In Cold Climates, Keep watering your lawn in late fall no matter how much snow you anticipate. Cold temperature creates desertlike condition, with the freezing ground locking up water in ice and making it impossible for the grass roots to drink. Aeration allows air circulation & water for the roots to drink.

In the spring when crabgrass and other weed seeds begin to germinate, aeration is the best thing to get done followed by so called weed and feed product which combine fertilizer with a pre-emergent herbicide that keep weed seeds from germinating.

There's also an organic alternative called corn gluten, which like the chemical herbicides keeps crabgrass seeds from coming to life. As the gluten decompose, it adds nitrogen to the soil.

How green is your valley? Not green enough? Epsom salts, which add needed magnesium and iron to the soil, may be the answer. Add 2 tablespoons (30 ml) to 1 gallon (4 litres ) of water, then spread it on your lawn. Afterward, water it with plain water to make sure the mixture soaks into the grass.