You also get the wisdom of the ages and people who might not have the same experiences. The advice I gave is based on years (and years) of reading and moderating forums for amateurs and professionals. Applying fertilizer on Memorial Day might be too late in your area due to the onset of summer heat, but as a starting point, it is a very easy date to remember. Whether you get disease or not depends also on grass variety, air circulation, dew, humidity, soil type, and other factors. I'm not sure why Georgia would be much different from other places where the taller grasses are the healthier ones. At the same time that the wisdom of the ages sounds like a good idea, you also get the senility of the aged. Tupersan is relatively new to my repertoire of garden products. I became 100% organic before I heard of it and seem to have a block about that product. In general I don't put any faith in preemergent herbicides but people I respect tell me they work. I do recall from my relatively recent reading that Tupersan works as tiemco says. Professional grass growers (livestock producers) fertilize with 1/4 of their annual nitrogen in the spring, and they always apply it after the initial flush of green growth has ended. They apply 3/4 of the annual nitrogen in the fall. They do it this way to minimize their mowing workload and to spread the productive growth along throughout the entire growing season. The wisdom of the ages here at GardenWeb also agrees with tiemco that combination fertilizer/weed killer products are not going to do what you expect them to do and it is better to use different products for the different requirements. Yes Mother Nature has Her own ideas about watering, but for what you do, you do not have to encourage weeds. Far too many people set their sprinkler to operate for 10 minutes every day. That schedule is going to germinate every seed in the garden. You have control over your own watering. Allowing the soil surface to dry out as much as you can will develop deep, drought resistant roots as well as minimize weed seed germination.

I would suggest you not use any broadly applied herbicides or pesticides this year. No sense chancing stressing the turf. and at the very least check the label for advisories regarding applying. A half pound/k of NPK every two weeks applied to dry blades and then watered in until mid June will be beneficial for the sod. As far as fertilizing new sod or grass, what follows is the best advice I've ever found: "The Philes Phertilizer Lecture follows: These new KBG lawns are hungry for fertilizer. Very much like, (and if you renovated, exactly like) a sod farm, those guys that start with bare ground, throw some seed around, and by late July of every year, they are selling product: a deeply rooted, dense intertwined dark green carpet of lush (no bare spots) Kentucky Bluegrass. Now how do they do that every year? (And, of course, the implied question "How come you and I can't do it also?") They do it with frequent, rather than heavy, applications of fertilizer. Literally, every two weeks, a light application of fertilizer. At seeding time, they start with an 8-8-8 or a 10-10-10. Upon the grass reaching the 'first mow' stage, they add Milorganite, and then it's Milorganite every two weeks, as the weather gets warmer. Every two weeks would seem to you (and in the old days, to me) as 'excessive'. It's not. Not only is it not excessive, it may well be Required. There's only one difference between the sod farm, with that lush green grass for sale every year, and the typical homeowner here (I'm leaving out the general public: the public is a 2 or a 3, as you know, and you guys and gals are a 6 or a 7. Twice as good. But I'm trying to get y'alls up to a 9, which is where the sod farm is), and that difference is Frequent Applications of Fertilizer. Especially with KBG, more fertilizer than you are used to putting down is good. A typical homeowner would fertilize once in the fall. Not the first year, but every following year, on these newly renovated (or overseeded) KBG lawns, two full applications are required in the fall. Spring? A lot of people don't like to fertilize in the spring. A KBG lawn requires an application of big-first-number fertilizer, in May. A newly renovated KBG lawn requires yet another application in mid June. That lawn needs the nitrogen, for all the growing, both above, below, and across the ground, that it's wanting to do, and will do, if you feed it. Density? It requires nitrogen. Color? Requires more nitrogen. Aggressiveness? You already know what it requires. Even an old KBG lawn, the Merion sods of this world, needed more nitrogen than they received. As proof, drive through the subdivisions of ten or twenty years ago, and look at the lawns: those lawns were not exactly treated like a sod farm, were they? If you want your new lawn to turn out just like that, here's all you have to do: fertilize once in the fall, and once in the spring. That's it. The results are guaranteed. By now, somebody is saying (and should be), "Is it possible to OVER fertilize a lawn?" Yes, it's possible. But not what you'd think. The 'typical' overfertilize stripes that we all seem to fear came from the old drop spreaders, when the rows were overlapped. That overlap caused a doubling of the fertilizer along that narrow, overlapped row, and it was all delivered in one day. What most people forget, while imagining the scorn of neighbors and children, is that those bands of over fertilization did not last until fall, they went away in less than a month. Repeat: the so called over fertilization went away, in less than a month. The homeowner had not created another Love Canal toxic zone, the homeowner had instead managed to put down more than the grass could handle all at once, but in fact the lawn handled it, and probably even needed it. The lawn just didn't need it all at once. Nor in summer's heat. Disaster? No. Bad delivery technique? Yes. It wasn't too much fertilizer, it was too much fertilizer all at once, and there's a difference, isn't there? These days, with the rotary far-flinging spreaders, a more evenly spread application of fertilizer is the norm. Now that we want to emulate the sod farms (and their turf success), we know that there's no sin in putting down a half application, in one direction, and putting down the other half application, in the other direction a week later. Now that we want to emulate the sod farms, we will want to feed the lawn during summer, rather than letting it starve while it battles the hot summer sun. So Milorganite, or other organic fertilizer is required, rather than a big-first number fertilizer. At least once in summer, but if you've renovated, or over seeded, that new KBG needs two applications. It needs the food. So there's my recommendation for the renovators and overseeders: two applications in the fall (not the first year, on the seedlings, they can't use the food yet, as they haven't grown enough yet) at least one application in the spring (two if you renovated or overseeded. That application we skipped last fall goes down the following spring), and you must feed the lawn in the summer: that new KBG needs the food. So here we are, end of August. You know you are going to fertilize in the fall, probably twice, and perhaps didn't do enough during spring or summer. You can do a half application right now, of big first number fertilizer, or a full application of Milorganite. And still do the regular fertilizing when fall gets here. But your lawn likely needs the meal, and if you provide that light meal right now, before fall gets here, I think you'll love the visible results. Good luck with it."

