Author Topic: cold tolerance in FL vs. CA  (Read 1838 times)

joehewitt

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cold tolerance in FL vs. CA
« on: April 12, 2017, 07:18:01 PM »
I am reflecting on the nature of cold tolerance and hardiness zones as I survey the winter damage to my plants, both outdoors and in my unheated greenhouse. I gambled heavily last year and collected tons of stuff that I thought MIGHT survive here based on accounts read on this and other forums. As I was mourning the loss of my Seashore Mangosteens and Achachairu that were in the greenhouse, it really hit home just how worthless hardiness zones are.

If I read on this forum that someone in Florida zone 9b had success with a plant, I felt it was worth trying, because I am in zone 9b in California. That has turned out to be TOTALLY WRONG. My message to future California zone pushers reading this: ignore every bit advice you get from Florida growers.

It really doesn't matter how cold it gets - it matters how cold it stays. Correct me if I'm wrong, but my perception is that if it gets down to 28F in Florida it might stay that low for 30 minutes, while in California it could hold for hours. The Florida humidity makes the effective temperature much higher, and that afternoon you're back into shorts and a t-shirt. In California after a frost when it "warms up" you are still going to want a sweater. So, injured plants in Florida get the warm conditions to promote healing almost immediately, but in California the ambulance won't arrive for months.

Someone should really develop a model for plant hardiness that accounts for humidity and total chill hours in addition to absolute lows.




« Last Edit: April 12, 2017, 07:22:22 PM by joehewitt »

ScottR

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Re: cold tolerance in FL vs. CA
« Reply #1 on: April 12, 2017, 07:27:14 PM »
I totally agree Joe, I noticed that awhile back about Caif.& Florida  also noticed in Arizona how they can lose citrus to the ground one year and before year is over that tree has bounced back because of heat they have. All zones are not the same to many variables!

CGameProgrammer

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Re: cold tolerance in FL vs. CA
« Reply #2 on: April 12, 2017, 08:37:58 PM »
The only thing to keep in mind is average vs extreme temperatures. For example Tampa is considered zone 9B but it's from what I've seen it's usually 80 degrees every day in the middle of winter, with the low being 50+. But they have had record lows of well below freezing. On the other hand San Diego is typically in the 50s or low 60s in winter, with the low being around 35-40 degrees on the coldest nights, but the all-time record low is only 28 and really I have never seen it go below 35 in my 12 years living here. And it's considered zone 10B even though it's much colder than Tampa generally, as well as drier.

But I too like to experiment. My Ross Sapote is doing well, wax jambus thrive, green sapote is really growing well though no fruit yet (too young), caimito survives the winter easily but hasn't flowered yet... you never know until you try.

JF

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Re: cold tolerance in FL vs. CA
« Reply #3 on: April 12, 2017, 10:54:25 PM »
Palm Springs where our friend Gary lives is 9B but can you compare that with 9B in northern California? absolutely not. We've discuss this at length with a poster from Northern California that argued in his special micro-climate, 10A/B zone,  he could grow mangosteen,theobroma,santol all tropicals under the sun as long as he grew it in a GH for a few years and planted it out......he was laugh out of this forum, to be more precisely ban.