Got a question about the humidity in my greenhouse right now. I have a hygrometer that tells me I am running at or just below 90% humidity.
I don’t have much in the greenhouse right now: 3 lettuce that are growing slowly, 6 Calluna that I am storing until the spring, about a dozen strawberry plants and my Meyer Lemon bush.
From what I have read, that is a little too high for the plants and what I am most concerned about is the aluminum structure (ribs of the building, if you will) rusting with all of the humidity. It is a Planta Sungrow 20.
I have reached out to the manufacturer, but wanted some input from local gardeners. Should I invest in a dehumidifier or desiccant to reduce the humidity? Like I said, not worried about plants - they seem happy enough, but it is the metal inside of the greenhouse that I am concerned about. TIA
Aluminum does not rust like iron based metal does. You will see the aluminum go from a bright shiny surface to a more dull surface, which is the surface of the aluminum oxidizing. That is the extent of the aluminum weathering.
The aluminum greenhouse we have has been around for probably 20 or 25 years, and it is still very sturdy. The humidity in our greenhouse is around 93% this time of the year, and there is condensation dripping and running down the inside of the glass. Welcome to the west coast, or is that the wet coast?
Thanks for the great answer to this Gordon. Sylvia’s question made me wonder if there is an optimum level of humidity in a greenhouse. This question has been forwarded to the Vancouver Island Master Gardeners for their input.
As a reminder to other CVHS Members/Forum users, questions asked on our Forum will be automatically sent to the VIMGA – so please ask away and we can all share in the excellent advice provided!
Thanks to everyone that responded with their opinions. I wanted to post the response I got from the company (Planta Greenhouses) … on a Sunday(!):
" The frame is processed with a galvanized steel zinc coating and we want to assure you that minor rust on stainless steel profiles is not uncommon and is typically a surface-level issue that can be easily addressed. Rust on stainless steel is generally a superficial issue and does not indicate a failure of the material. You can use a stainless steel cleaner available at most hardware stores. These cleaners are specifically formulated to remove rust and protect the surface.
If the galvanized steel frame fails by cracking or having abnormal rust build up we will replace all parts necessary at no additional charge. Make sure to not scratch the zinc coating on the metal parts to prevent exposure of the steel to the outside. If for some reason the surface has been scratched the surface of the metal parts it is recommended to coat it with any acrylic base paint(copper paint, lithium paint etc.)."
And the Meyer Lemon looks happy - she hasn’t lost any leaves and I have not noticed any frost on her, but will keep my eye out for that.
