Sage is a high light genus (in general), I suspect it's too wet and too dark for it.

yes, I think you may be right. :(

The plant in the supermarket had probably only been there a short time. It would have been brought from a greenhouse with perfect growing conditions.

Sage is another example of an outdoor herb which just doesn't want to be indoors. Apart from putting it into sub optimal conditions you have also put a severe stress on it by repotting at this time of year. It is a high light plant from places with seasons. To be honest I am surprised you have got rosemary and thyme to grow indoors.

All three are Mediterranean natives. They need a lot of light, not much water and cool temperatures during the winter. Until your lights arrive I'd put them into the brighest window you have and cross your fingers.

Regular potting soil is not a good match for sage either. It retains too much moisture and is too rich for sage. Sage would be happier in a loose, lean mix - something more similar to bonsai "soil."

FataMorgana

How about cactus soil?

Maybe but something that would be best for growing woody plants like trees and shrubs instead of succulents like cacti would be better. Sage is a woody, shrub-like plant after all and that is why I suggested a bonsai mix.

FataMorgana

Sage is a fairly large shrub... I can't imagine growing it indoors.

In the spring, buy a nice young plant at a nursery and plant it in your garden. Mine (in zone 6) stays green and usable all winter, so it will be very happy there with you in the Garden State. :-)

Common sage also is very easy to grow from seed but no one really needs more than one, or maybe two at most. But even with regular pruning common sage tends to become woody and less productive in a few years, so you'll want to start with a new one from time to time.

I much prefer Berggarten sage as it does not get woody in 2-3 years like common sage but has a nice mounding habit and does not bloom. You'll most likely have to look for a nursery that specializes in herbs in hopes of finding that cultivar, or else get it by mail-order.

Sage grows well and overwinters here in Western NY State as well. Everybody has their favorites -- and there is no right or wrong answer as to which is best. I've tried a number of culinary sage varieties including Berggarten but my favorite is the unnamed, standard garden sage (Salvia officinalis). I love the taste, blooms, and hardiness. Yes, it does eventually get woody but a large plant is more than enough for any kitchen for it pushes lots of leaves and new shoots if you keep it well pinched. I usually plant new young plants every 2-3 years to give them time to grow big and strong before the previous plant starts to grow weak. Sage is not a long-lived perennial. I usually expect at least 5 years out of them.

FataMorgana