Hi, Harry. Tomatoes have the ability to root all along their stems, so they actually benefit from deeper planting than most plants. If you've bought tomatoes in cell packs at the garden center, remove the lower leaves and plant as much as 75% of the length of the stem underground. Often the lower leaves have begun to yellow anyway, so it's easy to recognize which ones to remove before planting. You don't have to bury several inches of the stem when you plant; tomatoes are very adaptable so even if you only plant them an inch or two deeper, that works, too.