When nighttime temperatures are consistently warner than 60°F it will be time to plant tender crops such as eggplant, melons, squash, and zucchini. Prepare the planting spots these crops by for digging holes 12 inches square, 12 inches deep, and 3 feet apart. Add a forkful of well-rotted compost or manure to the bottom of the hole and then refill the hole. Draw soil from the surrounding area to form a mound over each hole. Sow three seeds on each mound. When the seedlings come up, clip away the two weakest and leave the strong seedling to grow on. If you are planting starts, set one on each mound.