Heat transfer problems in plastic covered tomato greenhouses with ground beds in Manitoba

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Shaw, Jai-Tsung.
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Most people like big, fresh tomatoes for making sandwiches and salads. The major supply of tomatoes for Manitoba is produced in Ontario, the United States or Mexico. Unfortunately, these tomatoes do not have the flavorful quality of vine-ripened tomatoes. The transportation expenses and the damage done in transit add to the final cost to the consumer. A marketing study found that consumers were willing to pay a higher price of up to twenty cents per pound more for greenhouse tomatoes compared to storage ripened tomatoes. Manitoba greenhouse tomato producers can profitably fill the shortage in the local supply of high quality tomatoes if technical information is available... The scope of this investigation was limited to areas where immediate problems existed. The main problem area was steam sterilization of the ground beds using portable steam generators. The other problem areas were the design of the heating system and the design of the ventilation system. The objectives were: 1. To evaluate steam sterilization of the soil beds and to compare with chemical sterilization. 2. To compare estimated heat losses with that estimated from the measured fuel consumption. 3. To estimate solar heat gains and to evaluate the ventilation system design for removal of excess solar heat.