Tuesday, July 8, 2008

Homemade Non-toxic Bug Spray

Reality Sandwich recently posted an article on permaculture, addressing ways of combating insect damage in the garden. While the principle of encouraging greater diversity in the garden as a means of controlling insect pests is great, sometimes I'm just not willing to sit back and watch a crop of plants I grew from tiny seeds be devoured by anyone else but me. I'm not giving up this year's kale crop while I wait for the beneficial predator insects to notice the abundance of prey in my garden.

My favorite vegetable right now is kale lacinato, also known as dinosaur kale and by a bunch of other names. It's delicious to me, and to a number of hungry insects as well. Fortunately, it's a sturdy plant and it stands up very well to a fairly potent insect repellent that's easy to brew up at home. I promised a while ago to share my recipe for this effective, cheap, and non-toxic pesticide. So here it is.

To make this spray you'll need the following: a large mixing bowl, three large cloves of garlic, a teaspoon of chili pepper flakes, and a bar of glycerin soap. You'll also need a clean spray bottle for application.

Place the bowl in your kitchen sink and turn on the tap. Wash your hands with the bar of glycerin soap and rinse them off, letting all the water and soap suds collect in the bowl. Next, peel and crush the garlic cloves, so that they are well broken and flattened. Put the garlic in the soapy water and add the chili pepper flakes. If the bowl is not full, add more water so that there is at least 2 to 3 quarts of liquid. Let this steep for 24 hours and then strain it into the spray bottle. If you have more than will fit in the bottle, label and refrigerate the mix. It will keep for several weeks.

This spray can be applied liberally to kale lacinato, and should be re-applied approximately every 10 days as new leaves continuously form. I apply it to the heart of the plant, where the new leaves form, and also to the undersides of the larger leaves, where most insects seem to like to hang out. I also try to reapply the spray after heavy rains. I have also successfully used it on savoy cabbage, which seems not to mind the spray either. DO NOT apply this spray to Swiss chard. Chard apparently has a more delicate constitution, and it will literally curl up and die in response to this spray. I still see a slight amount of insect damage to the kale and cabbage, even when using this spray regularly. But it's a level of damage I can live with. I still get to eat most of the leaves.

I usually prepare the kale by rinsing it well and then blanching and shocking it in ice water, before going on to sauté it. It might be a slightly laborious cooking process, but it serves a few purposes. Firstly, it washes off any trace of the soap from the spray. Secondly, it washes off and/or kills any small bugs or caterpillars on the leaves. (And yes, there always are a few in each bunch.) And thirdly, it makes the leaves very tender and able to absorb flavor better than if the leaves were sautéed directly from the raw state. It also freezes beautifully after blanching and shocking. I put up most of the kale I grow for consumption during the winter months. I eat more chard during the summer.

Got any homemade gardening solutions to share? Let me know.


Tracy said...

Sounds similar to a concoction my grandmother used to make to spray the fruit trees to discourage insects. :) I'm going to write this down and perhaps try it next year!

Kate said...

Thanks for the note, Tracy. I hope this works well for you. I enjoyed visiting your site.


Carl said...

We don't use glycerin or garlic, but we have a bush producing loads of extremely potent chillies (shaped like capsicums, but plum-sized). We just run 10-15 of them through a food processor with a cup or two of water and spray that. After only two applications, we have far less aphids on our chives!

This might not have worked so well if the chillies weren't so hot that just the odor of the spray is enough to make you gag, like ammonia.

By the way, don't let chilli spray touch broken or irritated skin, or you'll know about it for hours.