RATING CLIMATE IN SOUTHWESTERN ONTARIO FOR HORTICULTURAL CROPS

Abstract

A climatic rating scheme was developed for qualitative assessment of land areas in southwestern Ontario for all commercial edible horticultural crops grown in the region. The general approach was to place the crops into three main groups — frost susceptible, frost tolerant, and winter temperature susceptible perennials. A four-point rating system was used to place areas into "very good", "good", "fair," or "poor" categories based on restrictions produced by the critical climatic factors appropriate for each group of crops. The Corn Heat Unit (CHU) map was used as the primary criterion to subdivide the area for the four-point rating. Secondary climatic features appropriate for each crop group were used to further subdivide the crops into subgroups. The climatic features used for the secondary subdivision were spring and fall frost dates, spring and summer maximum temperatures, and winter minimum temperatures. This scheme is the first step in developing a system that can be used to rate areas for their ability to produce edible commercial horticultural crops in this region of Ontario. It should prove useful when combined with soil ratings for these crops.Key words: Vegetable, fruit crop, growing season, winter/spring conditions, land rating