Get your garden tomatoes off to a great start by helping them create a strong and complex root system in the garden. That means you’ll have to bury up to 2/3 of the stem! Horticulturist Sheridan Hansen, with the Utah State Extension, show the right way to plant a tomato plant. Tomatoes need fertilizer that is higher in phosphorous than it is in nitrogen. The numbers “7-22-8” in Sheridan’s fertilizer reflect the amount of nitrogen, phosphorous, and potassium, respectively.