Question
I am a novice gardener, so I apologize in advance for my many silly questions.
I have a little over 500 square feet of parking strip at my house [I'm on a corner.] The parking strip used to be filled w/ grass and dandelions, but last summer I covered it w/ cardboard, compost and mulch and have been pretty successful in killing most of it off. [I hate grass and don't want to use any pesticides or chemicals.] I have just planted 4 street trees on one side and have another mature street tree on the other side. I am now planning on 'paving' much of the area w/ stepping stones [rustic basalt flats] spaced 4-5" apart and then planting creeping thyme in between the stones. I think I need to use seed, as I will go broke buying enough plants. One questions is: I am planning on scooping out much of the old dirt and replacing w/ clean dirt. But, can I place a layer of landscape fabric down first before I put the clean dirt back in? And then can I plant the seeds in the topsoil on top of the landscape fabric? I really don't want a spec of weeds or grass to come through.
Also, what would be the best method for planting the seeds? I have never planted anything before.
I live in Portland, Oregon and the parking strips have full sun [south and west exposures.]
So sorry for the length of this, but I want to do it right. Thanks in advance for any help you can give me.
-Lisa

Answer
Lisa, I would not put down landscape fabric.  I have found weeds and grass actually break right through the pores of the fabric.  Although it does help in cutting down weeds, it does not eliminate them.  The main problem you will have is that the fabric decomposed much too slowly and will therefore prevent the roots of the thyme from fully developing.

Instead, I would go ahead and replace the soil and then plant the seeds 3" apart.  The plants will spread and eventually cover the area.  Because it grows so densely, it will choke out competing weeds and grass, especially in year two.

One other alternative is to use newspaper to keep out the weeds.  Newspaper is a great barrier and eventually breaks down into organic carbon material.  Publishers are now using soy-based inks which means they are no longer toxic to your soil or plants.  Roots will still grow due to the quick decomposition of the paper.

By the way, I also try and not use chemicals in my lawn or gardens.  I have had good luck in keeping out weeds by using the square foot method of planting in my gardens, and overseeding every year in my lawn.  Intensive planting will shade out weeds causing them to die off.

Good luck, and please write again if I can ever be of assistance.

Regards,

Mike