1999 Annual Report for FNC99-286
Lettuce Season Extension Trials
Summary
Vegetable producers often run into problems of season length in raising, harvesting and marketing their products. Producers who show creativity, innovation and problem-solving abilities in their operations reap more benefits from their enterprise.
Objective: To document trial results of different strategies in lettuce season extension.
The producer employed trials to measure overwintering, unheated and hoop greenhouse production, seedling survival, yields, plant survival and annual planting schedules.
The producer organized four 20-by-400-foot test plots that are seasonally climate-adjusted with black weed barriers, glotextill- or plastic-covered hoop tunnels, unheated greenhouses, aluminum and multi-colored shade cloths, misting and various cultivars.
Results: The producer marketed his high quality, organic head lettuce and salad greens to first-class restaurants and several individuals in February through July.
He reported that his overwintering trial failed, which was indicated by high weed infestation and low yield weight. Also, the common practice of harvesting reduced yields throughout the summer was discontinued because it resulted in low yields from bolting, slow re-growth, bitterness and disease susceptibility.
The producer wrote a manual on lettuce production for beginning- through expert-level farmers. It included a detailed production calendar:
January - Salad greens are growing under light-weight row covers in hoop greenhouse.
February - Harvest salad greens in unheated greenhouse around the 15th. Replant where plant population density is low in greenhouse. Plant salad greens and head lettuce under heavy-weight row covers in outside fields.
March - Continue planting salad greens and head lettuce under covers in outside fields, until soil temperatures stabilize above 55 degrees F. Then, plant uncovered.
April - Continue planting head lettuce in outside fields. Harvest salad greens in outside fields. Phase out salad greens in greenhouses to prepare for outside field management.
May - Continue planting head lettuce in outside fields. Plant double the amount of salad greens in outside fields to prepare for July market demand. Continue harvesting salad greens in outside fields. Harvest head lettuce in outside fields.
June - Shade all new salad greens and head lettuce plants in outside fields around June 1st.
July - Harvest salad greens and head lettuces under shade.
August - Plant salad greens and head lettuces under shade.
September - Harvest salad greens in outside fields under shade. Continue planting salad greens in outside field. Take down shade around the 15th.
October - Continue harvesting salad greens in outside fields. Harvest head lettuce in outside fields. Plant salad greens in hoop greenhouse.
November - Install row covers in outside fields of head lettuce and salad greens at the first of the regular heavy frosts. Harvest salad greens in hoop greenhouse.
December - Harvest head lettuce in outside fields. Install light-weight row covers on salad greens in greenhouse.