I would not mow it at all unless it gets up to 5 inches. What you need to develop in the winter is deep roots so the grass can withstand the summer heat. Grass kept short will develop short roots. Tall grass has more chlorophyll to make more sugar and can develop deeper roots. Set your mower to the highest setting and wait until the grass is tall enough to mow. As for your fertilizer, I'm a little offbeat with most here. I think applying fertilizer along with the seed is a waste of money. Fertilizer does not work unless you have roots to suck it up. Seeds have no roots. In fact I don't think your roots do much of anything except absorb water until the grass gets tall enough to mow (5 inches). I always suggest you wait to apply fertilizer until the second time you mow (at 5 inches, not to beat this horse any more). By then you have some deep roots and your fertilizer will be absorbed as it moves deeper and deeper in to the soil. Getting back to the specifics of your question, it sound like you are mowing too low. Assuming it has been mowed once already, I would let it get taaaaall enough to mow once more and fertilize.

Where do you live? What kind of seed did you put down? Did you use a starter fertilizer? What is your watering program - how often and for how long? Lawn care is as easy as watering, mowing, and fertilizer. You're already overthinking it. This is the right time of year to seed a northern grass to minimize weed issues. Had you come here before seeding we would have suggested you water the bare soil daily to sprout any new weeds and then spray those out with RoundUp. Then you could seed without fear of getting weeds. But here we are. If you have broadleaf weeds in the old lawn, spot spray with Weed-B-Gone. If you have chickweed, clover, or oxalis, you'll need Weed-B-Gone Chickweed, Clover, and Oxalis killer. It's a different, stronger, product. It will not harm the old grass, but read the label for instruction around new grass. Forget about weed n feed products. They usually don't do what you expect them to do. The problem is when you need weed killer you don't need fertilizer and vice versa. If you want to fertilize now I would use an organic. You can use that at any time even on the day you fertilize with a chemical fertilizer. They do different things for the soil and plants. You can use the organic over the new and old lawn at the same time and at the same rate. Start with 10 pounds per 1,000 square feet. In 3 weeks you can reapply at the normal rate of 15-20 pounds per 1,000. But you do need to spot spray the weeds in the old lawn. Then around Thanksgiving or so you can fertilize with a high N fertilizer for the winter.