with a spade. This will help improve the soil fertility and promote healthy roots. Once the trench is ready, it’s time to plant the crowns. Place the crowns in the trench, spacing them about 18 to 24 inches apart. Gently cover the crowns with soil, and firm the soil with your hands. Water the asparagus bed generously, and then cover the bed with a 2-inch layer of mulch. The mulch will help retain moisture and keep the weeds down — critically important during the first year or two as plants become established.

Asparagus plants need time to become established before they can be harvested. The first year, refrain from any harvest whatsoever. I recommend avoiding harvest in the second year, though some growers do pick lightly from their plantings at that time.

In the third year, you can begin harvesting spears from about May through June. Pick the spears when they reach about 7 inches tall. Stop picking in about mid-June to allow some of the spears to develop into fronds. This fern-like foliage can then gather and store energy during the summer for next year’s harvest. Though established plantings can survive drought, water them during dry periods to ensure a good harvest. To minimize weeds, add a 2-inch layer of mulch every spring. Be sure to remove any weeds from the patch, particularly perennial weeds, as these will tap energy from your plants.

Written by Mike Nuckols, Cornell Cooperative Extension, agriculture and natural resources team leader.