Paging Snopes.com and/or Mythbusters; Wanna Do A Gardening Episode?

Actually, Mythbusters already did a gardening episode. It was awesome! And not just because it was also the episode where they used bug spray to blow up a house.

This question started off (via Facebook) with a girl I went to high school with, who asked about deer- and mole-proof plants. From there, we acquired a few more participants in the conversation, and branched off into repellent options. Everybody who's been gardening for more than five minutes has heard at least a few of these. Feel free to contribute yours in the comments! I'd love to collect and maybe test the as-complete-as-possible list.

Q. Is it rabbits that don't like marigolds? My grandfather always took hair clippings and scattered them around the perimeter of the garden . . . he swore the scent kept the deer away.

A. A lot of critters don't like marigolds and won't eat them, but as far as repellent goes they're mostly effective with certain bugs, so I think people tend to generalize that principle to everything. There really needs to be a lot more research on this stuff, but everybody's busy testing pesticides (not an entirely fair/accurate statement; more on that later).

I've been working (well, volunteering) with a lady who sells plants, and she says a lot of people swear by celosia for deer repellent, which I'd never heard. The hair clippings MIGHT (?) work for deer, but I doubt it, and I know from experience they don't work for woodchucks. Another thing I've heard is to put pee around your garden. Yes, human pee. Only works if you're a carnivore/omnivore, though. Critters aren't scared of vegetarians. Again, more research is needed. Can you imagine writing THAT grant?

General rule of thumb: deer and other wild critters will leave your plants alone as long as a) it's difficult for them to find them (hence my policy of interplanting things rather than having separate beds of a single crop, when possible), and b) there are plenty of other things for them to eat. When you're the only greenery around, though, or at least the tastiest greenery, some snacking is inevitable. About the only thing that works reliably for deer is very tall, properly placed fencing. About the only thing that works for rabbits/woodchucks is the same fencing, only set so it extends quite far underground. Moles? Container gardening might be the only sure-fire solution.

Also effective (not so much for moles, but for larger pests) is what one of my former employers calls the "hot lead method." Not generally practical for urban agriculture . . . .

Basil is having a rough week . . . .

First Dr. McGrath, a plant pathologist from Cornell (and the reigning goddess of integrated pest management for fungal diseases), is quoted as saying if you see the new strain of downy mildew on your basil, it's best to just go ahead and make pesto NOW . . . and then Becky gets Japanese beetles! Poor basil.

Q. Hey, how do I keep Japanese beetles out of my basil?

A. You have two realistic options. 1). Don't plant basil, 2). Hand-pick and drown the little fuckers (um, the Japanese beetles, not the basil).

Two other possibilities. From a long-ago forum conversation over at davesgarden.com, I think: smoosh up a bunch of dead Japanese beetles. Add water. Strain and spray on plants. The jury is out on whether this works, and whether (if it does) it's due to the redistribution of pathogens specific to Japanese beetles, or if, as one forum poster put it "They come up and go OH NO it smells like Uncle Ed and then leave." And, from my own brain: find something that Japanese beetles like MORE than basil, and space it around your basil in pots so that they all go there. Then, either remove the pots (bugs with 'em) or hand-pick and keep using them. Actually, the basic concept isn't mine--it's called trap cropping, and works great with some bugs (e.g., supposedly, crucifer flea beetles). Problem is, I've never tried it (or heard of it being tried) with Japanese beetles, and also Japanese beetles like almost EVERYTHING. It's hard to tell what they'll go to and what they'll avoid. I've had them eat my marigolds but leave my rose bush alone (I know; WTH??), and I've had them do the opposite. :/ I'll do some research and get back to you on that one . . . . .

If you don't have a whole lot of basil plants (or feel like putting in a ton of effort), you could do tall row-covers-on-sticks. Make certain you've removed all beetles first, or they'll just happily munch away under the row covers. Bear in mind that this would not be a good first line of defense in the spring, though, since they hatch from grubs underground and come up wherever they please.

Okay, did a little research on trap crops. The internet says: African marigolds (they're the tall, skinny ones), borage (although, the poor borage!), evening primrose, and knotweed (I don't know if they mean the little pink-and-white flower that most gardeners refer to as knotweed, or the big-ass fuzzy plant that farmers tend to call by the same name. I would not advise intentionally introducing either . . . .).

The internet also informs me that interplanting with four o'clocks can a) attract and b) poison the beetles. I'm beginning to suspect that the internet is full of shit.

So, yeah. Sorry to be the bearer of bad news! A few last bits of info that may prove useful:
1. For long-term control, DO NOT use those yellow pheromone traps. They just attract extra bugs.
2. For long-term control, DO use milky spore. It kills the grubs. May take several years. If you have close neighbors with tasty plants and un-milky-spored lawns, the adults will probably wander in, though not in as great numbers as otherwise.
3. When hand-picking, go in early morning or late evening, when they're less active. Hold your container full of soapy water below the leaf or branch you're picking from, as a few bugs will almost always try the "drop off the leaf and you can't find me, ha ha" escape tactic.

Hope any of that helps!! The next time I have access to a) Japanese beetles and b) four o'clocks, I will monitor that and confirm/deny, and will also test out some trap crops. Until then, happy hand-picking!