Any problem with contamination when fermenting in a greenhouse?

Hey all,  question for you...

My fermentation experience has mostly been in a conventional house in Wisconsin year-round.  Now I live outside off grid in the high desert of New Mexico.
 
There was no possibility of fermenting anything this winter (we slept with wool hats, cooked in winter outdoor gear, and didn't shower).

Now the weather is warming up and we have also built a greenhouse, so we have some decent temperatures and are ready to start fermentation again...

The greenhouse temps are a bit warmer than the rest of our camp... swings from mid-50s- high 80s rather than 30s-80s.  So it seems like the best place to ferment.  

It is a pit greenhouse; lots of dirt and lots of manure.  Is there any greater concern about "off" microcritters invading our ferments in this type of environment?

Thanks in advance for any insights!

Kimi

I'm much more worried about the higher temperatures in the greenhouse than I am about the microbes. My experience is that warmer temperatures tend to encourage less favorable microbes.