Backyard Greenhouse Moisture Problems

[Bigdope916]

Hi guys,

I just set up my first greenhouse grow but am having some problems with humidity. I am using a Flowerhouse 5ftx5ftx6.5ft I bought from Home Depot. I have two 6 inch clip on fans running 24/7 and 5 plants, all of which are in 15 gallon smart pots. I just put in the clones today which are small but I watered the whole 15 gallons worth of soil. Humidity has stayed around 88% but shoots up to almost 100% when I close up doors. Temperature was mid 80’s today but upwards of 95 degrees in greenhouse. My greenhouse has two doors on opposite ends with a mesh screendoor behind it as well. There is no other vents besides the doors and I’m curious what the best way to keep temperature and humidity in the right levels is under these circumstances? Do I need to keep the top of door open at all times? Should it ever be fully closed up? Also it is going to rain tomorrow.. should I be worried about rain coming in through doors? Any help is greatly appreciated

 

[Bigdope916]

Hi guys,

I just set up my first greenhouse grow but am having some problems with humidity. I am using a Flowerhouse 5ftx5ftx6.5ft I bought from Home Depot. I have two 6 inch clip on fans running 24/7 and 5 plants, all of which are in 15 gallon smart pots. I just put in the clones today which are small but I watered the whole 15 gallons worth of soil. Humidity has stayed around 88% but shoots up to almost 100% when I close up doors. Temperature was mid 80’s today but upwards of 95 degrees in greenhouse. My greenhouse has two doors on opposite ends with a mesh screendoor behind it as well. There is no other vents besides the doors and I’m curious what the best way to keep temperature and humidity in the right levels is under these circumstances? Do I need to keep the top of door open at all times? Should it ever be fully closed up? Also it is going to rain tomorrow.. should I be worried about rain coming in through doors? Any help is greatly appreciated

I am Northern California by the way

 

[redshift75]

you need circulation to circulate the air out. those flowerhouse tents are designed for high humidity. Says its right in the sales info. Typically kit greenhouses either sell the screens or come with them. Then that would be the indication how they are intended to vent. So if the screen has the mesh bug protector you want that closed but door slightly open. My greenhouse designs i typically have have 1 or 2 vents i can open at the top of the roof. With each end having auto vents to open if it gets too hot and i do roll up curtain sides. my small plastic greenhouse that acts more as my storage/sunlight hardening house for certain trays. Is the same way where it cooks everything. I ultimately modified it to have a 10" fan that was like $30 at tractor supply and run it off a heating mat controller.


The goal to keeping humidity down in greenhouses when you need to control it (from either temps or too little air flow) breaks down to the moisture you put in to the tent(the more water that is used outside the plants needs) and the airflow it has. But in California weather i imagine you would have to maintain constant airflow at minimum using those doors. Humidity that high you should be able to keep it in check with the screen closed and door slightly cracked. Venting to the top of a greenhouse is typically best way. vents open on bottom with vent open on top to create that airflow path. Ive seen those flowerhouse before and i thought they have 4 vents on the bottom that are like 4"x4? or is that a different model?

 

[redshift75]

yeah i just looked it up. Looks like they changed the design in past few years. So im guessing they designed it now so the doors are the vent solution. They dont have the vent above the door anymore. I see it on there info now "The large screen door allows for optimum ventilation and pest protection. "

 

[Bigdope916]

yeah i just looked it up. Looks like they changed the design in past few years. So im guessing they designed it now so the doors are the vent solution. They dont have the vent above the door anymore. I see it on there info now "The large screen door allows for optimum ventilation and pest protection. "

Okay thanks redshift.. yeah I’m just going to have to leave one or both of those doors cracked. This was not my first choice of greenhouse but everywhere is sold out of everything and after 4 unsuccessful purchases I settled for this one. Took me over 2 months to finally get it. Also, what do you think a healthy humidity level is for the veg stage? I just got the clones two days ago and they are about 8 inches high. Thanks