You can find better pre-emergents at suppliers like John Deere/ Lesco (they've merged) than the home improvement stores. I agree with dchall, in my own findings granular pre-emergents don't perform as well as the liquid. The field testing that that the manufacturers site (so take that with a grain of salt) suggest that they perform about the same. If you're after grassy weeds, such as crabgrass, dimension is a great pre-em. If you're seeing a lot of both grassy and broadleaf, Prodiamine is a good alternative. The advantage with Prodiamine is that it is much cheaper to manufacture and has a number of generic versions. The 2-4D that Dchall mentioned is definitely a safe alternative in cool-season grasses for broadleaf weeds. Another, if you have trouble with crabgrass this season is Quinclorac. Quinclorac has the major advantage of being safe on Fescue even when it has just been seeded. To my knowledge it is the only herbicide that can boast that. If you mix it with a methylated seed oil, you have a good crabgrass control. The only odd exception is crabgrass that is in the intermediate stage, between newly emerged and mature quinclorac won't give any control during this period. As for the bright green grass, it isn't uncommon when you've been seeding so see color differences. Tiemco is correct about KBG being a dark green when it matures. There is a definite possibility that what you've seeded has come up much darker than what was there before. I ran across this today with a Fescue lawn that I seeded last Fall. The cheaper Fescue that was in the lawn looked much brighter than the cultivars that I used which included Speedway, Davinci and Blackwatch. So it's entirely possible, that the brighter colored grass was a lower quality Fescue, such as K31 that was there before. All the same, make sure that you don't over-do the seeding, which can lead to over-crowding and cause die-back or pythium blight in the up-coming months. Also, it's good to use a blend. There are a number of improved varieties of both bluegrass and fescue on the market today, which offer advantages over the older cultivars. For example, you can buy a mix of thermal blue, which is 10% bluegrass and the other 90% is made up of 3 different Fescue cultivars. It's highly drought tolerant and disease resistant. Either way, good luck and thanks for sharpening our skills with your question.

Use BONIDE WEED BEATER ULTRA and I bet anything you will kill it. It will not kill your grass. You can use it in temperatures as low as 45 degrees.

There is no treat-and-forget solution where it has been well-established in a lawn. It requires constant vigilence like being a lawn security guard. I've tried the oxalis-destroyer but fear it has made matters worse. The problem is that the chemical stresses out the lawn grass while it is attempting to control its targeted foe and a stressed lawn makes it that much easier for any weed to take hold. So you may need to just live with a slightly brown lawn until the violets have succumbed. Fall treatment followed by the following Spring is the best success and figure on a few years followed by close monitoring and more treatments when new eruptions occur. Use a surfactant to help break the wax (yes, the violet leaves have been preparing for our attack for thousands of years). And before you violet sympathizers begin to suffer the effrontery of eradicating this natural botanical... try to understand and sympathize with the lawn maintainers. Homeowners who spend years planting and caring for a lawn (in this context, "lawn" means grass!) resent any invader that seeks to undo all their efforts and expense which created the lawn in the first place. It's not the occasional tuft of violets that is at issue but rather an entire lawn covered to the point where the grass has been all but eliminated. If we wanted a field covered with violets we would have planted them in the first place. And trying to bag clippings is near impossible because violet leaves do not shear like grass and discharge through the chute. They create a slurry of green sludge that must be removed from the bag by hand or with a trowel. There is a difference between coexisting and invading. Wild violets are about as invasive a weed as there is and confounds lawn care all over the country. They have ceased to be "cute" additions to a cultured environment.

Pre emergence is the first step in having a good lawn. This step will stop all seeds from germinating. I do not know where you live, but fertilization at the right time is important. Milorganite, is in my opinion one ofthe best fertilizers for the Homeowner. The UMBC has even stated that it also acts to repel Deer. Not fully though. Turf Trust is also a great product also. Hmm if you go to http://www.turftrust.com/ . Scroll through the pictures and you will see my lawn, which has a shed. But, remember 50 years ago people did not fertilize they used clover to add nitrogen to the soil. Grass and clover lived in harmony. Clover is a bite to get rid of. Any, Weed killer for the lawn is usually OK. You may need a few applications. I like Weed Beater Ultra. Now after all this. Reseed in the fall. Not in the spring.