What is the proper way to plant tomatoes?

Plant tomatoes in the garden after the danger of frost is past.  In central Iowa, it’s usually safe to plant tomatoes around May 10.  Gardeners in southern Iowa can plant one week earlier, while those in northern counties should wait an extra week.  The last practical date for planting tomatoes is approximately June 20. 

Plant tomatoes in full sun.  The planting site should receive at least 6 hours of direct sun each day.  If the plants are in peat pots, tear off the top edge or make sure the top edge is well below the soil surface once planted.  If the top edge of the peat pot is exposed to the air, it will act like a wick and draw water from the soil around the plant.  If the tomatoes are in plastic pots or cell-paks, carefully tap out the plants. 

Set plants into the soil up to their first true leaves.  Pinch off the bottom leaves of tall, lanky transplants and lay them sideways in a trench.  Carefully bend the stem upward so that the upper few inches of stem are above the soil surface.  Roots will develop all along the buried stem. 
 
Spacing of plants depends on the growth habit of the variety and training system employed.  Indeterminate tomatoes grown in wire cages should be spaced 2½ to 3 feet apart, while a 3- to 4-foot-spacing would be appropriate for indeterminate tomatoes allowed to sprawl over the ground.  Determinate tomatoes can be planted 2 to 2½ feet apart.  Rows should be spaced about 4 feet apart.