The proper time to harvest is determined by the size of the plants, the thoroughness of blanching, prices and the weather conditions. The market will sometimes pay better prices for very early celery, partly blanched and two-thirds grown, than for late, fully matured, perfectly blanched stalks.
Except in the very large commercial plantations the usual method is to lift the plants with a spading shovel or a fork. Some growers prefer to cut the roots at the proper depth with large, sharp butcher knives, a plan which is especially satisfactory in sandy or muck soils and when the crop has been blanched with boards. In the great producing sections, machines are employed to cut the roots. The machine is a very simple device drawn by two horses. It consists of a U-shaped steel cutter 5 or 6 inches wide and 1/2 inch thick mounted beneath and between two wheels. The blade is adjustable, so that it may be set at any depth. When in operation a row is loosened as fast as a team will walk.
It is customary to remove the worthless outside leaves before hauling to the packing shed, where the plants may receive further and more careful trimming. The roots are also cut as desired (413) in the field. The plants may be placed on trays or in boxes preparatory to hauling to the packing room. Whatever plan is used exposure to the sun and the drying air of the field should be as brief as possible.