E.A. van Os, L. Simonse
Climate limits the possibilities for extending the harvest period of field-grown vegetables. However, crops that store assimilates during summer can be forced in winter: year-round production of chicory is already possible.

The harvesting period of asparagus (Asparagus officinalis L.) is short, requiring a large workforce to work under unpleasant conditions. The feasibility of forcing this crop under conditioned climatic circumstances in winter has therefore been investigated, resulting in the following method for forcing asparagus in water:

Asparagus crowns are grown outdoors for several years before being lifted and placed in containers that are then stacked four to eight high in a climate-controlled chamber in total darkness. Water in circulated through the containers, returning to a reservoir to be enriched with oxygen and reheated. Harvesting starts within 10 days after installation, and continues for more than 20 days. The plants are then removed and replaced by new ones.

Research has been done on the technical equipment required and on the economic prospects of this method.

The growing and forcing of asparagus plants on rockwool has also been studied.

van Os, E.A. and Simonse, L. (1988). FORCING ASPARAGUS IN WATER. Acta Hortic. 221, 335-346
DOI: 10.17660/ActaHortic.1988.221.37

Acta Horticulturae