Keep the basil separate from the thyme and salvia. For one it's an annual while the other two are evergreen perennials. And it appreciates a rich soil and lots of water......which the other two do not :-) I'd give them opposite sides of the bed with room in between!

As to how many to plant, how much do you use? Basil tends to get consumed at a much higher rate than thyme or sage so I would plant multiples of those but maybe only one or two of the perennial herbs. I tend to use thyme (and chives) more than any other herbs but one well-established plant is more than enough for a single person that likes to cook :-)

Thank you I would like for the perennials to come back but being in zone 7a I am not quite sure they would. Did not have much luck with my Rosemary which does not appear to have come back

Zone 7 should be fine for all of the perennial herbs. But they do require very sharp drainage, especially in winter. And not very rich soils.

Thyme and sage are hardier than rosemary. The death of the rosemary isn't a good indication of whether the other two will survive.

Saturn, you will have no problem with sage and thyme coming back. I'm on the border of zone 6 and 7, and they are very reliable. I have a raised bed with sage, English thyme, tarragon, lavender and Greek oregano, and so far so good. And the last few winters were brutal! However, I've never been able to keep rosemary alive, even with a lot of protection, windbreaks, covers during the worst weather, etc.

Like Gardengal said, you should keep basil separated from the rest. It requires more moisture and, even with constant harvesting, it will eventually flower, go to seed and decline before the summer is over.

If you are looking for more perennial herbs to add to your collection, I strongly recommend chives!

thanks I will consider that, herbs are something we use a lot in our cooking this will be the first time we have grown anything outside of Basil and Rosemary. Will just have to learn how to harvest the other two

Thyme is my favorite herb and I use it a lot! I just go out and snip off a few stems whenever I need some, strip the leaves off and chop lightly. Or sometimes I just include a whole sprig :-) Depends on what I'm cooking. Otherwise, I use chives, oregano and parsley a lot as well, rosemary now and again and sage hardly ever. Usually only when I cook turkey :-) And mint in summer.

I don't care for the taste of basil so I don't grow that.

I'm the same way with sage -- don't use it at all until Thanksgiving. But it makes such a decorative tiny shrub, and the flowers are also nice.

I use lots of sage, as I do lots of other herbs. Have you ever fried sage leaves and used as a garnish?