Question
Hi guys - I have an outdoor bog approx. 10' x 3' x 24" deep in full sun just south of Pittsburgh, PA.  Soil mix is approx 2/3 peat:1/3 builders sand.  The bog was built in May 2008 and planted with a wide variety of Sarracenia.  

I don't have any negative symptoms in the plants, but a potential problem just occurred to me.  The bog is dug into a gentle slope, and the rear edge of the kidney shape has a sandstone retaining wall (native stone collected throughout my property) built *inside* my bog liner (2 layers of 8 mil plastic sheeting).  The finished soil level is approx. 6 inches above the the base of the sandstone retaining wall, such that aprox. 5-6 total square feet of sandstone wall area is below the soil line.  

My question is whether the mineral composition of the sandstone is likely to cause any ill effects to the plants by leaching into the bog soil.  Future plans include introduction of Dionaea and Drosera species, as well as various native bog orchids and companion plants.

Thanks for your help!

Answer
Hi Dustin,

From what I've seen, sandstone shouldn't be much of a problem.  Limestone would be a different matter.  As long as you don't have any concrete mortar areas that will leach in, it should be fine.  As long as you have good water flow, what little mineral that might be there would run out.  Also, large containers such as bog gardens tend to have fewer problems with this anyway.

Good Growing!

Jeff Dallas
Sarracenia Northwest
http://www.cobraplant.com