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6 > Image 6 of Kentucky farm and home science, vol. 5 No. 2 spring 1959

Part of Kentucky Agricultural Experiment Station

Efficient use of solar and ground heat enables raising of crop in plastic greenhouse when 6 O *" ()lltSl(l tIllI)12,ltlll`S RPC (lOWI1 to 5 F. Lettuce Grown - No Heat Cost By FRANK li. BORRIES. JR. Vegetables need heat~natural or artificialto grow air space between the two sheets which acted as a heat . bttt Kentucky ,\gricultural Experiment Station horti- cover. (See drawing on opposite page.) _ cttltttrists had surprisingly good results: this year with The whole greenhouse was about 5 feet high. a plastic field greenhouse that got a crop of` lettuce though limmert now recommends a height of 5% to simply by trapping solar and ground heat and con- (5% feet. The roof covering consisted of a dottble serving it. layer of plastic, one fyi-lllll thick inside the frame and li. Nl. limmert, who conducted the trial, found that another 2 mils thick outside. ll is rafter spacing origi- once, when the temperature outside the house was nally was f feet apart; however. this retptires a heavier { onli Fi de trees l`., the tetn >eratttre under an inner >lastic, the fmil thick toe. Two-foot raf`terin can ) D floor covering of plastic was 38 degrees l`., or 35 de- use the 2-mil thick plastic, Emmert says. trees hi ther. He used no artificial heat at all. Instead, he utilized fw The plastic ground cover inside the greenhouse con- sunny days (for solar heat) for the initial warming: sisted of two sheets of 2%-mil thick plastic stretched compacted the soil by watering, which allowed trans- fer of` heat much better than loose soil; and took ad- _ . - . -~= ,,, .,.. , .._ I _,_.... . .._, _ __,_,, vanta e of >rottnd heat arisin from de >ths of a foot . awc - .r... 1 -.-. V -.... . V to rvzr V.V~V Ii. V ,-..t..,- .V./ . V. g h c ` . iV; v t tI"/- lt [til; 'f'VV`4:l i'. EMI,. lV?>r*- LA J f . I I,I I ., I , . I I A. . , , I I , . I ~r__ I _.:_ ,_:=__= ; up ant c t oosc, ttc gtount 1(att stayet in Llc ` = . w. " '/,. . ' -- ;.V1XEJ.T.5;.`: lt/V si5*~` y~ ( jgj ..- 1 _-= gxricgg -,_ ground. \\hen the soil was compacted bv watering, ; I f/pt t ~ . . if _: _,,_ ' _ _ _ ._ _ :,-; the heat filtered through and heated the air nnme- . V. Y V I- ;=-- - - - , V ~_, . ._-_ dtatelv above. Loose soils keep the ground heat from ` I [ r #r,J\.;e ``f " _ ` `hse ``` ```` " . escaping. l`or cxznnpfe, in the winter observers have Q ` IT noted that a plowed field will keep its snow cover c V ~ V" - ~ 6 N M. v VV longer than a compacted field for the same reasons, . _._i , ( I- cw Z I i \ ?- `` . I Qt ...,`.: ? it ` { il ? T ... I `r~. ` `i`;ff V . to ~ ~ A ."s. ` . ` V ~ .Z"-Y*Y cr t `=i T V t `Qs `*\ `ll`i`i; \ sis = est. _ V I ~ -=- I \ == gi. s as . . . . x _ .. . its ? ;~ ~.` = ` . ` `V `xf ` x ?$ Y ""~` . ew . Q 2*; s . V, l' * i*#%:Q?;;- V.,_ _ +,:3 _ __ =? * ` js ` .-X; Ml" its *5 sl; ki;. lf X V \ `\ , Ilorticulttirtst limtnert inspecting evidence of possible snow E; * ` _ it R`? c \ damage to plastic field greenhouse similar to one in which _ V . iii lettuce was produced without use of trtificitl heat T ~ iiil * " ` T ` hg`? r -.4 \" lr l _ _ _ _ 4 ~ ,...: -V~ - > 2 on a ltght wire frame about IS inches above the { _ ` . i_`* { e. ground. f`he cover could be lifted for inspecting the i . , ~i il. ` " ~* ii f A I I I I _ _ _ _ __' . __,__Me I! vaglll &n {M 4%,, v__V I .V, ,2;; V crop oi liatxesting. .\n aisle was left down the middle _ , , . ~.-`=,., ` "_j,;-#_ Q ol the house for access. lhe top sheet of the ground _ _ _ _ __ _ IV _ _ _ _ . . Lettuce growing in a plastic greenhouse without artthcial `