The 2012 ASHS Annual Conference

In 2011 and 2012, three interviews or visits were conducted with 31 Maine high tunnel owners to identify common practices, benefits, and challenges.  Basic data was collected on 52 tunnels and detailed data was collected on 31 tunnels.  Soil samples were collected in mid-summer and analyzed for nutrients using standard soil test methods, saturated media extract, and other measures of soil quality. Twenty-four tunnels were a year or less old at the start of the project.  Eight farms were certified organic, 23 were not.  Forty-five houses were gothic-style, reflecting the design needed for a 4-season house in Maine’s winter.  Seven houses were Quonset-style and   some were managed as 3-season structures.  Most tunnels were oriented E–W (59%);  37% were oriented N-S;  4% were NE–SW (n = 51).  Tunnels were most often 17’ (19%) or 30’ (29%) wide and 48’ (21%) or 96’ (33%) long (n = 52).  At construction time, 11 farmers made specific efforts to improve drainage.  An additional 5 reported drainage problems with a new tunnel.  The primary crop grown was tomatoes (81%), followed by greens (56%), cucumbers (47%), and peppers (44%) (n = 31). Compost and/or manure was used prior to planting in 94% of the tunnels;  32% received additional nutrients as sidedress or fertigation (n = 31). Elevated organic matter (>8%) and salt levels (> 2mmohs/com) were found in 54% and 30% of tunnels respectively.  In addition, soil test results showed pH below the recommended minimum of 6.5 in 70% of tunnels (n = 37). Primary irrigation methods were drip (61%), overhead (17%), or hand watering (12%) (n = 41).  Twenty-six percent of tunnels had no mulch within crop rows and 29% had no mulch between crop rows (n = 42). Farmers reported that growing in high tunnels allowed early and late crop production and higher crop quality.  This led to some farmers relaxing their early-season planting schedules or shifting production of certain crops (such as tomatoes) entirely to high tunnels.  Differences in labor requirements and pest pressure were also reported.