How To Grow Asparagus
Plant Type: Perennial
Scientific Name: Asparagus officinalis
Light: Full Sun
Soil Type: Well drained, light & high in organic material
Soil Temperature: 50°+
ph Range: 4.5 – 7.0
Plant (Payson): April 1-30
Planting Method: Seeds or plant crowns
Germination (days): 8 to 14
Transplant: 1 or 2 year crowns
Maturity: 2 to 3 years
Common Pests: Asparagus Beetles
Common Diseases: Fusarium wilt
Asparagus plants are monoecism—meaning each individual plant is either male or female. Male plants yield more shoots because they don’t produce seeds. Some varieties of asparagus, such as Jersey Knight and Jersey Giant, produce all male or primarily male plants. Heirloom varieties like purple-stalked Purple Passion are also available.
Asparagus likes loose soil that drains well and is enriched with aged manure or compost. A properly prepared bed will support your Asparagus garden for many years, so take the time to do it correctly.
Choosing a site for your asparagus bed takes planning—once established it will occupy
the same space for 20 years or more. Asparagus prefers a full sun location to produce vigorous growth and for disease prevention. Asparagus does best in well-drained lighter soils that warm up quickly. Prepare a planting bed by removing all weeds and add lots of aged manure or compost. After selecting the location for the bed, dig a trench, then
Click Here for a detailed illustration on how to plant asparagus.
Buy crowns from a reputable nursery that sell fresh, firm, disease-free roots. Plant them immediately if possible; otherwise, keep them moist until you are ready to plant. Soak the crowns in compost tea for 20 minutes before planting. Place the crowns in your trench 1 ½ to 2 feet apart and cover with 2-3 inches of soil. Two weeks later add another 1 to 2 inches of soil and continue adding soil periodically until trench is filled.
It takes patience to start asparagus from seed. In cold climates start seedlings indoors in February or early March. Sow a single seed in pots, place the pots in a sunny window, and use bottom heat to maintain the temperature of the mix in the pots at 77°F. Once the danger of frost is past, plant the seedlings (which should be about 1 foot tall) 2 to 3 inches deep in a nursery bed. When tiny flowers appear identify female plants (Female flowers have well-developed, three-lobed pistils; male blossoms are larger and longer than female flowers). Weed out all female plants. The following spring, plant the male plants in permanent trenches.
Do not remove plant foliage after it has died back in the fall, add mulch to provide protection during winter months. Remove the fern-like foliage in spring before new growth appears to prevent disease and pests.
It is important to keep asparagus beds weed-free. Mulching will help with this but when you mulch use materials that will not become a problem later. Mulches that may re-generate from seeds should be avoided. Compost, aged manure, or wood chips provide a good mulch. As the compost or manure decomposes it will provide nutrients for your Asparagus plants.
Water regularly during the first 2 years. Asparagus should be kept moist but not soggy for best results. Water in winter, in our area, if sufficient moisture does not occur.
These plants won’t need much fertilizer- just a yearly top dress of manure or compost will do. Or you may fertilize in spring and fall by top-dressing with liquid fertilizer (such as compost tea) or side-dressing with a balanced organic fertilizer or aged manure.
Asparagus and weeds don’t mix. Weeds rob the asparagus of the nutrients it needs to establish a strong healthy plant that will produce delicious spears over a very long time. Planting annual rye grass may help with keeping the weeds down. It will die back in the winter which will help protect the bed but will still be easy to clear away when the new spears begin to emerge in the spring. You may have to hand pull the weeds in your bed so get them while they are small to minimize disturbing the roots of the asparagus plants. Cultivating with tools is not recommended to avoid damaging the growing spears.
Fusarium wilt, causes spears, leaves, and stems to be small with large lesions at or below the soil line. Prevention is the best approach to eliminating this disease. Purchase disease-free crowns and practice good garden maintenance by good water drainage and keeping soil PH above 6.0.
Asparagus plants need to establish roots for a few years before you should do any harvesting. Yes it’s very tempting. But don’t harvest any spears during the first 2 years because the plants need all their energy to establish deep roots. Asparagus shoots are sensitive to frost so cover when freezing temperatures are predicted. You may begin to harvest asparagus in the third year as the young shoots begin to appear.
During the third season you may begin to pick the spears over a 4-week period. Harvest spears every third day or so until the weather warms, at which time you may have to pick twice a day to keep up with production.
Cut asparagus spears with a sharp knife or snap off the spears at, or right below, ground level with your fingers. Be sure not to harvest until spears are 7 to 9 inches tall and only harvest in the cool evening or early mornings. Note: if you want white asparagus you will need to keep the asparagus shoots covered with soil to prevent exposure to light to keep them from turning green.
Asparagus is best eaten fresh. Steaming until just tender results in tasty but not mushy asparagus. You may freeze or can the spears and pickled Asparagus spears are delicious.