Greenhouse humidity

taylorjoseph422

Hey there, I'm new to this and need a little input. In my 8' x 8' greenhouse I planted tomatoes and eggplants. Is there a specific humidity and temperature I need to preserve in it for them to grow ok? Any tips regarding fertilization are more than welcome too.

Pete.8

Hi and welcome to the forum
I don't grow aubergines but I do grow tomatoes.
Ideally the temperature wants to be somewhere around 25-30c during the day and tomatoes don't like it too humid. At night they don't like temps below 12c for long periods.
I grow cucumbers too which prefer more humidity, so they are at the opposite end to the door.
I leave windows and doors open this time of year onward when the weather is nice, so that pollinators can do their work, and this stops the humidity and temperature rising too much

On very hot days shading is very useful (old net curtains are good) and you can 'damp-down' the floor (i.e. just spray the floor with water) which will help lower the temperature a bit.
Tomatoes don't need any feed until the first fruits begin to appear, then use a tomato feed weekly.

Kili

Yeah, what Pete.8 said in a nutshell.

RilesJasmine

Tomatoes don't tolerate high humidity, like Pete.8 said, and since you have a greenhouse, you can keep things under control with a dehumidifier or maybe an evaporative air cooler that can help you keep temperatures within the recommended range if it has the option to raise and lower them.
Temperatures during the day should be at 70-80 F, and during the night at 60-65F. When it comes to moisture, some sources say it should be below 90%, but I'd recommend a more specific point - at about 55-65%. This way, you prevent leaf mold that is disastrous for the crop.
When it comes to fertilization, reduce it as the fruits ripen. When the weather is cold, only fertilize if you use a heater in the greenhouse, otherwise, avoid the procedure altogether.
And please remember to harvest as late as you can, if you want good tasting tomatoes, they should be as red as possible.
https://www.wikihow.com/Grow-Tomatoes-in-a-Greenhouse
https://www.optimainstitute.com/dehumidifiers/for-basement.html
https://popular.reviews/portable-evaporative-cooler/
https://homeguides.sfgate.com/plant-tomatoes-greenhouse-52925.html

Pete.8

I've been growing tomatoes successfully for over 50 years without a heater or a dehumidifier or a humidifier.
If it's hot open the doors and windows, if it's chilly close them - works for me

Butterfly66

We grow aubergines and tomatoes, @Pete.8s advice is pretty much what we do and seems to work well. We have blinds on the south-west facing side of our greenhouse and they are pretty much permanently down from early June onwards so that helps keep temps down.

Kili

Pete.8 said:

I've been growing tomatoes successfully for over 50 years without a heater or a dehumidifier or a humidifier.
If it's hot open the doors and windows, if it's chilly close them - works for me

Me too. Open the doors or close them what ever the weathers doing is your barometer. No need for expansive air ventatlion systems unless your running a commerical operation then its vital.