Polyhouse heating for Orchids
 

Hi Guys,

Need your inputs on getting a good heating equipment.
I stay in a area where I do not get frost but the minimum temperature touches 3 to 4 C for a week during nights. Average lowest temperatures would be 6 to 10 C during nights and upto 18 C during days of winter.

I am growing orchids in a mini poly house of 8 Feet wide 4 feet deep and 8 feet height. For ventilation, I keep the entry curtain open for ventilation. Sun would be direct on greenhouse from 10 AM to 1 PM approx.

I am growing Phals, miltonias, catts, Vandas, Rhycostlis, Dends, Gramatophylums Paphs and HTC Cymbs. And few other Anthuriums.

Now please guide me how to get a heating set up for winter.
Use 2KW common blower on 1 KW settting controlled by a thermostat?
OR
Use a Halogen heater with 3 rods (400W each) with one or two switched on?
OR
Use a tubular heater with the thermostat setting of 120 W (3 feet or 4 feet)
Or
Use 200W frost control heater .. seen on EBay claiming it is similar to 4 feet tubular heater on functionality.

Please guide me, or any other better idea if you have please share.

1) You're going to need to close it up. Leaving openings for ventilation is leaving openings for escape of heat, and your heater will need to be much bigger to overcome that.

2) Heater Size Calculator

Thanks Ray, for your response, I was going through your website pages and I got your response. With the calculator I got I need 1k electric heater.

I will certainly close the curtain in colder days, But I am puzzled about choosing a right setup.

I am inclined towards using Halogen lamp with 400 Watts and a fan side of it, to circulate the air from the lamp.
Is it good?
Or go with a blower with 1000 Watt and Thermostat controller?

Thanks again

I would use a space heater and an isolating fan. Poly houses leak quite abit so I would oversize your heater.