First thing I would do is put the feet of the cribs in jars or plastic bottles. Bark Scorpions are excellent climbers but can't climb straight up glass or smooth plastic. People used to hang plywood over the cribs that was larger then the cribs. That way, if a Scorpion fell from the ceiling, it landed on the plywood. If it ran off the edge of the plywood, it would hit the floor and not the crib. Go to Home Depot and ask about a fluorescent black light for Scorpions. They will know what you want. It's basically a 12" battery operated closet light. You buy that and a black light fluorescent bulb to fit it. The incandescent bulbs don't work (the ones that screw into a regular fixture). Scorpions will glow very brightly under the black light and be easy to spot. Sweep the babies rooms every night. They generally won't move until you touch them, so they are easy to catch. They are fairly quick once touched, so plan carefully. I use tongs. You can drop them in vinegar to kill them. Have your home sealed, or do it yourself. You'll see ads in the local papers for Scorpion control. Especially check around the pipes under your sinks and seal those openings in the drywall. Read the article from U of A that was previously posted. In addition to removing their habitat outside, the house sealing helps a lot. Scorpions haven't been studied all that much relative to other insects, so there is a lot of misinformation about them. I've read every book and article I could find. Bifenthrin is the most effective pesticide that I have found for Scorpions. It will kill them, altough you'll hear people say that nothing can. It is also safer for people and mammals then many others. Talstar (a brand of insecticide) is expensive, but I highly recommend it. You can order it online or ask your pest control person to get it. You used to not be able to find Bifenthrin in the stores, but now I see Ortho is using it in their granules (not liquid though) for Fire Ants. I would water in the granules in a ring around your home and around your property. I would also spray your tree trunks, although no pesticide company I've talked with even knows this. Bark Scorpions live in trees. They love palms and pines. Make sure you cut back any trees that overhang your roof. I didn't completely stop seeing them until I began spraying the tree trunks. My property was infested with them when I bought it. On one collection hunt, my son and I picked up 147 of them! That's what drove my self-taught doctorate in Scorpion eradication. I know see about 1 per year. They are fascinating creatures and lots of people keep them as pets. I'm fine with them in the wild, and even avoid stepping on them. In my house though, I view them as any other intruder.

Your soil must be mostly clay. The trouble with clay is that it clumps and doesn't let the moisture drain away. Too much moisture and soon your impatiens start to rot. Add organic matter--manure--at least 3 years old or the bagged stuff. I've discovered a new product that is called composted manure and I use it every where. You can add compost or leaf compost. You can also add kitty liter--the cheap nonclumping kind. This is made of baked clay, like terra cotta pots only in pellet form. It gets between the particles of clay and separates them. Work all these things into your clay. and you will have a better growing medium. Add some organic matter every spring or fall after that and soon you will have well draining loam and your impatiens will thrive

Since nematodes and Milky Spore are expensive and you mentioned it was out of your range for a large lawn, I'd go with the grub killer. No, it's not organic. It's not an optimal solution. You know that already. I don't know how specific Merit is, but if it's a general insecticide you do run the risk of wiping out your micro-arthropods that happily do a good job keeping your lawn disease and fungus free. (Sometime, lookup the lowly fungus gnat...they're one of the most amazing and unconsidered creatures in our grass and gardens!) But if you gotta, you gotta. It's kind of early for the grubs to be back in Zone 5b (I'm a 5c/6a crossover). And when they do, they're third instar and about to become adults. There's no reason to try killing them now because it won't work very well. I'm not sure what the bag recommends, but the one time I was forced into using (gag) GrubX I applied it about two weeks before I expected to see the adults. The next year, no grub damage (on my parents' lawn at the time). Maybe you could start a small fund for next year for Milky Spore? It works fairly well in our colder climate--grubs counts on my current lawn and in the gardens were already dropping last fall and I expect far fewer still this year. Plus it lasts years until it micro-evolves to a less-killing genome. Then you just reapply.

Mother-in-law plants. In my DH's office reception area there was this huge row of those plants, perfect condition, and I kept looking for a window to make them grow. lol. They did great with fluorescent lighting. They're succulents so they need watering maybe once a week. Once the "leaves" start to feel soft is when they need watering. Snake plants are good too.