My mother has hundreds (Thousands?) of cockroaches living in the cracks around her swimming pool. It seems they live off of, and love, the oranges, plums, and peaches that fall in the yard. They have never been seen inside the house, but have been outside all around the house. Generally, however, they stay close to the cracks in the pool.
How can I kill the little creeps. I’ve tried roach bait (helps a bit, but not much), boric acid (turns into clumps overnight), and sprays. Any suggestions?
I would get couple of chickens,they would eat them cockroaches in no time. 
Onthelist do you have any idea what type of cockroaches these are. Are they the great big Australian/American roaches, or one of the smaller varieties?
There are lots of different species of cockroaches and in general the ones outside aren’t problematic, unless someone has a serious phobia. They probably won’t come inside if it’s a species that is currently living fulltime outside. You’re far better of treating the house to kill the occasionally invader than trying to nuke your yard. There’s just no point I can see in killing off the local insect life
But if you have no environmental sensitivity at all….
You’re going to need some sort of powder. Concrete is just too porous and to alkaline for any commonly available liquid insecticide to be effective. Get down to your local hardware store and see what they have in the way of either granules, dusts or wettable powders. You will generally find that dusts and granules will be sold primarily as ant dusts, but they work just fine on roaches as well. Of course you will need some fine weather for powders to work.
Borax itself is fairly useless as a contact poison, especially outside where it absorbs moisture so readily. If you wish to you can try making a bait by mixing it 1:10 with sugar, but in general food baiting is ineffective against cockroaches when the have that much food available.
There are a range of pheromone baits available, but availability to the general public varies from location to location and they end to be expensive, but they are astoundingly effective. If you have the money and can find any these are the way to go.
Are you sure they are not Palmetto Bugs? Yeah, they are still just giant cockroaches that can fly. Evidently, your mom has one or more nests of them in the cracks around her pool. They tend to stay outside, especially if there is abundant food and water handy.
There is probably no cheap way to get rid of them. From your description, they sound like they are pretty well ensconced. Get an exterminator; direct his attention to the pool are; and then have the cracks around the pool sealed. Keep the fruit off the ground and you might want to drain the pool for a while. Make sure the exterminator treats the entire perimeter of the house also because once the food and water sources are gone, they will come indoors to find food.
HEY!!! How about the CHICKENS!!! :mad:
A “palmetto bug” is an American Cockroach. Periplaneta americana, I think. Give it up. It’s a flying roach. I have this argument with my mom all the time - she likes to think that if she calls them palmetto bugs she can deny the fact that the giant roaches come in the house sometimes.