Question
My patio is Montana slate about 8 yrs old.  I am trying to plant amongst the cracks and keep getting lots of moss.  We originally put the slate on sand and I have since filled in cracks with potting soil and am trying to get baby tears, sedum etc to grow but because I live in Seattle we have lots of rain and unattractive moss has taken over.  My question is what should I be filling the cracks with to encourage other low growing plants?  Should I go back to using sand? Thanks for any help!

Answer
Hello Claudia and Tom

Quite honestly, if plants like sedum and baby's tears are not growing in the cracks there is neither sufficient sunlight or sufficient shade to support the growth of these two plant species. Sedum requires hot sun and baby's tears requires a lot of shade. Therefore, I feel that there maybe another factor here that is preventing the establishment of these plants, maybe dry cold?

However, I would suggest trying a plant called Dichondra repens;
http://www.google.co.uk/images?hl=en&q=dichondra%20repens&um=1&ie=UTF-8&source=o... as this grows almost anywhere and will perform the same job as the other plants. Filling the cracks with a mix of loam, sand and peat respectively should work fine for all three plant varieties.

Thanks for any bonus points in advance.

Kind regards

Jonathan. www.ecologica.com