In general, tomatoes are set in field or garden as soon as danger of frost is reasonably past. Suppose May 1st is average date of last killing frost. Growers would make general plantings from May 18th to 25th though, in rare instances, frost might occur as late as May 28th or 30th. The last week of May is planting time over a vast area of the North. Venturesome souls will set home garden plants as early as May 10th, standing ready to replant if necessary. There is little gain in rushing the season too much, however, for the tomato is not only sensitive to frost but it does not thrive under what people call "raw, mean, chilly weather." Such conditions may also be responsible for misshapen fruits. A grower for local market not infrequently risks a share of his plants before safe setting time in the hope that warm weather may give the crop a good start toward early ripe fruit to sell at high prices. Delayed planting and use of plants that do not start quickly into vigorous growth is the cause of heavy losses in the north, especially among cannery growers. Better quality and heavier yields are attained if the bulk of the crop matures before cool weather in the fall. In the south, it is necessary to get good plant development and a full set of fruit before hot weather which often destroys the blossoms. Plant Protectors Many forms of plant protectors are on the market--of paper and of other materials. These act as little greenhouses for the individual plant, protecting against frost and promoting growth. Plants may be set out-of-doors a couple of weeks earlier by their use. The most common forms are of translucent paper reinforced by pasted strips of paper or by wire. The trick is to devise one that is cheap, that will admit maximum light and that will withstand the weather. For tomatoes, they need to be tall, which makes the problem of wind resistance more serious. For emergencies, opaque cover, baskets upside down or even newspaper may be used. Many a field has been saved by burying the plants when frost threatened, carefully uncovering when danger is past. Spacing Untrained tomatoes are set at distances from 3-1/2 feet each way to 7 × 7 feet or even more. The extreme width is found on rich irrigated lands in California where plants make tremendous growth. The closer spacings are found on lighter soils where humus, plant food, and moisture are not too abundant. The variety should also be considered. Sixteen square feet per plant is about average. Check row planting is common, though it is not feasible where transplanters are used. Wider spacing between the rows than between plants is desirable as it permits later cultivation one way and leaves a better passage for pickers with less damage to plants and fruits. Thus, 3-1/2 × 4-1/2 feet might be preferred to 4 × 4 feet.