Greenhouse Page

Some History

In 1987, when I was recruited for my current position, the greenhouse facilities were limited to a 12' x 17' lean-to glasshouse adjacent to a laboratory building. This mini-house was (unbelievably) situated in the shadow of the building for most of each day. As part of my "recruitment package," I was promised suitable research greenhouse space which I defined as a 40' x 60' greenhouse in full sun.

The "Temporary" Solution

In January 1994 new greenhouses were finally finished so that they could be occupied. Lacking the luxury of a capital project funded by the State, "temporary" facilities were built. These consisted of two 20' x 44' hoop houses (about 1800 sq ft) with a nine-foot peak and polyethylene glazing. The end walls were wood and included one entrance. The substrate was pea gravel with concrete pavers for aisles. The benches were Structural Plastics 2'x8' modular units with PVC pipe for legs. The greenhouses were located approximately three blocks away from our laboratory building on a bluff within a parking lot. Due to vandalism of the polyethylene, a cyclone fence was erected completely surrounding the two units. The houses were wheelchair accessible, included wheel-chair-accessible work stations, and the parking lot had an adjacent parking space for wheelchair unloading. The buildings that were torn down to make room for the greenhouses were "temporary" classrooms (portables) that had been in place for more than 25 years. These greenhouses were similarly "temporary" for 15 years.

Temperature Regulation

The temporary greenhouses were heated with natural gas forced-air, and cooled with electrically operated vents and exhaust propeller fan. Both units had air circulation fans and blowers to keep the two layers of polyethylene separated. Summer cooling was enhanced by 55% shade cloth thrown over each house and lashed in place. One house was covered year-round and thermally regulated to make a "tropical rain forest" environment (warm/humid). The other was shaded May to October for cooling and was kept cooler and drier than the other unit. The units were equipped with Sensaphone security equipment to phone my office, home, and the physical plant staff if temperatures exceeded set limits. In the range of 15 years, this system never cooked or froze any plants. It was very dependable.

Watering System

The watering system was run by a zoned timer to water both houses twice each day. The zones varied in how much water was delivered. The water was injected with fertilizer to keep approximately 100 ppm nitrogen in the lines. The fertilizer used was typically Peters soluble 20-20-20 (or equivalent) with some micronutrients. The irrigation system used bench runs of 0.5 inch polypropylene pipe from which "octopus" fittings connected to "spaghetti" tubing to each pot. At the end of the spaghetti tubing was an emitter stake that provided drip irrigation to its pot. Larger plants had more than one emitter, or the emitter could be adjusted slightly to increase the watering at each interval. The Netafim emitters had a tendency to clog over time and, if one of the eight tubes became disconnected from the octopus fitting or an emitter was pulled from its spaghetti tube, the other seven pots were not watered. Argh! This system needed some improvement. The Dosatron fertilizer injector in the shaded unit lasted all 15 years, but the one in the sunny greenhouse had to be replaced or overhauled twice. I guess that the plastic housing became too brittle in the greater UV exposure causing the cracks.

Potting Media

The potting medium was typically Fafard #2 or Pro-Mix BX. This was somtimes amended with vermiculite or, more typically, perlite depending on the species being potted. Obviously plants needing better drainage and more soil oxygen got the perlite, those needing wetter soil got the vermiculite addendum. Plants were grown in a variety of pots, but I tried to standardize on Kord 4.5" geranium pots for "typical" small plants. Larger species or longer-term plants were often put into 10" bulb pans to avoid tipping over. Part of our collections included large specimens in 18-quart totes, and even a 110 gallon horse trough (for Amorphophallus), and many course plants were grown in standard plastic flats. Aquatic plants were grown in Rubbermaid polypropylene storage bins, and a water-filled "pallet topper" (4' x 4') was maintained for rooting cuttings, and keeping a thriving culture of Daphnia alive.

Pesticide Use

Pesticide use was kept to a minimum as we were basically on soil. Plants with severe infestations of mealy bug and white fly were discarded, and in rare cases of irreplaceable plants were treated with Orthene. Sunspray oil left our plants too slimy for common use. Safer soap was used for minor infestations. We later had considerable success with biological controls for mealy bugs (Cryptolaemus) and for white fly (Encarsia).


These greenhouses were primarily for teaching and secondarily for research and outreach.
The teaching collection included an increasingly wide range of plants from algae, to bryophytes, ferns, gymnosperms, and angiosperms. Classroom projects for Plants and Human Affairs, Biology of Plants, and Plant Physiology were present each semester. Plants were raised as basking substrates for reptiles in the Animal Behavior class. Daphnia was cultured for feeding salamander larvae. Typically there were two to four independent study projects underway in the greenhouse.

