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Nova Scotia has over 100 commercial greenhouses covering an area of 186,245 square meters. Heating costs have become the largest energy expenditure in greenhouses mainly due to increasing fuel prices and the use of imported fuel oils. Increasing fuel prices combined with a growing desire to stabilize energy supply has led to a renewed interest in alternative fuel options for greenhouse heating. Agricultural or herbaceous biomass has the potential to become a sustainable and cost effective heating option for the greenhouse industry. Although high inorganic content create challenges during the combustion of herbaceous biomass, these crops create an opportunity if sufficient land mass is available for greenhouse growers to meet their own fuel needs. This research will review energy use and operational practices in the greenhouse industry to identify energy saving opportunities. This study will further investigate biomass feedstocks, processing and combustion technologies suitable for heating greenhouse industry in Nova Scotia.

Protective cultivation is widely used nowadays in order to increase crop yield by creating the optimum conditions such as temperature, humidity and CO2 content, irrespective of outside conditions. Since plant production doubles for every 10 degrees increase in temperature to a certain limit, this makes temperature a very important factor for optimum plant growth. In order to keep the greenhouse temperature constant during changes in outside conditions, heating and often cooling are required. Heating of a greenhouse can be done using different systems and design procedures. The applicability of different types of greenhouses is studied at the field local conditions, &Ccedil / avundur-&Ccedil / ankiri, Turkey. Required heating load was calculated that is due to infiltration and conduction through the greenhouse cover at a single design point, which is the minimum outside temperature. Two types of heating systems, soil heating system and bare tube system, were considered. Analysis of results showed that, &Ccedil / avundur geothermal field with 54 &deg / C fluid temperature is suitable for greenhouse heating. Although the existing well &Ccedil / -1 is capable of producing 47 l/s, the flow rate of geothermal fluid for greenhouse heating was limited by 35 l/s due to existing thermal facilities in the area. Among different glazing materials, plastic film covered greenhouses with double poly was found to be the most suitable in terms of heat load calculations. The maximum number of greenhouses (the area of each green house is 216 m2) that can be heated by &Ccedil / avundur Geothermal field was found to be 138 by considering soil heating with double poly glazing material. Annual heat load factor of geothermal energy for greenhouse heating in &Ccedil / avundur area was found to be as high as 96% depending on indoor design temperature and base load.

<p>As the world population continues to grow, it will be challenging to manage resources, reduce environmental pollution and maintain growing demand for food production. Controlled environment agriculture (CEA) is a novel solution to reduce freshwater use in agriculture, minimize environmental pollution from agriculture sector, and meet the growing food demand. CEA allows for the year-round cultivation in inhospitable climatic conditions. Hydroponics is a common method of growing crops in CEA, where plants grow in a solution enriched with nutrients and oxygen. The technique significantly reduces water use and fertilizer run-off during production. In the United States, lettuce is one of the most important crops grown using hydroponics.</p> <p> Hydroponic production uses several methods to grow lettuce including nutrient film technique (NFT) and constant flood table (CFT). Moreover, several cultivars of lettuce are grown in the Midwest. There is a lack of knowledge on whether optimal fertilizer concentrations change depending on the cultivar or hydroponic production system. Little information is known about the suitability of a cultivar to a specific method of hydroponic production. For year-round lettuce production in hydroponics, supplemental lighting (SL) and heating are required in the Midwestern regions of the U.S. The energy requirements for SL and heating can be too costly in winter for some growers to produce crop year-round. In addition to light quantity, spectral composition of light can impact growth. Heating the root zone to produce a micro-climate may be more efficient than heating the entire greenhouse and possibly reduce overall heating costs. However, information on spectral composition of light and the efficacy of root zone heating is unclear, at best. Certain cultivars that can tolerate cold stress can be more suitable in the U.S. Midwest during winter. Lettuce cultivar screening for yield under cooler environments is limited. </p> <p> A completely customizable hydroponic production system that can aid in conducting research related to above-mentioned issues was built as a part of my Master of Science program. Using this system, 24 popular cultivars from four lettuce groups were evaluated for productivity during summer/fall under different concentrations of fertilizer solution, and in two production methods including NFT and CFT during spring. In addition, yield of all 24 cultivars were evaluated under 10, 15.5 and 21.1 °C in a growth chamber. The eight best performing cultivars from the summer/fall trial were evaluated during the winter in a greenhouse with the addition of SL and root zone heating with minimal ambient air heating. </p> <p> Results indicated that the lowest level of electrical conductivity (EC) of the fertilizer solution used (1.3 dS·m^-1) resulted in highest yield, regardless of cultivar or method of production. Among the 24 cultivars; Red Sails (Leaf), Salvius (Romaine), Cedar (Oakleaf), and Adriana (Butterhead) had the highest yields among each group during summer. Growth chamber study indicated that Dragoon, Adriana, New Fire Red and Red Sails cultivars had higher yields than other cultivars under cooler (10 and 15.5 °C) air temperature conditions. In the winter study, lettuce cultivars did not reach harvestable size even after 40 days of growth without SL and root zone heating. Supplemental light composition significantly affected lettuce growth with higher yield under Purple (with higher proportion of red) than White LED lighting. Commercially acceptable lettuce could be produced using root zone heating. In general, plants grown under CFT yielded higher than those grown under NFT in the winter trial. Among the cultivars, Salvius, Black Seeded Simpson, Cedar, and Red Sails performed better under SL and root zone heating during winter.</p>