question about sealing planter boxes

[tommywalnuts]

I reclaimed some 1x6's from the scrap pile at work today. I am planning to make some hanging planter boxes to grow peepers in this summer. I wanted to seal the seams so water and dirt won't seep out(there will be drainage holes at the bottom). I was planning to use silicone caulk, but was wondering if there would be any adverse effects to the plants?

 

[sylvie]

Not certain about an exterior application but my brother has been making terrariums with the silicone caulk with great success. I think he has one that he's been using for 7 years, complete with some small critters like newts. Hasn't bothered the plants or animals.
ETA: I read your journal where you found the wood-great find!

 

[tommywalnuts]

LOL I was just sitting here looking at the aquarium thinking " they use silicone on that, and doesn't hurt the fish, so surely it wouldn't hurt plants. Appreciate it