Plant AheadCanâ¤™t wait to see your flowers add color to your garden or lawn? Then be sure to plant their bulbs as early as now. Flowers like crocuses, irises, and tulips actually need the winter freeze to start their growing process, so autumn is actually the ideal season to plant them. However, be sure to do so while the temperature is still in the forties and fifties, not when the ground is already frozen. Feed Your GrassItâ¤™s not just plants and flowers youâ¤™ll be saying â¤˝goodbyeâ¤ to come winter; youâ¤™ll be bidding adieu to your turf grass as well. Unlike the former two, though, grass continues to grow roots until around 40 degrees. If you apply a high phosphorus mix (about a 12-25-12 ratio) in the fall, they green up faster in the spring.