Hi guys
This winter is my first winter grow in a greenhouse - prior to this I've grown peppers in a cupboard where it was much easier to maintain reasonable temperature.
Last few days we've had temperatures drop down to about 50F, my greenhouse thermostat is currently set to 62F and starts a 400W panelheater with a few fans which help distribute the air across the greenhouse (it's 6'x8'x6'). I log the temperature and can see the lowest that it dropped to was 55F. I also have a 400W HPS light that comes on at about 3am and I saw an increase in temperature about that time which went up to 60F, so the light definitely helps.
As you can see from the graph below (taken over the last month) the last few days the night temp started dropping significantly (temp in C, also ignore the reading of 0C a few nights ago - the sensor crapped out):
The greenhouse has insulated floor and polycarb walls/roof with 4mm airgap. I have also closed off the vents I kept open in summer.
With the current power consumption I'm going through about 5-7kWH per day with the lighting and thermostat-controlled heater. (this includes the fans, aquaponics water and air pump, cooling fan etc) but 90% of all power is taken up by heating.
After doing a lot of reading here and elsewhere I reached a conclusion that if night temperatures reach low 40F then this will slow the plants down by as much as 20% (until fruiting, etc). If they are kept above 50F then the reduction in fruiting time is only about 10%. Does this sound right?
Also if anyone else is heating their greenhouse, what methods do you use - fan heaters are definitely much quicker to warm up the place but they do chew through quite a lot more power, especially if its a 2.4kW fan heater.
I've read about some people digging out floors in their greenhouses and filling it with compost - and having compost heat up the greenhouse, the dimensions of my greenhouse won't let me do that I don't think. I also thought of using gas, but it didn't seem more efficient. I don't have much spare space inside - otherwise I would've use full water barrels, painted them matte black and let them slowly release heat during the night - although I do have some space under the aquaponics bed which does get a bit of sun for a few hours a day.
Any ideas or suggestions would be appreciated.
This winter is my first winter grow in a greenhouse - prior to this I've grown peppers in a cupboard where it was much easier to maintain reasonable temperature.
Last few days we've had temperatures drop down to about 50F, my greenhouse thermostat is currently set to 62F and starts a 400W panelheater with a few fans which help distribute the air across the greenhouse (it's 6'x8'x6'). I log the temperature and can see the lowest that it dropped to was 55F. I also have a 400W HPS light that comes on at about 3am and I saw an increase in temperature about that time which went up to 60F, so the light definitely helps.
As you can see from the graph below (taken over the last month) the last few days the night temp started dropping significantly (temp in C, also ignore the reading of 0C a few nights ago - the sensor crapped out):
The greenhouse has insulated floor and polycarb walls/roof with 4mm airgap. I have also closed off the vents I kept open in summer.
With the current power consumption I'm going through about 5-7kWH per day with the lighting and thermostat-controlled heater. (this includes the fans, aquaponics water and air pump, cooling fan etc) but 90% of all power is taken up by heating.
After doing a lot of reading here and elsewhere I reached a conclusion that if night temperatures reach low 40F then this will slow the plants down by as much as 20% (until fruiting, etc). If they are kept above 50F then the reduction in fruiting time is only about 10%. Does this sound right?
Also if anyone else is heating their greenhouse, what methods do you use - fan heaters are definitely much quicker to warm up the place but they do chew through quite a lot more power, especially if its a 2.4kW fan heater.
I've read about some people digging out floors in their greenhouses and filling it with compost - and having compost heat up the greenhouse, the dimensions of my greenhouse won't let me do that I don't think. I also thought of using gas, but it didn't seem more efficient. I don't have much spare space inside - otherwise I would've use full water barrels, painted them matte black and let them slowly release heat during the night - although I do have some space under the aquaponics bed which does get a bit of sun for a few hours a day.
Any ideas or suggestions would be appreciated.
