Squash vine borers were our archnemesis during our early years on the farm, so much so that I even resorted to spraying Bt on the plants' stems.  And I'm glad to say that the Bt didn't help.  Why am I glad?  Because if that seemingly innocuous* spray had proven effective, I might not have figured out less intrusive ways to keep vine borers in check.

Variety selection was part of my solution, as I'll explain in a later post, but the biggest reason I started being able to harvest summer squash is because I learned to succession plant these speedy vegetables biweekly in the summer garden.  Here in zone 6 (last frost: May 15, first frost: October 10), I plant crookneck (summer) squash on May 1 (a gamble), May 15, June 1, June 15, and July 1 (a slight gamble), a schedule that allows us to be overwhelmed with tasty squashes despite heavy vine-borer pressure and with the use of no other control measures beyond variety selection.

Yes, the vine borers move in and kill the squash plants eventually, but not until after I've collected at least one big harvest from each bed.  By the time the earliest vines start ailing, I have another planting of summer squash just waiting to take their place.  Those of you living further north can simplify this campaign further since your vine borers generally only go through one generation per year instead of two, so if you wait out the borers, your late plantings of squash should be pristine.

Succession planting is handy with other types of vegetables as well, although the strategy only works if you choose varieties that put out a big harvest right away.  For example, I succession plant bush beans rather than growing runner beans since the former provide lots of green beans before the bean beetles move in to dine.  On the other hand, succession planting wouldn't be a good choice for tomatoes since even determinate varieties require months of growth before they ripen their first fruit.

Another benefit of succession planting comes when the food reaches our table.  A few studies have suggested that cucurbits (and perhaps other vegetables) have more micronutrients on hand when they mature their first fruits, so the earliest harvest often tastes best.  Some gourmet farmers pull out their squash vines after the first harvest as a matter of course, figuring it's better to maximize flavor rather than yield.  So maybe the borers are trying to do me a favor by prompting me to eat the most nutrient-rich and tasty vegetables possible?

I hope you enjoyed this excerpt from Naturally Bug-Free!  If so, you can download the ebook for $1.99 on Amazon by clicking the link above.  Or just wait for another excerpt tomorrow on the blog.

* The glossary of Naturally Bug-Free suggests some ways in which Bt might not be as safe as many of us think.