Recent Frosts - any damage?

[mark smyth]

Today is the first I have got in to my green house since the hard frost arrived. When the frost came earlier this week it was colder than expected and too late to put fleece on plants. A couple of days later we had a quick thaw followed by another hard frost and snow. The doors of the green house have been stuck closed. This morning I went out to look at the damage to plants.

Crocus - buds OK but open flowers wilted
Nerine sarniensis - many leaves wilted and some badly frosted
Pelargoniums - frost damage as expected
Hypoxis hirsuta - all leaves badly frosted
all non hardy plants dead
Terracotta pots broken

The last time I had plants die was new years eve 1999/2000

[Michael J Campbell]

Mark,would you not put a little fan heater in the greenhouse set at 0c to keep the frost out, it would be cheaper than the cost of replacing the the plants you have lost.?

[mark smyth]

I actually have heated plunges but didnt think I could turn the heat on when the pot contents were frozen

My Daphne bought as Jacqueline Postill but possible Gurkha was almost in fill bloom prior to the frost. All the flowers are now brown.

[johnw]

Today is the first I have got in to my green house since the hard frost arrived. When the frost came earlier this week it was colder than expected and too late to put fleece on plants. A couple of days later we had a quick thaw followed by another hard frost and snow. The doors of the green house have been stuck closed. This morning I went out to look at the damage to plants.

Crocus - buds OK but open flowers wilted
Nerine sarniensis - many leaves wilted and some badly frosted
Pelargoniums - frost damage as expected
Hypoxis hirsuta - all leaves badly frosted
all non hardy plants dead
Terracotta pots broken

The last time I had plants die was new years eve 1999/2000

Mark - How awful.   Did your heating fail or was the heater just not up to the task?

I can help you out with Nerines but you had so many irreplaceable ones.

johnw

[mark smyth]

It wasnt turned on  because I thought plants would thaw too quickly

[johnw]

Mark - I have a propane furnace. My fear is that some day it will fail so I had an electrical company make a gadget for me. It is a huge heavy duty plug that is connected to a thermostat which in turn is connected to two plugins.  I have plugged a small ceramic heater into it with the thermo set at +3c and the heater set on full blast; the propane furnace thermo is set at 4c.  It cost $175 for the gadget.

My alarm company says they can install a remote sensor for 1c just in case there is a total failure. Cost $150. If it trips they will call us on our cell phones.  

BTW - This gadget was needed as cheap ceramic and other electrical heaters have no temperature settings, they have high to low.

johnw

[mark smyth]

I was caught out by the first hard freeze and it's been a long time since N Ireland has had so much snow. I see on the weather forecast more his due mid week

[Michael J Campbell]

Mark,I would have been delighted with some snow cover, we never go as much as one flake of snow while the rest of the country was under a thick blanket. Lots of plants in the garden very black and dead looking.

[Sinchets]

I found out that Scilla aristides doesn't like -9C on the leaves, but the flowerbuds still look fine. Scilla messeniaca in the garden looked like boiled cabbage, but seems to have recovered now.

[jomowi]

Cannot tell you about frost damage, haven't seen the garden since the snow fell and still no thaw.  Imagine, vain hope' that the snow will protect many plants.

Brian Wilson

[angie]

Mark sorry to hear about your plants.
I left out some mature alpine plants in terracotta next to my greenhouse I hadn't noticed but water had been dripping from the gutter onto the pots and they were raised out of there pots about a inch and they have another inch of frost on top of them I have removed them and put them into my polytunnel to defrost I do hope I haven't killed them.
I cant remember seeing so much ice on the ground like we have here.
Roll on spring.
Angie

[Paul T]

John,

You can get similar "plug in" type instruments that activate a standard powerpoint when it gets to a certain temperature.  I have one here that I used to have in an old glasshouse.  It plugged into a normal wall plus socket, turning it into a temperature control.  If the temp got above 30'C (which was what I set it to) the power would come through it and the fan would turn on..... otherwise the power was off.  It is a small control box that sits on any power point, with a metal cord and sensor that can be placed up to 2m from the powerpoint itself.  No installation needed, just plugged straight in.  These should be available elsewhere I would imagine.  When my sister sold that place I unplugged it and brought it with me in case I ever need it again, and I am thinking of running an extension cord out to my covered shadehouse just to be able to install this fan to try and cool it down a bit in summer.  So simple and easy and moveable anywhere it is needed.

Does everyone understand my explanation of how it works?  If not, I'll try to explain it further.

I'm only mentioning this so if others are thinking of something like this they can look around and see whether they are available.  I would imagine that there are minimum temperature versions of this as well, instead of maximum temperature like mine.  I bought mine from a hydroponics shop as that was where I came across it.  I would imagine that larger or specialist hardware stores overseas might standardly stock them, but ours here don't have as wide a range of things for glasshouses etc.

[johnw]

John,

You can get similar "plug in" type instruments that activate a standard powerpoint when it gets to a certain temperature.  I have one here that I used to have in an old glasshouse.  It plugged into a normal wall plus socket, turning it into a temperature control.  If the temp got above 30'C (which was what I set it to) the power would come through it and the fan would turn on..... otherwise the power was off.  It is a small control box that sits on any power point, with a metal cord and sensor that can be placed up to 2m from the powerpoint itself.  No installation needed, just plugged straight in.  These should be available elsewhere I would imagine.  When my sister sold that place I unplugged it and brought it with me in case I ever need it again, and I am thinking of running an extension cord out to my covered shadehouse just to be able to install this fan to try and cool it down a bit in summer.  So simple and easy and moveable anywhere it is needed.

Does everyone understand my explanation of how it works?  If not, I'll try to explain it further.

I'm only mentioning this so if others are thinking of something like this they can look around and see whether they are available.  I would imagine that there are minimum temperature versions of this as well, instead of maximum temperature like mine.  I bought mine from a hydroponics shop as that was where I came across it.  I would imagine that larger or specialist hardware stores overseas might standardly stock them, but ours here don't have as wide a range of things for glasshouses etc.

Paul - They are available here but none are capable of going much below 10c it seems.  The one I had made can also be used to turn fans on at 20c or higher.

I had the same problem finding a thermostat for the propane furnace when it was installed. I finally found a Honeywell that goes as low as 5c, the others stopped at 10c.  In those days the digital ones I was told didn't handle humidity well.   

johnw

[cohan]

Paul - They are available here but none are capable of going much below 10c it seems.  The one I had made can also be used to turn fans on at 20c or higher.
I had the same problem finding a thermostat for the propane furnace when it was installed. I finally found a Honeywell that goes as low as 5c, the others stopped at 10c.  In those days the digital ones I was told didn't handle humidity well.   
johnw

i've thought of the idea of a greenhouse heated only when its below -10C or even -20C..i can just imagine the looks i'd get looking for a thermostat for that...lol
i guess i'd just have to have a small heater that i turn on when its really cold...lol

[Paul T]

John,

Fair enough too.  I have only had experience with the heat sensors, not cold sensors.  I used to have an oil column heater (but it was a single flat pane, rather than a bunch of parallel slats) that kept my old glasshouse above freezing (mostly).  Not quite having to cope with the same sort of cold as yours would be, but then again my glasshouse thing wasn't terribly well insulated either.  

Yours is far more precise, which makes sense to go the made to order route.  My battle is keeping the covered house from getting too far over 40'C, or nearly 40'C in winter (Yes, it has been very warm in winter, even with the door open etc..... we can get lovely sunny days in winter, then frosts overnight).