Plant Asparagus this Spring for Next Year's Harvest

Date:  March 17, 1997
Editor: D'Lyn Ford  (505) 646-6528, dlford@nmsu.edu

LAS CRUCES -- Although asparagus grows wild along New Mexico's ditchbanks, it produces the best spears in a well-fertilized garden.

Once established, a properly maintained asparagus bed will produce for 10 to 15 years.

"Asparagus is generally started from year-old crowns," said George Dickerson, horticulture specialist with New Mexico State University's Cooperative Extension Service.

He recommends planting in a trench 1 foot wide and 1 foot deep that has been backfilled with a mixture of soil, compost and superphosphate fertilizer until it's about 8 inches deep. Crowns should be placed 12 to 18 inches apart with spears pointing up, covered with a 2-inch layer of soil and then watered.

No spears should be harvested the first year, allowing the plants to form ferns.

"Good fern growth is essential the first year to ensure maximum carbohydrate accumulation in the roots," Dickerson said. Strong, well-nourished roots will make for healthier, higher-yielding asparagus, he said.

As ferns develop, backfill with soil and compost, forming a raised bed of ferns and enriched soil.

"Spears can be harvested the following spring with a knife or by snapping them off at the soil surface. Stop harvesting when the average spear is less than a quarter-inch thick," he said.

Allowing the plants to develop ferns at this point will replace the carbohydrates in the roots for next year's crop. Ferns can be removed during the winter.

Dickerson recommends planting newer all-male hybrids like 'Jersey Giant.' Because they don't form seed pods, conserving energy for spear production, these varieties are higher-yielding than traditional types like 'Mary Washington.' The new hybrids also are more resistant to diseases such as fusarium wilt, he said.