I built a little closet in the NW corner of my basement in which to store potatoes for the winter. It is vented to the outside, so there is high humidity, cool temps, and of course lots of mildew.
I insulated the top couple of feet of the foundation, put up wood studs and a vapor barrier, then green drywall. Never got around to painting it tho.
The drywall gave the mildew the food it needs, so along with the water and cool temps, it is fat and happy.
I am assuming the drywall has to go (I did wash it off with TSP & bleach), but what do I use instead? Or do I ignore it, since it is in a tight confined spot?
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The ideal conditions for a potato cellar are 38 to 40 degrees F and 90 to 95% relative humidity. I don't think mildew will grow at that temperature. If you can't keep the temperature below the range where mildew is active, I think you need to find a way to dry the closet out when it's warmer. That may preclude storing potatoes there during the warm parts of the year.
This site http://www.floridatoday.com/!NEWSROOM/columnstoryA12630A.htm says mildew can grow as low as 32F, but it's most active above 77F.
Edited to correct storage conditions and add URL. I was thinking of carrots at 32F and 100%.
Edited 10/8/2003 4:15:21 PM ET by Uncle Dunc
Maybe I'm confused. I've worked in several large potatoe storage cellars. Drying the potatoes out has always been the first concern (to prevent rot).
Perhaps I'm confusing surface wet w/ air humidity, as the cellars usually are cool and humid inside (they all have dirt floors). Though they aren't as cold as you suggest, nor would I think they approach 100% humidity. Well, 100% humidity at 32 degrees isn't very humid come to think of it.
I agree with you on condensation. Wetness on the potatoes or even on the walls, floor, bags, etc. would definitely be a bad thing. I corrected my brain f@rt on ideal temperature and humidity in message #2.
Ok, so humidity is good for potatoes, condensation is very bad. Still, if the first poster got rid of the exterior vent, ripped out the mildewed surfaces, them made sure his spuds were dry, he'd likely be ok. (A fan blowing acrost the surface of damp potatoes for a few days will dry the surface)
I'm in a dry climate, so a basement storage room will stay cool and dry if kept closed, may not be true down south or other places. A small AC unit would fix a problem of moisture condensing on the walls as well as cooling the room.
Also, it's better to store potatoes in a dark place. Exposure to light causes the surface of a potato to turn a green color and makes them taste bitter.
Have a friend who's done something similar.
His isn't vented to the outside (moisture is one of your biggest enemies when storing potatoes long-term.
His is a super insulated room (like 8" thick foam walls plus double opening doors that are both well sealed (one opening out and one into the room)). He deals w/ humidity by having a small AC window unit in the wall, a humidistat turns that on if humidity gets to high, a thermostat if it gets to warm. A small space heater on a freeze plug keeps the room from getting too cold. Since the room is so well insulated they seldom run.
As far as mildew, I'd rip it out and get rid of it. Not something I'd want anywhere in my house.
Somehow you've got to deal with the humidity. High humidity will lead to potatoes rotting, as well as the mildew.
Thanks for the ideas folks. I think I'll rip out the drywall (which must be the food the mildew needs), and see what happens with just the plastic vaper barrior in place.
It may be that the mildew will only grow during the summer, so I should open the closet up after the potatoes are used up, close off the vents, and see how it goes.
Thanks again,
Howard