Greenhouse tours were popular with the local middle school (one block away) and nearby day care facilities. Science fair projects in elementary school and middle school were carried out in the facilities each year. The eighth grade (middle school) science classes had a spring planting unit and raised plants for a huge plant sale. The proceeds were invested in biotechnology stocks and the proceeds helped fund the science program in the school. Biology students from Windham High School's Experimenta program had projects in the greenhouses; one team was a winner at the State Science fair.

The greenhouse also produced plants for the Windham Community Organic Garden (sponsored by the Windham Area Interfaith Ministry and the Puerto Rican Outreach Program); 100 dozen plants were donated in 1994 and 50 dozen were donated in 1995.

The greenhouse was also the plant "hospital" for the campus and plants needing some light, water, and fertilizer were routinely brought in for R&R. Plants were brought "back to life" for the President's office and for "major" financial donors.


This facility was maintained personally by Dr. Koning with fewer than 5 hours per year of work-study student assistance. For a year or so some volunteers from the community assisted and had a good impact on the appearance and "health" of the greenhouse. After 2000 the dean of Arts and Sciences started providing a greenhouse student assistant that provided a maximum of 15 hours each week of help. In some semesters the student did the full time, but in most semesters the students ran into academic workload issues and provided fewer than 2 hours per week. Obviously this greenhouse thrived on neglect. Thank goodness for the automated watering/fertilizing system!

The Research Greenhouse

After 2000 the plans were underway to construct a new Science Building, and the campus president encouraged us to "dream big" and so an ambitious state-of-the-art greenhouse facility was programmed, and designed. But the president refused to locate it on the roof and could not be dissuaded from having the greenhouse at ground level. But the Science Building project was not funded by the State of Connecticut. During a two-year unfunded interval, the programs and designs were "value engineered." The air conditioning capacity of the building was reduced so that it was insufficient to supply the greenhouse with active cooling. The construction team was allowed to remove the only remaining active cooling (exhaust fans) as "not needed." Which, once the air conditioning was removed, obviously was untrue. Expensive change orders were issued to restore the exhaust fans, to reinstall the insulated glazing, to motorize the shading, and to install a fogging system to at least give some respite from summer ambient heat plus solar gain. Construction was mostly finished in August 2008 and the move from the "temporary" greenhouses was begun in Fall 2008. But the building was not issued a permanent certificate of occupancy until (still waiting as of January 2010).

A special commendation was presented to undergraduate, Brenton LaTour, in spring 2009. Brenton was the greenhouse student assistant from Fall 2008 through Fall 2009. He was responsible for axenically propagating all the plants in the old hoop houses and bringing them into the new greenhouses. This was no small project given the size and range of the plant collection of the university. But it was critical given the extent of the pest infestation of the old greenhouses. While a very few species still remain in question in terms of propagation in December 2009, virtually all were successfully cloned. The new facilities remain comparatively pest-free. We are especially grateful for the elimination of Oxalis, garden slugs, mealy bugs, and two-spotted spider mites. Thank you Brenton LaTour for amazing service!

Features of the "Permanent Greenhouse"


The greenhouse consists of four bays, but with no active cooling and needing to control heat with shading, our ability to make meaningful differences between these bays is extremely limited in early fall and late spring. But each bay does have individual computer controls that allow at least some variation among the bays during the winter months. The venting systems failed, the heat exchangers failed, and plants were frozen twice during its first winter (the cheap polyethylene greenhouses did not freeze plants even once in 15 years).


The best feature of the greenhouses is clearly the flooring. By having a concrete floor we can keep the greenhouse cleaner. By having drainage to sewage handling facilities, we can use pesticides to control outbreaks of pests. While the vents are screened, the vent operating jacks provide huge openings to the outside air and this has allowed pests to come in during the fall and spring. But the lack of rats, mice, and chipmunks has been very much appreciated.


The floors slope to floor drains as one might expect, so to have level benches you would expect them to be very flexible and adjustable in design. What we got from the designer were four-part benches with metal legs that have to be drilled through every time a bench needs to be moved. Because they are "rolling top" benches, they need to be moved by about three people. The benches look OK when adjusted, but move one a few inches and they look all crooked and crazy. Obviously ebb and flow irrigation was out of the question! I would NEVER recommend these benches to anyone.

