Let's put seeding a new lawn aside for now and talk about renovating an existing lawn. Do you have patches that have died out due to disease or insects? How about a lawn that is being overrun by weeds, particularly crabgrass? To say the least, it has been a banner year for crabgrass and broadleaf weeds. First we had very droughty conditions which made grass go into slumber mode. Then came lots of rain, heat and humidity- ideal conditions for crabgrass EXPLOSION! And did it ever!
So what do we do now? It's too late to apply a selective weed killer (kills weeds, not grass), especially if you want to take full advantage of the best time of the entire year (now!) to seed grass. So here are your two options:
1) Hand weed out all crabgrass and broadleaf weeds. This is my personal go-to. I never look at the depressing total picture; rather I look at an area about 10' x10'. I leave all the good grasses and clover (I love clover), and pull or dig out the rest. Before I know it, that small area is clear of nasties. Voila, and I'm ready for the next 100 sq. ft. An added advantage to leaving the desirable grass is that its holds the site better when it rains heavily.
2) Apply a nonselective herbicide which kills everything including good grasses. If your weeds are annual and not super-established, a natural herbicide such as Burn-Out works quite well. Your conventional choice is a straight glyphosate such as Kleen-Up or Remuda. The beauty of such a product is that it quickly breaks down in the soil and leaves no residual. That means once everything is dead, you are ready to rake out the debris and start the seeding process.
Note: There is a lot being said about glyphosate these days with regard to health risks. We use glyphosate cautiously- never when windy and never near a water source. We wear protective clothing at all times during application and use it only when necessary. It is never applied in the vegetable garden or in perennial beds where flowers occur. With these cautions in mind, a straight glyphosate is a very handy tool.
Before you start the seeding process, it's important to know your soil pH. A reading of 6.5 is ideal. Below that, it is beneficial to apply a minimum of 50 lbs. lime/1000 sq. ft. worked into the soil as deeply as your condition allows. Then lightly rake a starter fertilizer into the top inch or two of soil. Because most soil tests are showing high levels of phosphorus, I am very comfortable using Blue Seal Safe 'N Simple Lawn Food as my starter. It's all natural and won't burn. It's 6-2-4 analysis is the perfect 3-1-2 ratio grass most appreciates. Call me crazy, but I use my garden fork to aerate to a depth of 2 inches. Yes, it's a bit of an arm work out, but it puts my fertilizer and/or lime down where I want it. Now I rake the site smooth and seed at 600 sq. ft./lb. Then I lightly overseed with white clover, the great survivor. Because of torrential downpours lately, I'm lightly covering the seeded areas with Lucerne, a heat-treated chopped hay and straw combo. This prevents erosion, holds moisture when needed, and has little or no weed seeds in it.
So don't hesitate to get the job done now. This is the beginning of the growth cycle for grass and, thus, the optimal time to seed. You will then have all the way until the ground freezes to get real establishment. Plus you will be right on schedule to participate in our ever-popular Blue Seal Safe 'N Simple lawn care program in the spring!