Just teeing this up for gardengal.

LOL!! I am happy to offer my opinions but keep in mind this is coming from the opposite side of the country and I am by no stretch of the imagination a lawn 'purist'!

Let's take your questions in reverse order. Address the weeds first. And please don't use a weed 'n feed or combo product. They are unnecessarily expensive, a highly inefficient way to address weeds, harmful to kids and pets and a major source of pollution. Instead, use whatever broadleaved lawn weed killer available in a spray form and spray the weeds directly. Liquid sprays are typically safe for kids and pets once dry, don't leach into waterways and their use is directed only at the target weeds. Or remove them manually (often the best method when dealing with perennial weeds like dandelions or dock).

Once the weeds have been attended to, you can reseed if you must. But summer is really a very ill-advised time to do this. Northern lawns, which I assume you have, are comprised of cool season grasses that naturally want to go summer dormant. Encouraging seed to germinate and grow at this time of year may be counterproductive and will certainly require copious amounts of watering - seed must stay moist until germination and growth has developed. This is likely to involve more water more frequently than the existing lawn will be happy with.

I also do not recommend fertilizing cool season lawns in summer for the same reason.....dormancy and fertilization do not go together. But you could get by with an organic fertilizer as they are more of a soil enrichment process rather than a synthetic chemical injection delivered at the wrong time of year.

Personally, if this were my lawn, I would work on the weeds now, water as necessary during the summer months, provide a light application of an organic fert (if you like) to get the existing lawn as healthy as possible but wait until the end of August or early September before reseeding.

@gardengal48 (PNW Z8/9) Thanks so much for your detailed response. I like your idea of weed killer safer for kids and pets, but I have a lot of weeds, so not sure I may end of spraying the whole lawn. ? Most of my neighbors have a company -- Lawn Doctor ,etc. -- and they seem to be coming to put down fertilizer ever few weeks. Their lawns look amazing compared to mine, so i'm curious why you recommend not to fertilize.? And, in terms of organic fertilizer are you thinking of something like Milorganite? Thx in advance! .

Like I said, this is coming from a west coast perspective so may not be 100% appropriate for your needs.

Fertilizing a cool season lawn in summer forces it out of dormancy and amps up the need for watering. Most of the west coast experiences an extended period of summer drought in that it doesn't rain from midJune through to the end of September so watering a lawn becomes a critical issue that unnecessarily taxes limited water supplies. Many homeowners here just let their lawns go dormant....they revive on their own with cooler temps and fall rains. No intervention required :-)

No lawn needs to be fertilized "every few weeks". And lawn services tend to overdo ALL their applications because the are selling a product. The more product they sell - fertilizers, weed and pest controls - the more $$ they make. Local turf managers recommend 2-3 fertilizer apps - late spring, late summer, mid to late fall. And of those three, the last - mid to late fall - is the most important. And with an organic fertilizer, which are by definition slow release products, the effects are long lasting so fewer applications are necessary. In addition to the Milorganite, any seed meal - soybean, corn meal, alfalfa meal, etc. - will work as well. Or there are prepared, packaged organic lawn fertilizers you can purchase but they are expensive and don't necessarily work any better.

I am always a bit skeptical about a lush green lawn in the middle of summer. It usually signals a homeowner that is overly liberal with both synthetic, fast acting fertilizers and other lawn products and waters excessively. And I personally have issues with both of those practices - lawn care accounts for most of the groundwater pollution we experience as well as wasting water, which most do not realize is a very finite commodity (just ask any California farmers!).

But again, I am not a lawn purist and I am probably more tolerant of lawn imperfections than most :-) I use a mulching mower so never have had much need for any fertilizer. And I never water my lawn.

I just want to clarify a point gg made above, because it would appear to contradict things I've been saying for decades. She said, "No lawn needs to be fertilized 'every few weeks'." I do agree with that; however, what I have been saying, directed only to bermuda obsessives, is that bermuda loves to be fertilized every 4-6 weeks throughout the growing season. What that means is that bermuda might become slightly yellowed without continual fertilizer. 3x per year is adequate, but for those who must have the best lawn on the block, then they would want to fertilize every few weeks.

To the OP, lawn service companies only provide fertilizer, herbicide, insecticide, and fungicide. On the list of lawn management to-do items, these come far behind timely seeding, proper watering, and mowing. If you have a service but you are not pulling your weight on seeding in the fall (cool season grasses), watering (most important), and mowing (slightly less important than watering), then the lawn service is not going to work for you. However, if you are already doing the seeding, watering, and mowing right, your lawn is going to look pretty good from the git-go.

There are cool season lawn care gurus who do not water their lawns in the summer...or possibly ever. We cannot get away with that in most of the south, but for northern style grasses, it happens. Since these gurus have fairly nice lawns even though they don't water, a casual, or new lawn owner might think they can get away with not watering. I would suggest that the newer lawn maintainer do not take the watering shortcut for a year or so while they learn proper watering, mowing, and fertilizer methods and materials.

I'm not going to go through my typical essay on watering. You can search this forum for "deep and infrequent" and find it hundreds of times. Mowing should be at the mower's highest setting for cool season grasses, especially in the summer. I have seen some lawn gurus stop mowing and let the grass grow up as tall as possible beginning about now. The reason for that is that taller grass can grow deeper roots which penetrate to lower levels where the soil temperatures are cooler and there should be some moisture. There are also a reserve of untapped nutrients at the deeper levels. All this helps the grass survive both unwatered and unmowed in the heat of summer. Then when the summer heat breaks sometime in late August or September, you can bring the tall grass down with a string trimmer before mowing with a regular mower. There is a general rule against mowing more than 1/3 of the grass off at one time. If the grass is 9 inches long and you try to mow it back to 4 inches, that could be very bad. Instead trim it back to 6 inches with the string trimmer, give it a few days to recover, then run the mower.

I hope gg dissuaded you from seeding. Of the 12 months of the year to seed cool season grasses, July is the worst. Also, rather than killing off the weeds, I would suffer through the weeds and bare spots until September. If weeds come up there, fine - at least they are green. Their roots are also good for the soil. Mow them like they were the lawn. You can take care of them in September (for New Jersey). Then you can seed and move forward to a much better 2022 season. By seeding early after the summer heat, you have a chance to evaluate the new seedlings. If you need more seed, you'll have time. If you wait until October to seed, you don't have that window for more seed if it needs it.