Watering System

There was no automated watering system until spring 2009, so Dr. Koning was making once or twice daily visits to the greenhouse to water (of course including weekends and snow days and vacation days!) until April. But the Dean of Arts and Sciences provided funding for some watering systems to alleviate this burden. There will be no automated fertilization system other than a backpack sprayer used to distribute fertilizer manually on a twice-monthly basis. This decision was based upon the poor service record of the injectors previously used.


Lighting in the new greenhouses is of course a major issue. Between the programming and design phases and the funding and construction phases for the Science building, fast-tracked projects to build new dormitories on the south side of the planned Science Building footprint were funded and the 7-story dorms were erected and occupied before the five-story Science construction began. The Science footprint was moved westward. A sun study done during the design phase of Science showed NO sun obstructions for the greenhouse. But the new dorms and the move toward the older High Rise dormitory provided sun obstructions in the greenhouse that were not appreciated until the construction was underway. The unilateral decision to keep the greenhouse on the ground ensured that the greenhouses do not get a sunrise event (over the new dorms) until about 10 AM and the sunset event is about 1 PM (behind the older dorm) from fall to early spring. During the flurry of change orders, negotiations to increase the artificial lighting capacity apparently failed to increase what was left after the "value engineering." There were many misunderstandings in the execution of this facility. So the limited lighting is on most of every day adding to the amazing energy costs of this new building. Would that our president had heeded my arguments for the greenhouse on the roof.

In defense of the president, I think his dogged determination to stay on the ground was motivated by a visit to a university where a roof greenhouse was badly engineered or executed and leaked throughout the building. Sadly he was unconvinced by the many examples of successful greenhouses on rooftops at many univerisites in the USA...including one just a few miles away. But decisions do have consequences and our energy costs to light the greenhouse at the bottom of a concrete and brick canyon are those consequences.

A rooftop design...but at grade level?!

Interestingly, the new greenhouse, while "at grade," has utility rooms in the basement below the the design required for a roof greenhouse is precisely what we have "at grade" to avoid leaking into the basement below. There have been no major floor leaks to date! So the President's choice is both ironic and tragic.

New Support Facilities

There are two amazing features of the new greenhouses. One is the adjacent large air-conditioned headhouse for potting up plants, making cuttings, doing scientific tests and observations, etc. The casework is all stainless steel and there is sufficient space to have a class of 24 students in there working on projects! The other amazing feature is a laboratory space to conduct plant tissue culture and other plant physiology projects. The laboratory has laminar flow hood, a -80C freezer, refrigerator, benching and cabinets for research, and a computer that can control the microprocessors in each of the four greenhouse bays. An autoclave was installed in the closest greenhouse space. These two facilities were NOT available in our older spaces and these two features make up, at least in part, for the initial difficulties and the ongoing problems we face in the greenhouse cooling area, etc.

Finishing Up

By spring 2009, we still did not have the motorized shading, nor the exhaust fans installed, and the fogging system ws not functional. Once these were installed and working in summer 2009, further training for Dr. Koning was required to provide for summer uses and to protect our students and guests from excessive heat exposure. By late summer 2009 we were able to stay within a few degrees of ambient temperature (providing it was dry, and 2009 was a cool summer). By our first anniversary in the new greenhouse we achieved the effect of at least being able to maintain safe high temperature. The ability to control temperature from 50 to 90 F, as programmed, designed, and claimed by designers, engineers, and CT DPW, of course was an impossible target after the "value engineering" of the Science Building systems and remains an unfulfilled promise.

Grant Funding

In August 2009 Dr. Koning wrote a grant proposal which was funded by the Stanley Smith Horticultural Trust to install a coldroom space in the basement of the Science Building. This new facility will replace some of the lost capacity of the greenhouses to permit bulb forcing and stratification/vernalization of seeds and biennial plants. Whether the University can meet its matching fund and installation commitments remain to be seen.

Plant Donation

In December 2009 the University was the recipient of a magnificent staghorn fern donated by Gordon Muir of Windham, CT. This specimen has been hung in the third bay of our new greenhouses temporarily, while the floor drains are serviced in January 2010. It will be moved to a more-permanent location in the first bay after this repair project is completed.

Arranging Tours

If you are local to the Willimantic, CT area, a greenhouse tour can be arranged by calling Dr. Ross Koning (860-933-2712). Tour groups are limited to 25 or fewer people and can only be arranged around Dr. Koning's schedule.

I hope to add more to this page (perhaps especially photos!) as I get time and finances to add things...eventually I hope for a guided virtual tour of the greenhouses...and maybe a web-cam to see latest happenings in our new facilities.

This page © Ross E. Koning 1994.

Go to the Plant Physiology Information Homepage.

Send comments and bug reports to Ross Koning at koningre∂gmail⋅com.