Cold exposure truths

[Bradfo69]

O.k., I admit it. I worry too much. I've got not one, but several thermometers around my greenhouse which, by the way, is only 8 x 15. Two of them are even the wireless type that radio back temp and humidity into the house where the receivers sit on my nightstand.

I have a mixed collection and keep most of the paphs and phals in the house as opposed to the GH.

I've been having some issues in settling on a heat system and the plants have had some up and down periods, maybe a night at 62 then a night at 51 then a night at 57 etc. Sometimes I notice it's 51 at 5 p.m., turn it up a bit and it's 57 at two a.m. I will get it balanced out but the other night at around 7 p.m. it was already 53 but supposed to get much colder that night so I added a second space heater before going out for the evening. I didn't trust the first one to operate properly. Well, a circuit breaker tripped shortly after that and I arrived home at 10:15 p.m. to readings between 41 and 43. I quickly reset the breaker and within minutes got the temp climbing back up. I changed out a heater and eventually things spent the night around 53.

How worried should I really be? They didn't approach freezing. It was only for an hour or so. They've had a dip to 47 once before. I'm I too obsessive about all this?

[cb977]

Hi Brad,
In my orchid room, which is 12 x 28, I only put out the portable electric heater on nights that we're expecting temps below 50. I set the thermostat at 49 so if the temps dip below that, the heat goes on. This is what I've used for the past two winters here in Florida, we don't get many nights with temps that low and when it does dip, it's not an extended period of time. So far, I haven't had any problems except for maybe a little twisting in the vandas...but they all bloom beautifully when the time comes so...

I'm sure our other friends here will chime in with their advice...read all of it and then decide what works for you

[minicatt]

You don't mention what you're growing?
Most orchids can take limited exposure into the 40's with no ill effect. Even so called warm growers will break into flowering after a cold spell!
I think you are worrying too much at this point.
One note of caution though, orchids can seem to take cold when they are on the dry side. Cold and wet is usually not a good combo!
Peter.

[Ray]

The smaller the volume of a greenhouse, the more rapidly the temperature will vary as the heat goes on- and off.

A lack of decent air flow (24/7) will also allow a lot of stratification, but even with it, you will see some "zones".

Set the thermostat to your desired minimum in the coolest part, and forget about it.

[Don Perusse]

I live in SW Ga. where the temps drop to freezing. (Like tonite, suppose to be between 28-32, Nov. 16th)
My grnhse is 10X11 and I only use a very small electric heater from Lowe's with a temp. control. I set it so it doesn't drop below 50 degrees. I grow a fairly large variety of orchids (175 or so) and never have had any trouble. Never lost any because of the cold.

[Phantasm]

If you have wireless temperature recorders, then perhaps they have alarms that you can set when the temperatures get too cool. Depending on what you are growing, I would keep the night temperature between 55-60F if possible. It will of course be a bit higher and lower depending on the weather. Insolate you greenhouse as well possible as you can lose a ton of heat if it isn't sealed fairly well. Double walled is even better.
You are pretty much micromanaging it at this point, but all you need is one night of freezing temperatures to kill your entire collection.

[Daemos]

You don't really have to worry about the cold especially if you are having blue type orchids. I don't have heating on my vanda throughout the whole winter and temperatures indoor drop to 10-12 C for 6 months. All the poor guy done so far is dropping the smallest two leaves but I blame that to the huge lack of sunlight.

[Bradfo69]

I noticed it's been three months since I first started this post and thought I'd update it for those that replied.

I'm pleased to say I did get everything balanced out. After a traumatic experience with propane, I bought a 240 volt electric heater (wall pack) mounted it to a frame and have run it at nearly as low as I can set it. Temps have stayed a consistent 58-61 at night with daytime highs getting to wherever they get with the sun and ambient temperature. (Cost has been about $100 per month for electric.)

I actually think I've been running it a bit too warm as I have continued to have steady root and foliage growth from many plants throughout the winter. My deciduous plants have pretty much lost their leaves and gone dormant but many others continue to develop and I've begun to repot the occasional plant already. The vandas don't appear to have done anything except lose an occasional leaf.

I'm thinking next winter should drop a little cooler. 53-55perhaps.

[Ray]

Brad,

I'm just a few miles north of you in Bucks County, PA, and I have my GH temps at about the same minimum as you - but my phals and paphs are out there, not inside.

I am seeing a lot of growth now too, and have several things from the southern hemisphere in bloom or spiking.

[Bradfo69]

Thanks Ray. I know you're nearby (and I've heard you speak on a few occasions - we've met.) I have the majority of my paphs and phals inside under lights although there are a few out there that are doing well -including a large Paph honey I bought from you (in semi-hydro) in 2003 or 4 when you spoke to Delaware Orchid Society. It finally bloomed about six weeks ago and got "awarded" at our show table.

I think I could (and perhaps should) go a little cooler next year but I'm still concerned about the vandacious types. I'm predominately intermediate but have a few things that fall into both the cool and warm categories.
(You can't be in a society with Malli Rao and not have a few masdies!)