Blackened Dahlia Depression

GardenGeisha

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How cold did you think it was going to get last night, DigitS'? What temp tends to do your dahlias in, even with the 55 degree F watering trick? It looks like some dahlias are hardy to 40 or 41, but I've always heard 38 degrees F is the bottom number? Are some varieties hardy to a lower temp?
 

digitS'

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Garden Geisha, I believe that plants toughen. "What doesn't kill you, makes you stronger." Well, not really. There are maiming experiences.

If a tomato plant is moved out of a heated, greenhouse environment into an unheated hoophouse and goes from overnight temperatures never below 60°f to 37° - it may die. I know as the result and my remote thermometer told me I had made a mistake a few years ago.

Outdoors on a still night, temperatures may vary quite a bit because of location of buildings and other plants. And, with a couple of weeks of chilly weather, the plants harden. I don't think that their tissue can survive freezing but that may not happen even if open air temperatures drop to freezing for a short while.

The Weather Service predicted a 33° morning at the nearest airport. A wunderground volunteer's thermometer about a half mile away showed that temperature briefly but the airport had a 36° low, also briefly. Yesterday, that airport was 34° and the volunteer's said 33°. Frost on all roofs and on the more open areas of the lawn, both mornings. ... yesterday, that situation went on for a couple of hours ... but the sprinklers were helpful.

Steve
 

GardenGeisha

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How do you get the water in the sprinkler to 55 F, Steve?
 

digitS'

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Oh no, GardenGeisha!

That's the temperature of my irrigation and house water.

At about 4' into the ground, the temperature is 55°f, year round.

Steve
 

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I see, Digits', thanks for the info. How cold is it to get there tonight? My buds are starting to unfurl, and it is supposed to be 37 here at 7 in the morning, so I'm going to need to cover my plants. Tuesday morning it is supposed to be only 36 degrees, and then it will be warm enough the following mornings, for a while. I don't like this time of year. Always so unpredictable. Generally our first frost is October 11-20, but it was earlier this year. Now, if I can just save these late buds!
 

digitS'

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The forecast for the nearest airport is for 37, also.

However, the WS "promised" no lower than 40 this morning and it was 35°f there!

Here at home, there was a little patchy frost on every roof. The neighbor complained about having to scrape her windshield. I will be out in the big veggie garden tomorrow ... it should be a bright, sunny day but it looks like garden clean-up time has arrived.

Steve
 

GardenGeisha

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Yep, it's mean ole Jack Frost time. I had such difficulty covering my dahlias this evening, due to high winds. I really had to fight them, but the plants are covered. I carried some tender ones inside, such as my potted Ground Cherries, which are truly delicious this year.
 

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Yep, DigitS'. Forecasters were wrong. It's currently 35 degrees here at 7:30 a.m. Two degrees colder than predicted! I'm glad I got everything covered last night. Brrr. Frost on the windshields.
 
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