Not sure how to help without knowing what size plastic packages you get. Here there are two or three different sizes, depending on the herb. And the answer would range from several to many. Really no place to buy bunches? These packages seem like an expensive option.

I know! I really don't want to run all over as I am crunched for time.

For pesto, eyeballing it is fine. (I’d use more then a Cup.) But here is a site that might help you.

The basil that comes in containers here are small and I would assume that they don't equal a cup.

The small clamshell herbs are usually greenhouse or hydroponic grown so way off season and expensive for pesto. Probably a 5th of a cup or less. Most markets have the tiny packets about the size of a bar of soap that are 2-3 dollars. Not much flavor in those packets.

You sort of have to visualize picking off the leaves and packing them into a cup measure. Most supplier sell with the stems for freshness but that adds weight. Woody stems have zero flavor and not usually used. The tender top of the plant stem is fine to use.

My market puts out crates of big leaf basil bunches in the Fall for about 2 months. A bunch is about 5 cups. That is when we make pesto with two bunches at 1.99 each. Then freeze in 1/2 pint containers for the winter months.

A cup of basil leaves is just barely enough to coat a lb of pasta. Just saying it could get pricy if you are buying off season.

Does your store sell herbs as plants? For the size that Publix sells around here, I would say all the leaves and leaf tips from a plant, but that's still going to be way cheaper than buying the packaged, even if you have to get rid of the rest of the plant.

Herb clamshells tend to come in different sizes ranging from .25, .75, 2, and 4 oz sizes. So it depends on what size clamshells as to how many you need to make a cup of packed basil. And don't forget part of the package weight is the basil stems you don't use so much, and sometimes some packages will seem to have more stem and less leaf than others. To help it fit and display nicely in the clamshell, I find that .75 or 2 oz basil is kind of skimpier on leaves than a 4 oz, but 4 oz isn't as common around here are the .75 or 2 oz shells.

I don't buy clamshell herbs, but I do note how expensive they are for what you get, lol. At this time of year depending on where you live, it can be cheaper just to hit the garden department and pick up a couple plants on sale and use them.

Too be honest , depending on what you want the pesto for, there are some really good prepared pestos available in good grocery stores.

The clam shell basil is tasteless in my view. I actually bought some fabulous jarred pesto from Costco two weeks ago.

"If you have a Trader Joes, they sell the whole plant for a few dollars ($2.99 maybe?)."

Yes, a good deal at $2.99. You can plant it and continue getting lots of basil.

If you buy the plant, watch out for ants (i.e., plant it outside, not in your kitchen).

So...I'd just take a cup measure to the store and ask the produce manager if he minds if I measure the volume of what's in the box. Just putting some leaves in, with the big stems sticking out, should help you eyeball the quantity. I'd think you might need a couple of the big clamshells they sell near me. I don't know what the weight is, and it depends on leaf to stem ratio more than package weight anyway.

Do you have any greens at home? Baby spinach or arugula leaves should be close enough in weight and texture to see how much your cup weighs. Or do half a cup and double.

I was just at TJ's. They have two different sized plants, as well as two sizes of clamshell. Eye balling the smaller plant, I think it had enough leaves to pack a cup. The larger one had way more than enough. The "one dish" clamshell isn't near enough. The large one should be more than plenty. Should be.

The cut basil at our TJ's comes in a plastic bag and if you used all of it it would be about two cups. If you doubled your recipes you could freeze whatever Pesto is left over. It freezes very well.

Don't forget, too, that you can piece out the basil with lots of other kinds of greens, like parsley or spinach and the basil will still give the pesto a good flavor.

I agree. Pesto is a very varied pleasure. You can use whatever you like, whatever is in season. An example is sage leaves and walnuts with the garlic, salt, oil....

I always think that food that is essentially food for ordinary folk doesn't need such precise recipes. We have always used what's a available.

It takes a LOT of basil to pack a cup full...a LOT! I would buy ready made pesto for this venture, then buy a couple of plants...or 3....and when they grow big you will have your own basil for pesto. I like a couple of kinds in a batch of pesto, but the red leaf gives it an odd color.

My pesto recipe (from the Moosewood cookbook) calls for 3 cups, packed. I have about 5 plants growing and they've gotten huge,. A colander full, before stems are stripped off, makes a generous 3 cups packed very firmly. I would guesstimate that a large double handful of leaves (maybe 2 cups?) would pack down to 1 cup.

FWIW, I grew this season's ginormous basil from seeds I saved from some Trader Joe's organic basil I stuck in water, and which rooted so vigorously and quickly, I decided to plant it in a pot. It grew quite large and healthy and I saved the seeds for this year. Seriously, the leaves are like 4" long and 3" wide, and the plants would be 3' tall if I didn't harvest whole branches.

Thanks everyone. I wound up buying 4 2.5oz boxes. Three would have been enough. So, now I know for the future if I like the way this comes out.

It calls for 12 oz of pasta, so not the full pound.