North: Zones 1, 5, 6
Having a nice established lawn requires 4 Fertilizer's a year, over-seeding in the fall as needed, and proper lawn maintenance. First is keeping your lawn clean of debris and thatch. When there's debris and thatch it's holding moisture creating bug and fungus problems for your grass. To maintain a clean lawn do a spring and fall cleaning every year, if you have kids make them get out there and do it :)
Your two main fertilizers start in the with pre-emergent crab grass controls, one in March-April and another 6 weeks later in May. Spot treat weeds with a concentrated spray rather than doing a weed & feed, this way you're not stressing the grass out where there's no weeds; if you have a yard full of weeds do a weed&feed then get into the habit of spray killing from there on out.
During the summer you can apply a fungicide and/or insect control depending on the weather conditions. Around here the humidity and moisture tend to cause some fungus and/or insect problems so it's smart to apply a preventative before it happens. The preventative usually gets applied in May-June.
Fall is the best time to over-seed your lawn because the ground is warm for quick germination and the weather cools down making optimal growing conditions. We recommend aerating your lawn first loosening the ground followed by an over-seed. Over-seed rates range from 2-10lbs per 1k sq. ft depending on what your lawn looks like. If it's looking good you can go very light just to fill in any spots. If it's looking decent but needs an over-seed you'd go the traditional 3-5lb per 1k sq. ft. If it's looking rough than you can apply seed at a slightly higher rate of 6-8lbs per 1k sq. ft. Starting from straight dirt requires a 10lb per 1k sq. ft rate.
Winterizer is the last fertilizer of the season which gets applied between October-December depending on the weather. Around here I tell people between Halloween and Thanksgiving is optimal. Easy rule of thumb is to apply the winterizer after putting your lawn mower away for the season.
•Rake up debris and leaves from winter.
•Growing season starts. Mow grass 3 inches high. Leave clippings on lawn (optional).
•Apply first dose of fertilizer. (Step #1 Slow Release Fertilzer with Pre-Emergent weed control)
•Treat for weeds/crabgrass with pre-emergent herbicide or eco-friendly corn gluten.
May - June
•Spot-treat dandelions or treat whole lawn with post-emergent weed control ONLY if you have a yard FULL of weeds (Step #2 Slow Release Fertilizer with Lock-Up Weed Killer)
•Fertilize six to eight weeks after Step #1 fertilizer. (Step #3 Slow ReleaseFertilizer with Pre-Emergent crabgrass control)
•Water if rainfall is below 1 inch a week.
•Treat for grubs using beneficial nematodes or grub control. (Step #4 Slow Release Fertilizer with 2-way Insecticide for surface insects AND systemic grub control)
•Dethatch and aerate with core aerator when rains resume and ground softens.
•Fertilize and seed. (Step #5 Core Aerate, Over-Seed, Starter Fertiizer, and Lime)
•Fertilize six to eight weeks after last feeding. (Step #6 Winterizer Fertilizer)
•At final cut, after a few frosts, mow 2 inches high.