# Crypt cold hardiness



## rs79 (Dec 7, 2004)

You know, for a tropical plant these things really are cold hardy. I was away from home for 3 months in the depts of winter here and winter here can hit -44 (at which point F and C are the same). My dad was supposed to keep an eye on things and tried to save me money by turning the heat down a bit. The water in my tanks was a few degrees above freezing when I got back.

Every fish died. No snail did. Every crypt except balansae dropped all its leaves and looked dead. "blassii" and pontiderifolia seem to have vanished but several forms of x willissi, undulata (?) "lucens", petchii, all sprang back. I have a couple now putting up leaves again that I don't remember what thay are.

Any expensive stem plamt croaked. All the cheap ones survived. Java fern, java moss, crinum and anubias didn't seem to even notice. Tropical lilies croaked and I"m hoping may come back.

A few years ago I had some C. albida in emerse culture outside (I can't grow them submersed but they went nuts in soil) that caught a ligth but killing frost. The leaves were all turned to much but once inside they came back just fine.

Just another data point...

Cheers,
Richard


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## HeyPK (Jan 23, 2004)

Jan Bastmeijer has made similar observations He reported that some crypts he had growing emersed in a greenhouse survived overnight temperatures (in the greenhouse) below freezing.


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## rs79 (Dec 7, 2004)

Just an update - while all my crypts melted at near freezing temperatures (pontiderifolia, blassii, "grabowski" never to return), balansae didn't even drop a leaf. Interesting.


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## ruki (Jul 4, 2006)

This is useful info.

I keep a cold water tank for experimenting in the winter. I tried to keep it at 5 degrees C between December and March. My results were that many pond/tub plants wilt between 5 and 10 degrees C. Two plants did really well though. Giant duckweed and an emmersed Ranunculus species just slowed down. These plants worked as a filter for fish that can survive such temperatures. Chose not to use a filter or do water changes for this tank.

White cloud minnows did OK at this temperature. When it warmed up, lots of eggs produced. Now the adults are outside in a tub while the fry are still in the tank. The Least Killifish should also be OK, but haven't tried it yet.

Never would have guessed it possible that some crypt species might survive in such an environment.


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## Khamul1of9 (Oct 25, 2005)

Perhaps the temperature around the stolon was kept warmer??


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