The large pot should be large enough for one mature basil plant, at a pinch.

Catnip grows to 1 metre high with a spread of about 40cm and has has a somewhat straggly growth habit. That's ONE plant.

A mature parsley makes a nice armful - if it's Italian parsley, it might just squeeze into your oven.

In brief - when it comes to herbs - think about 3-4 times the size you expect! And pots to match. As a rough rule of thumb, the bit you see above-ground is about the same size as the bit you don't see underground - image the plant in the pot upside-down in the pot. Visit a nursery to see some mature plants and choose your pots accordingly.

Another consideration is the needs of individual plants. A mixture does not generally do too well - some need rich, moist soil, others need dry conditions etc. And one plant will usually out-compete the others. Think of a mixed-pot as a garden-bed, and it's easier to visualise. You need to do some homework - plenty of info in this forum if you use the Search facility.

In actuality, the root system of a plant does not mirror the above-ground part, but exceeds it greatly in size. This is true even with herbaceous plants and annuals. Plants grown in containers are already subject to constrictions, and won't thrive in such tight quarters with a bunch of cell mates.

All the more reason for you to do a bit of research on the expected sizes of all of these plants.

Putting various herbs together is a very common query in this forum. Searching back posts is a very good suggestion. There is reams of data!

If you look at the bottom of the top page for the Herbs forum, you will find the search bar. I find the GW search bar so-so and often use google to search the forum. You can use the google "advanced search" options by clicking that light blue "Advanced Search" under the main google search bar and setting the site/domain to be http://forums.gardenweb.com/forums/herbs/ plus then setting the other search options as you wish. You'll get all sorts of results from this forum matching your query.

Use both searches. You'll probably get different results but see what meets your needs.

FataMorgana

My cutting pasting leaves something to be desired to day! Set site/domain to be forums.gardenweb.com/forums/herbs or forums.gardenweb.com/forums/load/herbs - leave off the "http://";

FataMorgana

I agree with Daisy. But it is a common pracrice to make
mixed herbs pots. I see them often at big box stores. They mix things like parsley, chives and basil. I can tell that they may not last even one season. But if someone likes to do it, can be done. But choose a much bigger pot and be prepared to water it, sometimes twice a day.
BUT(a big one) YOU CANNOT DIRECT SOW THEM IN THE SAME CONTAINER/POT. Normally they are transplanted seedlings grown separately.

I did some research. ... whew I didn't realize these plants got so big! Thanks for the help!

I have done it with great success. Sure, the plants get NO where near the size they should get...but to have a 1-pot mixture of herbs right in my kitchen window to grab a few leaves of this and that is priceless to me. I grow additional basil in my main garden to use the volumes for pesto and such, but the convience of my herb bucket in my kitchen is too nice to give up :) My herb bucket usually contains basil (3 plants), rosemary, thyme, oregano and parsley. Last year it was a 12" pot and I crammed all these transplants in there. This year I am moving up to an 18"x18" horse trough type thing and will plant it similarily, probably with the addition of cilantro.

Like I said, I have basil and sage also in my garden for larger quantities (drying and pesto) but I do love the convience of my little herb bucket. I didn't see any one plant suffer, but the oregano sure loved to be there!! They stay tiny and compact in this pot, but for the few times I week I plucked from it, it held up real well. I even had parsley all winter long after the other plants died off!

Makes a pretty centerpiece on my kitchen table too :)