gardengalrn, I also live in Kansas and I'm an RN. I used to fight weeds in our veggie gardens also. I mulched with little benefit no matter how thick I spread it. I then tried laying a layer of newspaper on the soil and covered that with mulch (I use grass clippings and shredded leaves). The first time I didnt use thick enough layers of newspaper. Weeds came back after several weeks. With thicker layers it was effective all summer. By the next spring the mulch and paper had decomposed and were tilled in, benefiting the soil :) This year I used newspaper in some areas, brown paper bags in others and cardboard in others. I can honestly say I had a weed free veggie garden :) Laying down the newspaper/cardboard is a bit time consuming but well worth it. I place the barrier right up to, but not touching the stems of plants. My neighbors give me the leaves they collect in the fall and in the spring I run over them with the mower...using the collection bag...this is spread over the newspaper/cardboard. I'm so happy I have found a way to enjoy my veggies garden and not be overwhelmed with weeds. As for Preen...I use that only in flower beds. I sprinkle it after I put a good layer of mulched leaves. It lasts about 3 months. You can successfully plant seeds in the area. There is a long list on the back of the box of seeds that are not effected by the product. I just checked my box and green peas are listed as not being effected by Preen. There are a number of other veggies that it is safe to use with as well as grasses, flowers, shrubs, trees, ornamental grasses, etc. Great product...I just choose not to use it on things I'm going to eat. With a little preparation you can spend your summer enjoying your garden instead of fighting the weeds :)

The single best "weed" growth preventer you can use is a good, heavy mulch. I have not found a reason yet to spend my money on "stuff" that will kill "weeds". Any preemergent "weed" killer you use will stop all emerging plant growth, even those you want to grow.

Basically any preemegent should be fine. However, it won't have any effect on your nutsedge. That is a perennial weed and will come back from the "nut" and multiply quickly. You will need to either dig out those weeds or use a post emergent specifically designed for nutsedge.

Herbicide Safety and Weed Control Comparison in Spring Seeded Kentucky Bluegrass "Early spring preemergence herbicides are often necessary in Indiana to prevent troublesome annual grassy weeds such as crabgrass and goosegrass. Additionally, these applications help to prevent the emergence of some broadleaf weeds. Most preemergence herbicides work to kill weeds by preventing cell division causing death to weed seedlings shortly after they germinate. All preemergence herbicides (except Tupersan) work to prevent the emergence of turfgrass seeds as well as weed seeds, so a turf manager cannot use a preemergence herbicide if they plan on seeding in the spring. As mentioned, Tupersan (siduron) may be used for preemergence control of annual grassy weeds in newly seeded cool-season turf. Another strategy is to use a postemergence herbicide instead of a preemergence herbicide to control crabgrass and other weeds in late May and June that is safe to use on seedling turf. Options include Drive XLR8 (quinclorac), Quicksilver (carfentrazone), Tenacity (mesotrione), and SquareOne (quinclorac + carfentrazone). These products can be most safely used very soon after seeding to control crabgrass (see label for exact details on each turf species). If the seedlings are more mature (have been mown 2-3 times following their emergence) then other products such as Q4 Plus (quinclorac + sulfentrazone + 2,4-D + dicamba), Onetime (quinclorac + MCPP + dicamba), or Solitare (quinclorac + sulfentrazone) can also be used. The objective of this experiment was to evaluate herbicides at three different application timings for use in establishing Kentucky bluegrass from seed in the spring."