BuildingaMoveableHighTunnelfromaKit

Inthefallof2014,studentsandstaffconstructedthree30’by48’moveablehightunnelsontheSERPplotsattheMSUHorticultureFarm.Thehightunnelsfeatureasinglelayercoveringofgreenhousepolyethyleneplasticfilm,rollupsidewallsandwovenplastic‘fabric’endwallswithzipperclosures.

Formoreinformationcontact:DavidBaumbauer(406)994-2231orhortfarm@montana.edu.

Picture1.Beforepurchasingahightunnelkititisagoodideatoaskthemanufacturerforacopyoftheassemblyinstructions.Thequalityoftheinstructionsgivessomeinsightintotheeaseofassembly.Whenyourhightunnelkitarrives,takethetimetotakeaninventory.Therearemanysmallpiecesandafewspecializedonesthatmaybedifficulttosourcelocallyifyourunshortduringconstruction.

Picture2.Locateyourtunnelonlevelgroundwithhighqualitysoil.Avoidareasthatareshaded,especiallyinthespringandfall,sincethesunisatalowangle.Layoutthefootprintandcornersofthetunnel.Usethe3-4-5ruletoget90⁰rightangles.

Picture3.Assemblehoopsonaflatsurfacewhichwillaidinhavingthehoopandtrussassembliessquare.

Picture4.Levelandcompactthesoilunderthepipetrack.Rolloutlandscapefabricandplacethepipetrackontopofthefabric.Thefabricwillkeeptheweedsdownandhelpkeepthecastersoutofthemud.

Picture5.Settingthefirsttwoarchesrequirestemporarybracingtoholdthearchesinplacewhilefasteningthepurlins.Unlikeatraditionaltunnelthatutilizesgroundposts,moveabletunnelsarenotattachedtotheground.Withthefirsttunnelweusedropeandratchetstrapstoholdthearchesinplace,butitproveddifficulttouse.Subsequenttunnelsusedfixedbracingtoholdthearches.

Picture6.Notethetwowoodenjigsthatwereconstructedtoaidinspacingthearchesonfourfootcenters.Webuiltthreespacingjigsandtheywereveryhelpfulintheconstructionprocess.

Picture7.Fourarchesareinplace.

Picture8.Thearchesarecompleteandtheendwallframingisnext.

Picture9.Thehipboard(wooden2X6)isattachedtotheframeandispositionedatthetopoftherollupsidewall.Tunnelswithoutrollupsidewallshavethisboardlocatedatthebaseofthehoops.Thebaseofthepolylockisattachedtothehipboard.Fabricendwallsareattachedpriortoinstallingtheplasticfilm.Thecrewispreparingtopullthegreenhouseplasticfilmoverthehoops.Aminimumcrewoffourisrequired,threetopullthestringsattachedtotheedgeoftheplasticfilmandthefourthtokeepthefilmflowingoverthehoops.Calmandcoolconditionsarerequiredforpullinggreenhouseplasticfilm.

Picture10.Theremainingcrewmembersliftthefilmsothatitdoesn’tsnagontheframeasitisbeingpulled.

Picture11.Plasticfilmisattachedtooneendwallthenpulledjustenoughtogetthewrinklesoutofthefilm.Polylockholdsthefilmtothegreenhousewithoutpenetratingthefilm.Thefilmisattachedtothehipboardswithpolylockandthebottomedgeofthefilmisattachedtotherollupsidewallsystem.

Picture12.Thecompletedmoveablehightunnel.Castersatthebaseofthehoopsarevisibleasarethestakesandstrapsthatattempttoholdthetunnelinplace.Endwallsarefullyopenandsecuredwithstraps.

Picture13.Oatcovercropisterminatedandthesoilwithinthetunnelhasbeenbroadforkedandrototilled.

Picture14.Twoinchesofcompostwereappliedtotheplots.

Picture15.Thecompostwasincorporatedwitharototiller.

Picture16.Thefirstcropwasplantedinmid-March2015.