when to start heating greenhouse

Geodark

Just got myself a greenhouse this year, and with the temperatures starting to drop on a night I was wondering when you money saving experts kick the greenhouse heaters away. I live in the north east and over the next couple of weeks the temperature is forecast to drop down to 7 degress on a couple of nights. just wonder what effect this would have on my tomatoes, melons, sweet potatoes etc.

Davesnave

Geodark wrote: »

Just got myself a greenhouse this year, and with the temperatures starting to drop on a night I was wondering when you money saving experts kick the greenhouse heaters away.

Err.....never!

When I used to run a plant business, it was worth protecting some plants with a greenhouse heater set to 0c, but now I don't, I can't find much justification for wasting money and resources like that.

This morning, it was 7c where I am. I don't think the sky will fall in for my tomatoes, cucumbers and peppers, nor yours. It's still only August!

Geodark

Davesnave wrote: »

Err.....never!

When I used to run a plant business, it was worth protecting some plants with a greenhouse heater set to 0c, but now I don't, I can't find much justification for wasting money and resources like that.

This morning, it was 7c where I am. I don't think the sky will fall in for my tomatoes, cucumbers and peppers, nor yours. It's still only August!

Cheers Fella, probably just being a bit paranoid then :rotfl:

A._Badger

Geodark wrote: »

Cheers Fella, probably just being a bit paranoid then :rotfl:

It all depends on what you are growing. I'm in the South so it's warmer here and my greenhouse is well insulated. I won't be thinking about heating until the first frosts and then all I will do is set my thermostat to a minimum of just a shade over 40 degrees F. At that temperature the plants I want to keep (mostly pelargoniums, fucshias, cacti, citrus and a few specials that I like to hang onto because they are hard to find, like Tweedia Caerulea) will survive and tick over till spring.

Some people argue that it isn't worth the cost of heating a greenhouse and that it's cheaper to buy new stock each year. It may be (though possibly not in my case as some things, like regal pelagorniums of specific varieties, citrus and specimen cacti can be costly,) but you can't always find the varieties you need. In any case, a well insulated house with an efficient heater isn't too crippling to keep above freezing, I find.

As for now, it's worth knowing that tomatoes effectively stop growing at 45 degrees F (which I think is around 7 C). But they won't suffer damage at that temperature and they certainly aren't worth heating a domestic greenhouse to grow!

Hope that's some help.

Davesnave

A._Badger wrote: »

Some people argue that it isn't worth the cost of heating a greenhouse and that it's cheaper to buy new stock each year. It may be (though possibly not in my case as some things, like regal pelagorniums of specific varieties, citrus and specimen cacti can be costly,) but you can't always find the varieties you need. In any case, a well insulated house with an efficient heater isn't too crippling to keep above freezing, I find..

I agree a well-calibrated, decent quality electric heater is relatively cheap to run in a small, bubble insulated space. Remembering to ventilate in the daytime then becomes an important aspect too.

Most greenhouse heaters are set to frost stat at around 5c, but being tight, I re-set mine to much closer to 0c. In all honesty, I don't remember losing a pelargonium to frost, though I lost a few to botrytis. Some of the old toughies like the oak leaf variety survived fine in soil outside against the house wall, more often than not.