Seed may be sowed a week or two after "average date of last killing frost" which may be learned from county agent or weather bureau. Further south planting times are gauged by the time tomatoes are to be set and by experience as to safe or reasonably safe sowing dates. Rows are usually a foot apart, more or less. Good plants call for sowing thinly, 6 to 12 seeds per foot, but several seeds per inch are not unusual. One may expect a million plants per acre with close planting or 40,000 plants per pound of seed. Southern Plants Many millions of tomato plants are grown in open fields in the south to be sent to home gardeners in small parcels on seedsmen's orders, to be sold to commercial growers or to be delivered on contract to canners. A suitable climate and soil, good seed, freedom from disease and insects and good handling and packing are all required for satisfactory results. In far too many cases, these requirements have been sadly neglected and a good deal of distrust has been engendered. Here, as in buying seed, one must discriminate among good and poor growers. Canners who order in millions can send men south to investigate and supervise with good results. Georgia now has a certification service for plants that helps greatly to build up and maintain high standards. Growing Early Plants in the North Varied programs of plant growing are in vogue in the temperate and cooler regions. A simple cold frame with or without transplanting may be employed. Seedlings may be started in hotbed or greenhouse and then transplanted to cold frames to finish the job. Some sow seed early, transplant once in the greenhouse at 1-1/2 or 2 inches each way and then again to cold frame with wide spacing say, 4 × 4 inches or using pots or dirt bands. For this method, as much as twelve weeks may be allowed but if space permits, excellent results may be achieved in seven or eight weeks transplanting but once to pots or to 4 × 4 inches in flat or bed. [Illustration: FIGURE 11.--A good small greenhouse for plant growing.] The Place to Grow Plants For northern climates, greenhouses are practically required. Canneries or other large growers, have wide houses similar to those used for winter maturing crops. A market gardener may have a little house of 10´ × 20´ to 20´ × 60´ or larger as needed. If one does not object to some inconvenience and discomfort, a hotbed may be used--heated with hot water or electricity, or as in years past, with fermenting manure. Cold frames may be covered with glass sash as in the case of hotbeds, or cloth may be used. There are also materials consisting of wire cloth filled with cellulose film. Special mats of straw or of quilted burlap may be used for extra cover and large growers often employ coarse manure, straw or marsh hay. Many a tomato gets its start in life in a small flat in a kitchen window--perhaps, in a cigar box. Such seedlings may then be carried forward in hot bed or cold frame.