Auxin Posted February 27, 2007 (edited) I've read repeatedly that Trichocereus pachanoi is hardy to -10°C, but just how hardy is it to that temp? Like how long could it be below freezing? 12 hours a day? more? Or is the "hardy" just like 'woops, I carried it through a cold room'. Based on the -10° claim they could stay outside most the winter in usda zone 7a (I think theres one mountain range in australia that cold ) I was never willing to risk the experiment before but last year I split my largest (all be it fairly small diameter) cactus into 4 cacti and right now theres 1 month til spring and ~2 months til last frost and the nights are between -3 and +3°C with an anticipated lower extreme of -5° before summer starts. But it could still be below freezing for like 12 hrs/day on some days, whatcha think? My cacti always suffered from too little ferts and no winter dormancy, the former I fixed, for the latter I was better about clustering them in cold spots this year but I'm not sure any went all that dormant. Edited February 27, 2007 by Auxin Share this post Link to post Share on other sites
Auxin Posted February 27, 2007 Found a interesting thread on e-dot indicating that cold hardiness is inversely proportional to amount of water the plants receive with watered plants doing poorly at -2°C (starting with tip burn and getting worse from there) and the most water starved cacti doing fine even below -10°C. It makes sense really, the more concentrated antifreeze is the lower temps it can handle and if a cactus is thirsty the 'antifreeze' in it is more concentrated, even at the tip. Its been 13 days since I watered last so I'm thinking I might try it and just not water til a warm stretch in the middle of next month at the earliest. Share this post Link to post Share on other sites
apothecary Posted March 1, 2007 The two pieces of info I know in this regard are reports from Rev. One is that the cacti can handle extremely cold temps as long as the days are warm enough, and two, like you said dormancy is one of the main factors in winter survival. Share this post Link to post Share on other sites
kakti Posted March 1, 2007 All of my cacti except my T. Terscheckii died this winter from cold. They experienced daytime temp's in the mid 20's F, and possibly a little colder at night. They hadn't been watered in 4-5 months, and were all well established. Seriously, don't take the risk Share this post Link to post Share on other sites
Auxin Posted March 1, 2007 Ouch, sorry for your loss. Zone 5 is clearly too cold Zone 5b gets down to -23 to -25° C (-10 to -15°F), I'm fortunate that my area gets down to -11°C at the most. Last night I left a little log with a baby pup out to be exposed to three or so hours of -1°C weather no tissue damage evident today so I'll leave it out again tonight (expected -2°C). I'll use that little guy to forge new ground but even so I think next year I'll bring everything indoors for the coldest several weeks so none except possibly the test cactus are exposed to temps below -7°C (19°F) and I think the largest few will stay inside half the winter. If I loose some cacti it'd suck but it would also tell me just how far I can go and light a fire under my ass to buy new fatter cacti Share this post Link to post Share on other sites
gtarman Posted December 23, 2013 I'm fortunate that my area gets down to -11°C at the most. Last night I left a little log with a baby pup out to be exposed to three or so hours of -1°C weather no tissue damage evident today so I'll leave it out again tonight (expected -2°C). I first read that as "last night I left a little dog with a baby pup out to be exposed". I had to revive this thread just to say what a heartless bastard I temporarily thought you were lol Share this post Link to post Share on other sites
