Surfing the Harvest Wave

When I first started growing perennial herbs for commercial sales, we would harvest only the plants that seemed ready, and only harvest what we needed from each plant. When I started paying attention, I realized that we actually did this in varying degrees in a lot of our cut-and-come-again vegetable crops, such as our kale, chard, parsley, and salad greens.

This seemed like the best way to maximize our yields, but in the end, it really just maximized our work as we spent as much time walking and evaluating each plant as we did harvesting. It also resulted in a field that had a patchwork quilt of regrowth size and quality. A chard plant with eight nice leaves would sit right next to one that had been harvested down to its nubs, or a thyme plant would be half-harvested while the other half was going to flower. And pretty soon, some plants were overgrown and woody, while the remaining plants were over-harvested to meet demand.

At the time, we were rotationally grazing sheep, and I had been reading about proper management of pastures in rotational grazing - basically, you keep the sheep (or whatever other ruminants you're grazing) on a given piece of pasture until it has all been eaten down to the best level for managing the target species in that paddock, then move the herd to new section of pasture; and you manage the grazing to prevent the plants from switching from green vegetative growth to reproductive, flowering growth.

I realized that we could apply some of the same principles to growing and harvesting our herbs and vegetables:

1. Harvest everything in a section of the bed to the same level;
   
2. Create a “wedge” of growth;
   
3. Manage plants for vegetative, not reproductive, growth; and
   
4. Manage our “grazing” to match the variable growth rates throughout the year.
   
   

Most of our herbs and greens at Rock Spring Farm were planted as full 150-foot (and later, 300-foot) beds, with two rows per bed, so our “paddock” size was determined by how many feet of bed we harvested for a given day's needs. If the leaves on a plant were too small to harvest, we cut it right back to the same level as all of the harvested plants around it, and simply threw the too-small portions on the ground. The end result was a section of the bed in which every plant had been harvested to the same level: a crew cut on the thyme plants, or every kale plant left with 6 small leaves.

Harvest started at one end of the bed, and moved steadily down the bed with each harvest. The result was a stepped appearance, as illustrated in the picture.

Rotational grazers call the resulting growth pattern a "grazing wedge"; at Rock Spring Farm, we called it "the harvest wave" (I've always had a fascination with surfing, and waves sound much more fun than wedges). Sometimes the wave got ahead of us - the chard leaves would grow over-mature and develop spots, or the oregano would show signs of flowering - and we would cut back the over-mature portion of the bed to manage crop quality and productivity.

Surfing the harvest wave allowed us to minimize harvest labor by reducing the number of steps taken because it encouraged even regrowth and discouraged workers from hunting-and-pecking their way through the field. It also maximized yields by helping us identify when a section of the bed needed maintenance to stay green, healthy, and growing.

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