Where should my humidity levels be throughout my grow?

We've often explain how the climate for hydroponics project is super-important, but many growers just don't have enough opportunities to talk to each other about how to set up grow spaces. What about the right temperature and humidity for hydroponics projects?

Well, when it comes to humidity, the answers that you're going to get are all over the map. Ideally, humidity really has to do with the grower’s overall strategy -- what kinds of things he or she is most worried about, and how he or she feels plants are going to be best supported.

Not Too High

Look around the Internet, or go to a convention and talk to growers about humidity, and you're likely to hear a lot about how you need to keep humidity fairly low, below 50% real humidity. And the overwhelming reasons you’re going to get for this is that more humid conditions can allow for more mold and mildew.

Simply put, growers are scared of these kinds of environmental conditions, as well as various types of plant rot that can happen in excessively damp environments. We know this intuitively, the same way we know that mold can really do a number on a home or property. So by keeping humidity lower, you're making sure that none of these nightmare scenarios happen in your grow room.

Not Too Low

However, you may see other growers talking about keeping real humidity at 50% to 80%, or warning against keeping humidity down in the 20% to 40% region. They're arguing from another angle, one that has to do more with plant development.

Some growers talk about the plant's ability to ‘transpire’ -- plants take in water vapor as part of natural growing processes. So you don't want it to be too dry in a space, or it can affect plants a lot. You can get withered plants, or plants that seem excessively dried or they just don't seem to thrive well.

Growing Stages

There's also a more sophisticated strategy that some growers take, which is to gradually lower humidity as time goes on.

For the new seedlings, they keep humidity fairly high at 80%. That makes it easier for plants to transpire and grow when they are young and sensitive.

At the vegetative stage, you might have humidity at about 2%, a good middle ground that allows plants to transpire while also protecting them more from mold and mildew.

Then in a flowering phase, humidity is set even lower, to prevent rot on fruits or buds.

These are just some basic strategy that growers use to support plants. For more, check out the Dealzer webpage and see how you can start your very own hydroponics project today.