Educate me about humidity levels please?

[gardening_gal]

After having bought a basic weather station to monitor temps in my polytunnel, I find I'm becoming rather addicted to the ins and outs of temperature monitoring.

I've read things on the net about humidity levels also being important in polytunnels but it's usually just a general 'excess humidity levels are to be avoided' type of comment.

I can't actually find anything that tells me what an 'excess humidity level' actually is (in figures, I mean). I could be sitting quite happily watching my humidity level go to 80% and be completely unaware that figure would be classed as 'excess' iyswim.

So, how do I know what kind of figure would be classed as average/normal/desirable for inside a 6m x 3m tunnel?

Am I right in thinking too high a humidity level is when problems with rot, fungus and mould might set in?

[andy_j]

t would depend on what you're growing. Most of our plants for bedding or our veg really doesn't require any additional humidity than what our glorious summers offer us. Occasionally, if it's a warm day, I might damp down the paths of the greenhouse where the toms, cues and chillis are growing, but it's not essential. I never damp down on cold, dull days as too much water laying around can cause problems.

However, if you're growing hot house plants....stuff from the tropics, they thrive on humidity. When I looked after the palm house for Brighton parks, I was damping down every hour to keep the humidity as high as possible.

Personally, I wouldn't get too worried about humidity levels, there are thousands of growers who don't bother.

[gardening_gal]

Personally, I wouldn't get too worried about humidity levels, there are thousands of growers who don't bother.

I'm more interested than concerned tbh. I'm just finding it difficult to get factual info anywhere.

[Potstubsdustbins]

Probably because it is such a variant with each plant requiring different levels. I know one gardener who has one GH for toms and one for cumbers. He keeps the moisture higher in the cumber house whilst keeping the tom house a lot dryer.

[gardening_gal]

Probably because it is such a variant with each plant requiring different levels.

Yes I expect you're right. I do find it a bit surprising though, you can find all sorts of stuff about recommended temperatures and what plants like what type of heat etc, but there seems little about ranges of humidity. I would have thought there would have been even suggested broad ranges rather than set specifics but I've yet to come across anything.

It's not an issue, it's just something I wanted to learn about.