We're in zone 6, and usually let ours grow until other cool season crops are gone. It lasts all summer and into the fall for us, and I believe it is less bitter after a light frost...it will survive cooler weather very well, and only be killed by a hard freeze. You might find you could keep yours going for well into the winter, especially with the help of a bit of mulch, if it survives your zone 8 summer. I think it is a biennial, so if it is still alive for you next year, it will probably go to seed.

The best way to harvest it is to cut off the outer stalks, leaving the central ones to keep producing. We usually wait until the stalks are about an inch wide, but it can be eaten at any size you wish; it doesn't seem to "toughen" as much as many other vegetables as it ages.

The most basic way to cook it is to boil it as you would spinach. I usually cut the stalk part in bite-sized pieces and the leaves as I would for spinach. I don't like it partially cooked; cooking it well seems to modulate the flavor. I usually let it boil about twenty minutes, then probe a stalk with a fork to see if it is soft. If it is, then I eat one piece to see if it still has any crunch at all in it. If it does, I cook it longer, but you have to decide how you like it. I would never eat it raw. I suspect it may have chemicals in it, similar to New Zealand spinach, which are best cooked away.

My DH likes it with vinegar, and I prefer it topped with butter or cheese (for cheese, just place the drained chard in a serving bowl, top the cooked chard with the cheese of your choice, and warm in microwave for a minute. I like to use cheddar).

Recipe Source has a few recipes that use it, but I've never tried any of them. I used the stems once, cut long, as a substitute for lasagnia noodles (zucchini cut lengthwise could be used the same way).

Swiss chard is a vegetable that really cries out for the attentions of a skilled chef. It has a slightly bitter, bland taste that needs complementation in the same way that eggplant and zucchini do. I suspect that long stir frying with onions and garlic would make it much more interesting; if done with fairly young leaves and stalks that might be a good way to have it.

I never had Swiss chard before meeting my DH. He grew up in the Midwest, and his family did a lot of canning. One year their Swiss chard was the only crop to survive, so all that winter, that is what they ate. Needless to say, it was years before he became interested in it again...it's one of those vegetables you can usually depend upon, though, in a pinch.

Here is a link that might be useful: Recipe Source ideas

It can be picked whenever the leaves are the size you need. My favorite simple preparation is to chop it up (I separate the stalks and leaves so that I can cook the stalks longer) and saute it in olive oil with some minced garlic. You can then throw on some nice vinegar of your choice and some sea salt and let it sweat for the last minute or so of cooking. The vinegar balances out the bitterness of the veg.

You can also use it in soups much the way you'd use kale, but you might not want to use the stalks in that instance.

Try this sauteed chard. I know you will like it.

http://www.harvestwizard.com/2008/06/sauteed_chard.html

It's great with grilled salmon or chicken.

Here is a link that might be useful: http://HarvestToTable.com

Thanks so much for the wonderful info and ideas! Can't wait to try my swiss chard!

We like it raw too! Harvest when leaves are less than 6" long. I mix it with other greens in a salad.
I've used large leaves in place of cabbage for cabbage rolls. Stuff with a meat/rice/veggie mix, put in crockpot and pour tomato sauce over them and let cook!
Sauteed with butter and garlic. Boiled and pureed, cooled for an ingredient in dip (think Spinach Dip). Blanch, chop and freeze for winter use. Leaves and stems chopped in soups. Yep! Chard is always dependable here in Z8, Willamette Valley, Oregon! It winters over!

Deanna

I disagree about cooking chard that long, but personal taste is personal taste, after all. Young chard is great in salads, too.
I like to wilt mine (barely cook it at all), and dress with olive oil and minced garlic (sometimes lemon juice or vinegar, as I would spinach). I also like it chopped up in spaghetti sauces, in lasagna (chopped fine and mixed with the ricotta), ay way I can get it, really :D

I disagree about cooking chard that long, but personal taste is personal taste, after all. Young chard is great in salads, too.
I like to wilt mine (barely cook it at all), and dress with olive oil and minced garlic (sometimes lemon juice or vinegar, as I would spinach). I also like it chopped up in spaghetti sauces, in lasagna (chopped fine and mixed with the ricotta), ay way I can get it, really :D

When to harvest, How to prepare it, do not have unique answers. You can pick them when the outer leaves are 4- 5 inhes, or let thm grow as big as they can get. Eating them is the same way; In salads, steam, saute, use in stir fry.
I like them the way chines use bok choy, in stir fries and barely steamed or boiled to have the crunch an color.