turkey wire. Wider end pieces 

 (shoes) allow them to be stacked. 

 Up to 14 (two stacks of seven) oi 

 these stackable modules can be 

 moved at one time on a hydraulic 

 pallet truck. Another method of 

 moving them is stacking them 

 three-high on a "go-fer-style cart" 

 that can be rolled down a 2 1/2' 

 wide walkway. Because all the 

 houses are connected, this mobility 

 can be used to advantage: modules 

 can, for example, be brought from 

 one house, filled with pots, and 

 then returned to another area. 



The stringers (undertrames) on 

 which the modules are placed vary 

 in size. Those in a 25' wide house 

 are approximately 8' long — one set 

 on the left; one on the right, ot a 

 nine-foot wide service aisle. In 

 times of heavy production, pipe 

 telescopes from each stringer to 

 accommodate two more modules — 

 24 square feet of additional growing 

 space, bringing the width of the 

 walkway down to around 18 inches. 

 Plants on these cantilevered 

 modules are sold first or moved as 

 other bench space opens up, 

 recreating the spacious walkway. 



Plants are moved from the back of a 

 bench toward the front, then from 

 far benches, and then from far 

 houses. The material is always 

 being pulled toward the central 

 retail area (approximately 36x174) 

 which spans the entire gable end oi 

 the Nexus complex. Empty houses 

 are closed off to conserve heat. 



The Murrays are using "DIP" to 

 control poinsettia and lily height. 

 Basically, this technique of 

 temperature control is based on the 

 fact that cooler days and warmer 

 nights will produce a shorter plant 

 than the more traditional warmer 

 days and cooler nights. (DIP was 

 discussed by Nancy Adams in the 

 June/July Plantsman). Dave says 

 the difference in height is 

 remarkable. He went from growing 

 three-foot lilies to growing 16-20" 

 ones without any additional use of 

 growth regulators. This year's 

 poinsettia crop (on which a 

 regulator was used once) is full and 

 compact. 



A Wadsworth MicroStep, a 

 computerized system that can 

 control up to eight separate heating 



zones, was recently installed. 

 Multiple menus allow you to 

 customize your heating and cooling 

 loads to the exact requirements of 

 whatever crop you're growing. Four 

 quonsets and four sections of the 

 Nexus range are currently using this 

 system. Dave feels the cost "is 

 worth every cent." 



The heating system is a dual 

 system. The main — hot water — 

 system is housed in the main 

 building, the former hatchery. 

 There are three separate boilers — 

 the main boiler bums wood chips; 

 two secondary boilers bum oil. 

 When the water temperature is not 

 up to what it should be, acquastatic 

 demand turns on the secondary 

 boilers. The water temperature is 

 boosted as it passes through them. 



When the radiational output ot the 

 hot water system can't keep up or 

 fails, then the hot air system kicks 

 in. This is fired with natural gas 

 modine heaters located in the 

 greenhouses and is Microstep- 

 controUed. A four-degree heat loss 

 will trigger this system. 



Dave admits to being "something ot 

 a boiler scrounge." The main 

 boiler — which bums wood chips — 

 IS a cast iron H. B. Smith that came 

 out of a bank in Concord. Before 

 housing the bank, the building had 

 housed a supermarket. The boiler 

 had been there tor 32 years, but 

 because it was oversized for the 

 space and because oi the heat 

 generated by the market's lighting 

 and compressors running the 

 cooling units, it was underused and 

 in great shape. Dave had it re- 



nippled and it was like new. 



Of the two oil boilers, one was 

 picked up second hand by Jesse 

 sometime in the lace sixties; the 

 other — a '67 cast-iron American 

 Standard — Dave picked up about a 

 year and a half ago from a school in 

 Concord for about $400. (Just 

 before the new year, Dave acquired 

 a 3,000,000 Btu cast iron boiler- 

 three times the size of Murray 

 Parms' present main boiler — from 

 another Concord school. Now he's 

 figuring out what to do with it.) 



The chip-burning system was put in 

 eight years ago when the first bays 

 of the Nexus house were built. 

 Today, a typical winter week's 

 supply of fuel is thirty tons (a 

 trailer-load) of hardwood chips. 

 The Murrays own five 40' 

 semitrailers and hire a trucker to do 

 the hauling. ("Hiere's no problem 

 getting the stuff and it's definitely 

 less expensive than oil.") But 

 sometimes the mills are producing 

 softwood chips (which hold more 

 moisture and don't bum as well), so 

 they try to keep a month's supply of 

 the hardwood chips on hand. 



The trailers are unloaded with a 

 bucket loader into a hopper-like 

 stoker. During heating season, the 

 stoker never shuts down, the boiler 

 being in either a high-fire or low- 

 fire (standby) mode. In the 

 high-tire mode, the boiler calls for 

 ten seconds of chips every four 

 minutes; the low-fire mode calls for 

 three. An auger automatically 

 pushes the chips outward until they 

 cascade into a secondary auger (the 

 space between the augers creates a 



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February/March 1992 19 



