One of the henbits; Lamium purpureum or L. amplexicaule. Pretty purple blooms but once you see the purple color you are sure to see it again next year. These are winter annuals that need to be controlled first in the fall and then again in the late winter (chemically, which you can't). Looks like some control has already been applied by maybe extreme winter cold or severe drought??? (scorch on leaves) but not sure. Doesn't seem to do well competing with healthy turf, so overseeding in fall and thickening the turf may be a help. hortster

The easiest way to ID weedy grasses is from the inflorescence, the seed producing stalk. Compare your weed to Dallisgrass, you could also try asking on the grasses forum or Name That Plant. Good luck!

Another option is Gordon Ornamec 170, it's cheaper than 2 bottles of the Bayer and will last you many years. It's also good for other tough weeds like quackgrass and dallisgrass. https://www.amazon.com/Ornamec-170-Herbicide-32-oz/dp/B008MZQE6O/ref=sr_1_1?ie=UTF8&qid=1470488280&sr=8-1&keywords=ornamec+170 Yes, you will need to apply a pre-emergent. I recommend prodiamine, it will control this and most other weeds.

I think you might be safe ignoring our typical warnings for summer applications of anything. How often do you get temperatures above 85 in the summer? If your temps typically run in the high 70s to low 80s, then you can do what you want. You have what the rest of us would consider to be fall type weather while we're suffering in more heat. The white flowered plant is Dutch white clover. The yellow flowered plant is black medic. Between the two of these weeds, I would much rather live with the clover. At least it becomes dense and looks fairly lush. Black medic just looks scrappy. To eliminate these completely requires something like Weed-b-Gon Chickweed, Clover, and Oxalis Killer. If you think you can get rid of these organically then you'll have a future of internal conflict with reality. The mix you are using with vinegar will kill the tops of many plants, but only rarely kills the root. Plus it works best on hot sunny days...which you don't really get up there on the lake. I am a 100% organic fertilizer kind of guy and have been for 15 years. At the same time I see the value to having a nice lawn with no weeds. What you might consider is using the chemicals one or two times up front to get rid of them, then follow that up with a grass "densification" program to help keep weeds out in the future. Reseed the thin areas with Kentucky bluegrass. KBG is the kind of grass that will spread to fill in thin areas in the future. In your area it may go through the summer with only rainfall. Otherwise, it may go dormant in the summer dry spell and/or heat, such as it is in Racine. Fall is generally the time of year to reseed northern grasses. In your case you might start toward the end of July and get good results. My organic fertilizer of choice is alfalfa pellets (rabbit chow). I like it because it is available at every feed store in my area, and it works. You might find that something like soybean meal, corn gluten meal, corn meal, cottonseed meal, or Milorganite is more available to you. Certainly Milorganite is available in Racine!! The application rate for all of these is 15-20 pounds per 1,000 square feet. You might be able to get a discount on a pallet for your acreage. If you live in an affluent area and want to keep your lawn up to their standards, it's going to cost you some money.