Greenhouse Planning... Sounds boring right? It is... But its all in the details!
So here I will go over my choices in equipment and greenhouse and the reasons why I choose what I did.
Starting with the greenhouse- I bought a ACF "Grow More" Greenhouse. I started with a 13x20 unit. The starting cost was 4400 dollars. Reasons I picked this unit was its heavy duty frame, 10mm Triple wall panels, Unit expandability in 2 meter sections, ease of building, Aluminum construction, and snow load and hurricane ratings.
I purchased a Mr. Heater 50,000 Btu Overhead Propane Heater.
Reasons for this unit was cost, reliability, low cost of maintenance, and cost of propane (we dont have Natural gas hook ups so we must use propane)
I sized the unit about 10,000 btu over what the heating load would be on a 5 degree night. I suggest you do this for two reasons. Future expandability, and excess heating capacity might be needed in case of severe weather.
Cooling? What? Well yes... If no venting or shade cloth is provided the greenhouse hits 120-130 degrees with ease... Unless you want to grow cactus, this isn't Ideal. Especially for daylilies. So what do you do???
Shadecloth, Florida daylily growers typically use 40-60% shade cloths over their plants. Same concept here applies. You are reducing the total solar radiation gain in the greenhouse, while still getting plenty of light to the plants. I purchased a 50% Aluminet Shade Cloth. I choose Aluminet because it will reflect the sunlight rather than absorb it as a 50% black or green shade cloth would further reducing temperatures. My cost was 240 dollars.
Power or passive.
You must move the hot air out! The design of this greenhouse has 3 roof vents built in. I use temperature sensitive automatic vent openers that open the roof vents as the temperature inside the greenhouse rises.
Power venting. I don't use a fan here, I use a swamp cooler for my power vent.
Whats a swamp cooler? A really cheap and effective air conditioner really. It uses evaporative cooling to produce air that's roughly 75-80 degrees depending on the ambient air temperatures. It also has the added benefit of adding humidity to the air.
Why did I go this extra step? Well one was the lower cost of the unit, next was the effectiveness of the unit. I wanted to be able to make crosses no matter how hot it was out. This means keeping the Greenhouse under 85 degrees is a must. The swamp cooler vents at roughly 4400 cfm and the incoming air is 75-80 degrees. This, coupled with the shade cloth as made it possible to have the greenhouse COOLER then it is outside. A big must come June...
Cost? 450 dollars... Note this unit needs an active water supply and power.
Other small "greenhouse" items
Fans, these are a must... Moving the air around is important.
Shelving- I use chrome wire racking for the seed growing, and trays.
For the pots I built tables, with a plastic grid-
Workbench, this is a must- Again I just built one from 2x4's and plywood.
Lighting- Pretty important, but for now I just repurposed (3) 4-lamp T-5 Grow lights. I will change this in the future, but I had these and I wasn't using them.
There isn't much more major equipment to address here.