Typical recommendations state that you should transplant at the same level as in the container; however, tomatoes are different. Research conducted at the Southwest Florida Research and Education Center determined that tomatoes planted to a depth up to the first true leaves yielded a greater harvest than those transplanted only the depth of the root-ball or covering the cotyledon leaves. However, deep planting in northern climates early during a cold wet spring may not lead to increased yield and may lead to root-zone diseases.
Some home gardeners purchase long overgrown tomato transplants at a discount and lay the whole plant lengthwise in a shallow trench. At each node, roots will appear and a new branch will elongate. You can then separate the new plants and transplant them to a more appropriate spacing.
