I have Wooley Thyme between stepping stones. I've only bought little plants, but I'd recommend buying Wooly Thyme seeds for your flagstone.

Thanks. Any idea how much would need to be bought?

Calculate it out figuring 20% germination rate and each plant covering four square inches. Are you planning to start these indoors? If not, how? Look at Dave's Garden web site for information on starting this from seed.

Awesome, thank you!

(Yes, I figured I figured I'd start them indoors and then re-plant in a month)

For each 4" x 16" area I'd plant 3 plants. That will give fast coverage. Not sure how many seeds.

Thanks a bunch you guys, great feedback all around. Last question is: the sidewalk looks pretty weird at the moment without the joints filled with anything. Could I just fill the joints now with Miracle Gro compost and then add the seeds a month from now once I've grown them indoors and transplant them? It looks pretty crappy right now with empty joints.

Is it autumn where you live? I wonder about weed seeds and fallen leaves getting into your joints and being a bother. Could you put down a roll of landscape fabric over the walk (plastic pins to hold it down) until the plants are ready?

That's a good idea. I was also going to add a layer of Preen to prevent weeds.

I would not use any kind of weed killer in the joints. Thyme is not a grass. The weed killer will kill the thyme.

Hmm, that makes sense, I was just going on what the lady at Lowe's told me, but I don't want to risk it.

I think Preen keeps anything from germinating.

Yes, Preen is an anti-germination agent.

Unless you have a greenhouse to start the plants, and providing that you live where tthe ground freezes, you might consider winter sowing your seeds--Google the term for instructions. Ive never done this, but ive heard it works very well.

I wish you luck. I installed the (basically) same type of flagstone walking path that you are building now. We found that the we really wanted to use the path or walkway more than we though and it became difficult to walk on, especially for guests and friends. Hopefully this will not be the case for you. I just tore it up and we are going to lay down herringbone brick in it's place. Best wishes.

If the thyme grows tall and you can't mow it short enough to keep from catching your toe or ankle on it, I suggest you look at www.purplestomes.com.

I have a photo of one of their projects in my IDEABOOKS, but could not figure out how to get it to attach here. The photo I saved uses small, flat river rocks, placed on edge, and pounded down between the flagstones in a design.

This is a good site (stepables) : suggests plants that can tolerate some foot traffic http://www.stepables.com/