Asparagus is traditionally harvested using the “clear cut” method – for a few weeks each spring all spears are harvested as they emerge. The harvest continues until food reserves stored in the root system become exhausted – at that point spear diameter begins to decline. If harvest continues beyond this point, the long term vigor of the crop is compromised. The traditional clear cut harvest method results in a glut of asparagus early in the season which can exert downward pressure on prices. An alternative approach to harvesting asparagus is the “Mother Stalk Method”. This method is widely employed in Asia to shift the asparagus harvest season. In the Mother Stalk Method, the first 3-5 spears to emerge in the spring are allow to grow into full size ferns. These ferns then begin to supply the root system with the food reserves required to safeguard the long term health of the crop. All subsequent spears are harvested – shifting the traditional spring harvest period into summer and beyond. Research (Dufault and Ward 2005; Orton et al 2008) suggests that the Mother Stalk Method produces yields that are comparable or even superior to the traditional clear cut method. However the Mother Stalk Method of culture also requires substantially more labor, as harvesting spears from within a developed canopy is difficult If the resulting off-season harvest commands a premium price the additional harvest effort may be worthwhile.
Source : Dufault and Ward (2005). HortScience 40: 1327-1332. Orton, Garrison and Garrison (2008). HortSciennce 43: 595.