"Shrink-Wrapping" Grapes Boosts Production

Shrink-Wrapping Grapes Boosts Production CROPS New Techniques Wrapping grapes in shrink-wrap plastic lets Tom Miller grow grapes where he otherwise couldn’t The plastic envelope extends the season and adds growing degree days on Washington’s cool and windy Olympic Peninsula “In a good year some winemaking varieties may ripen but others will not ” says Miller “Enveloping the vines for 6 weeks in the spring and until after fruit set provides about a 25 percent increase in growing degree days during the season It’s like moving my vineyard 300 miles south for 6 weeks ” Miller has experimented with wrapping his grapes in plastic since 2007 However he feels he finally perfected the process in 2011 He uses rolls of shrink-wrap plastic film that are 30 in wide by 6 000 ft long The film is doubled over and attached to 32-in long 1 by 2 stakes which have been nailed to trellis posts One $120 roll covers both sides of 3 000 ft of trellis The two sides are then pinned together at the top with clothespins The plastic is installed around the first of May and removed around the first of July When shoots reach the trellis midwire the clothespins are removed and the top left open He also tops shoots to encourage healthy fruit clusters Miller devised a simple dispenser for the plastic He fabricated it from scrap lumber plywood rotating casters iron pipe and plastic plumbing caps “I used a standard pallet carrier for a 3-pt hitch and bolted a plywood platform to it ” he says “I attached four caster wheels upside down to the platform around a 1/2-in pipe A circular drum made out of scrap lumber slips over the pipe as does the roll of plastic ” The drum rides on the casters like a Lazy Susan It does triple duty also serving to dispense trellis wire and drip irrigation tubing The pipe is threaded at the end with pvc spacers and a 3/4-in cap Miller reports that a group of three people can wrap the one-acre vineyard in a day Removing the plastic takes about the same time “The plastic isn’t re-useable as the sun decays it and the wind rips it apart ” says Miller “We roll the plastic up into balls that fill two plastic garbage bags ” Contact: FARM SHOW Followup Tom Miller Sequim Wash vrc@olypen com

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