Above are the two teas I sometimes brew on sunny days. On the right, good old sun tea (in this case made from a black tea with apricot flavors). On the left, nicotine tea. This is what I use against severe insect pest infestations in the garden. I make it essentially the same way as sun tea: Throw some butts in a mason jar, fill with water, and let steep in the sun until it reaches the color I’m looking for (for nicotine tea this is a nauseating dark brown rather than the a pleasant amber I look for in drinkable sun tea), strain, and apply. If you are a nonsmoker and interested in trying this very smelly but very effective aphid destroyer (without the social awkwardness of asking a neighbor or friend for the contents of their ashtray or butt can) you can purchase small pouches of loose tobacco intended for hand rolling at most mini marts and bodegas.
Until this year I have never applied it to a food crop. Mostly this is because I haven’t had an infestation on a food crop until this year. However, something is chewing tiny holes in the leaves of our potato plants and I want them stopped! I was concerned that the nicotine could be absorbed into the leaves of the potato plants and end up in the tubers, giving us the potato equivalent of Tomacco. However, I have seen some trustworthy sites, such as this one, stating that it may be safe.
I want to note, however, that while I have had great success with this product on rosebushes against aphids, it had no effect on the pests attacking my potatoes. After some research it looks like what we have is tuber flea beetles (Epitrix tuberis). Actually, we had them last year, too and didn’t know it. There was no damage to our potato leaves but the crop was so dismally small that we announced it a failure and the one small handful of tubers we got out of two 20 foot long rows of plants was scarred.
I am currently researching organic controls for our pest and I will let you know what works!