We have been having this prob. at my house. We just moved into a brand new house that seemingly was already occupied by a whole lotta spiders including the black widow! I almost ran into one that was hanging down in the doorway of my closet. So anyways we have been doing a lot of research and here's what I've come to learn. Only the females are poisoness. And if an adult gets bit by one it's prob. not going to do much. It could, but not super likely. It's the babes and kids you gotta worry about. It can be lethal to a small one. So once I saw two in my house and two on the outside I made the difficult decision to call the exterminator. I was bummed b/c I have been diligent not to use toxic chemicals in my house, but I am more worried about a black widow bite then using chemicals that ppl use all the time. The exterminator said it was eco friendly and would not harm ppl, but of course we got out of the house the night he sprayed anyways. He also told me that you cannot just spray for spiders and hope they run through the poison, you have to find the actual spider and kill it. a lot like following a trail of ants to their nest to kill it. Spiders are not like roaches. They will not just run through the poison then go back to their web and lick their legs to clean themselves, therefore ingesting the stuff and die. You have to find them, their web and their egg sacks. Black widows like hidden places, like deep in cabinents, under awnings, in the garage behind boxes, in boxes etc. You can buy stuff at places like home depot I'm sure, but I didn't want my dh diggin around looking for them so I let the professional do it. If I hadn't seen any on the inside I might not have worried so much but I couldn't handle it once I knew they were inside too. Please be careful. Hope this info helps even though it was not the natural root you were looking for. I have personally spent the last few weeks living spiders which I absolutey hate and am horrified of.