It will be toast. Covering as with tomatoes may delay the inevitable for a while, though.

To avoid this, pull the plants just before frost and take inside to dry, then harvest the leaves, flowers, and fine stems to use over the winter.

I can tell you that YES, they will be toast, I had a HUGE beautiful plant last year, so big you could not wrap your arms around it (I had to try to stake it up becuase it was so big it was falling over). I had every intention of preserving the leaves since I absolutely love to cook with basil.

I somehow was not paying attention to the weather like I usually do, and we got a sneaky frost one night. It literally only was cold for a few hours, but the frost was what got it. Since I did not cover it, literally the next day, it was BLACK and dead. I was heartbroken.

This year, I have planted more plants and I'm on top of the weather. I wont probably try to cover them, I'll just harvest them in time.

Yep, it'll be a goner. This year I planted my basil in a big clay pot so I could move it inside on chilly nights. It's a pain - literally - to move, but so worth it.

I've already harvested three times. Made some pesto, of course, but I also like to pop it in the food processor with a little olive oil. Then I put in in a baking dish lined with plastic wrap and pop it in the freezer to flash freeze. Once it's frozen I break it up into chunks and keep it in a freezer bag - wonderful on roasted potatoes and available even after I lose the plant to frost!

Agree with the others, yes, basil will bite the dust. But, the good news is it is still possible to grow some in a pot for indoors. I do that every year. I think you still have time in zone 6. Basil seeds germinate fast in warm soil. Put a few in a pot and take it indoors when the weather turns cooler (before the frost) :) I use an 8 inch pot, deep one, because they really have a root system. Water every day during the winter and you will be rewarded. I usually keep mine going all winter long in a south window. Love the stuff.

Ever make tomato confit? Put whole tomatoes, whole garlic heads, sea salt, pepper, and a ton of basil leaves in a big wide baking pan. Pour olive oil over all and roast uncovered in a slow oven for several hours. When the tomato skins come off, just pick them out. The garlic will just pop right out of the head, soft and yummy. You can freeze it if you like. It is so good on pasta, or used as a dip for garlic bread. Yum!

Basil is the first to die. Even a hint of frost....
One option is to harvest all the basil, make pesto and freeze it.

As you have guessed from the previous posts, a touch of frost is lethal to basil. Even here in Texas I usually lose my basil plants in November when we get a frost. However, basil roots easily, so take cuttings of new growth now, and put them in sterile soil under a plastic cap, or root them in water. Then plant in an indoor pot and enjoy a small but oh-so-important harvest of fresh basil until next spring. Seeds will grow also, but the cuttings give you a head start.
Isn't the recipe for tomato confit mouth-watering?

It is true that basil will die but you can simply strip it and burn down your house mwah haha ha ha