Tomato suckers are the side shoots that develop between the main stem and a branch. You remove these so the plant doesn’t get too unwieldy and because they reduce the size of your tomatoes. But instead of tossing them all away, root a few so you have new plants that will keep bearing into the fall. Wait till there are four leaves and remove the sucker from the plant. Place it in a 4-inch container of potting soil in a shady spot and keep moist. If you grow cherry tomatoes, you can this in August, too, to have young plants to grow indoors over winter.