I'm sorry Kirk5a, I've scoured the web and I haven't found the original source. I remember the information being from an interview with someone from Suan Mokkh or from an article looking at the period between Ven. Buddhadasa's stroke and his death. I'll have a look again later.
Rain soddens what is covered up,
It does not sodden what is open.
Therefore uncover what is covered
That the rain will not sodden it. Ud 5.5