Date of Award

12-2016

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Division of Agriculture (SAFES)

Committee Member

Geoff Zehnder, Committee Chair

Committee Member

William Bridges

Committee Member

Dara Park

Committee Member

Caye Drapcho

Abstract

Combining bottom heating of soil with inexpensive fabric row covers improves yields and prevents cold damage with lettuce and arugula. Two experiments were conducted to determining an ideal heating tube placement and row cover thickness to allow growers to optimize heating systems. Temperature sensors in the first experiment were 30 cm from heating tubes with and without medium thickness (28 g m-2) row covers. A second experiment compared temperatures under medium and thick (62 g m-2) row covers when sensors were placed directly above the heating tubes. Hydronic heat alone increased average minimum nighttime temperature 0.4 C 30 cm from the hydronic tubes. When combined with row covers, average minimum temperatures were 1.1 C warmer 30 cm from hydronic tubes than row covers alone. With lettuce plants grown 15 cm from the heating tubes, plant weight increased 17% more than no heat. Lettuce grown under row covers weighed 70% more than plants without row covers. When row covers and hydronic heat were combined, lettuce 15 cm from tubing weighed 88% more than from the control. Temperature sensors placed 10 cm directly above hydronic tubes under row covers averaged nighttime minimums 3.3 C more than covers alone. Planting arugula directly under hydronic heating tubes increased weight 33% under medium row covers and 60% under thick row covers compared to row covers alone. However, arugula weighed 10% more under medium row covers when compared to thick row covers.

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