Asparagus A long term investment!
A well prepared, well cared for asparagus bed can be productive for ten years or more!
Choose a permanent location with well-drained soil in full sun. Don’t plant too early in the spring because frost will kill new shoots.
It is best if you prepare the site a year in advance. Remove all perennial weeds. Have a test done to be sure the soil is in the correct pH range
and that it contains high levels of phosphorous. An application of lime may be needed to adjust the pH. If the phosphorous level is low, we recommend bone meal (½ lb. per 10’ row) or super phosphate. Spread phosphorous and lime thoroughly at the bottom of the 8” deep planting
furrow. For heavier, clay-like soils, 6”-8” deep furrows are recommended. Planting crowns too shallowly encourages early spear emergence,
higher probability of frost injury and greater possibility of winter kill of crowns. In the early spring, at least 2-3 weeks prior to planting, incorporate 5 lbs. of 10-10-10 per 100 sq. ft. If you have not fertilized 2-3 weeks before your planting day, side-dress several weeks later when the
plants are growing well.
Lay roots along the bottom of the furrow and cover with 2”-3” of soil. Roots are planted horizontally, parallel to the bottom of the trench and the
soil surface, not vertically like strawberry plants. Do not add fertilizer or compost until plants are growing. Irrigate well after planting. As the
spears grow up and expand into fern, gradually fill in the trench with soil. You may mix up to 50% well-aged compost into the soil or add 1 lb.
10-10-10 or equivalent balanced fertilizer into the soil as you fill the trench. Within six weeks, the furrow should be completely. Using this method helps to limit weed development. You may wait until all the ferns are growing above the trench and fill the trench at one time.
Plants need a well drained site. Maintaining moisture during the establishment year is very important. Lighter soils may require more frequent
watering than heavier soils, which retain moisture better.
Establishment year: Do not add compost or fertilizer until plants are growing. After plants have started to grow, fertilize during the period the
trench is being filled. You may mix up to 50% well aged compost into the soil or add 1 lb. 10-10-10 or equivalent, balanced fertilizer into the soil
as you fill the trench. Side-dress in early August with 1 lb. of 10-10-10 per 100 sq. ft. (or equivalent) and lightly work into the top 2” of soil. Succeeding years: Use 2 lbs. 10-10-10 per 100 sq. ft. in early spring and again following harvest. To maintain optimum soil condition, test your soil
pH every 3-4 years and amend as necessary. Broadcast lime, bone meal, and super phosphate according to soil test results and recommendations, keeping the pH above 7.2.
Weed Control & Mulching
During the harvest period, manually pull weeds so emerging spears are not injured. Ferns will die back naturally in the fall. Mulching the dried
ferns with a mower in the spring will reduce weed pressure. Check with local extension before using chemical products. If tilling the soil during
the rest of the growing season, only till ½”-1” of the soil surface. Deep tilling can damage your crowns
and bring weed seeds up to the surface.
Control weeds all season and irrigate as needed. Be on the lookout for asparagus beetles and their larvae, aphids and the asparagus miner.
These insects can cause serious damage to an established bed. For chemical weed and pest control recommendations, contact your local Cooperative Extension office. Do not remove or cutany ferns during the growing season. Cut the old ferns down to ground level in the early spring
before new spears begin to emerge.
Research shows that you can begin to harvest asparagus the year after establishment. Cut or snap all 5″-8″ spears that appear for a period of 7
-10 days. Make sure you cut or snap stalks close to the soil surface, not leaving stubs. Stubs can be potential entry points for pests and diseases. Be careful not to damage emerging spears when cutting spears below the soil surface. When spears begin to get spindly, stop harvesting
for the season and allow all new spears to develop into ferns to feed the crown. The second
season, you can harvest all the spears that appear for a period of 3-4 weeks. By the third
year, you can harvest for the full season, which is usually 6-8 weeks long.
TIPS: (With a little care you should enjoy an asparagus bed for many years!)
• If frosted, tips become brown.
Remove the spear immediately to
prevent further setback of the planting.
• During harvest, asparagus roots
need about 2”-3” of water per week.
Do not let the soil get too dry.
• It is best to incorporate bone meal
or super phosphate into the soil at
the bottom of the planting trench.
• Asparagus grows tall with a fern like foliage which could make an
attractive garden border or backdrop