My associate, K, and I are growing some plants now, see my Journal entry for more details.
A week or 2 ago, we noticed we had spider mites on a few plants, so after some research, K came up with this formula to kill them.
1 quart spray bottle, half full of water. Several ounces of 70% isopropyl alcohol, several ounces of vinegar, and an ounce or 2 of lemon juice. And a couple spoonfuls of baking soda. Makes a big pile of fizz when it hits the vinegar!
I can't give more exact measurements because we just eyeballed it. But it's been killing the mites very well and has not seemed to hurt the plants. K said using these ingredients was all natural, so we tried it.
So far so good! We'll be watching to see how it goes.