Is this a good idea to increase humidity
 

Hi. We moved into a new house a few weeks ago and since then I’ve been actively setting up a little shade house as a Home for my orchids. The shade house is small, old and shabby, and oddly is set into the hillside so only the top third gets decent ventilation and therefore is usable for orchids.

The whole house is old and substandard and we intend to bulldoze everything on the block in a year or so and build a new house - so I’m very reluctant to spend time or money on what is there. It’s really hard to see how I could improve my growing environment anyway with the space we have.

Anyway, the floor of the shade house is concrete, with benches on three sides. Below the benches is a double row of concrete blocks set vertical so as to create a kind of U shaped pond (see the attached image, which appears to be upsidedown). If I fill the structure with water it retains water about one inch deep.

My questions are
1) Can anyone guess what this could have been intended for?
2) If I keep it full of water, will it raise the humidity in the shade house?
3) would that be a good thing, or is there a downside I should be aware of?

Background; we live in a seaside location just north of Sydney, Australia. I grow largely Cattleyas and oncidium alliance hybrids. Temperature is probably a bit on the cold side for these plants, though they get by. I’ve never been sophisticated enough to measure the humidity locally but my feeling is that all of these plants would prefer it higher.

Cheers
Arron

1. Not a clue
2. Probably will raise it a bit
3. Unless you can manage to circulate the water, you're likely to breed mosquitoes. Probably not such a great idea.

My climate and yours are very similar (in southern California I'm about as far north as you are south) Zone 10b where I live near the coast. If anything, I think you have more humidity than I do, and I have not seen it to be a problem for Catts or Oncidium tribe. I grow a wide range of Cattleya species outside - just a bit of overhead protection from rain, and I'm sure this works for you as well. Would some of them like more warmth? Probably but they get what they get and in general, adapt just fine.

I wish I could be helpful, but I live in a relatively warm area, grow indoors, and use cool-mist humidifiers. That said, the "concrete pool" you've shown worries me. It looks like a breeding pond for insects. Were it in my growing area I'd keep it dry.

Ok, thanks for the responses so far. I wouldn’t focus on the mosquito breeding issue though, I will manage them by letting it dry out ever few days which it is want to do anyway.

Roberta I think where you are is quite a bit warmer on average then where we are. Unfortunately the zone system doesn’t really map very well to Australia.

I’m really just wondering if there’s anything I’m overlooking about artificially supplied humidity. I guess I wouldn’t want it happening when the cold weather is occurring.

As to the shade house not being appropriate for orchids due to ventilation, have you considered a small fan?

Well, in summer temperature is only rarely above 32 deg C, 90 deg F (there are a few hot days, but on average it's below that) with nights typically around 20 deg C (68 deg F) plus or minus a degree or two. In winter, while we also get some warm days, usually highs stay below 22 deg C (72 deg F) and most of the time several degrees lower... nights can get close to freezing (2-3 deg C, 35 deg F) occasionally, mostly a few degrees above that, like 4-6 deg C, 40-42 deg F. Does that sound familiar? Go even 10 km (6 miles) farther inland and it does get both hotter and colder. I love living near the coast and so do my orchids!

Filling the trough with gravel would eliminate areas of standing water and still provide the humidity.

This might be a useless suggestion but if you were to fill that water reservoir isn't there some sort of a small pump you could use to keep the water moving? My question about that water there would be bacteria and that kind of stuff but I think the water could also be treated. Another thought on humidifiers as I grow indoors as well you could do a combination of evaporative whole house humidifier which really does a very large room and a cool mist humidifier. Small fans are a must to keep the air moving throughout. Just a thought?

How much extra humidity is actually needed in coastal NSW? I suspect my climate is a good bit drier though similar in temperature. We complain mightily when daytime humidity in summer hits 60%, most of the time it's closer to 40% except when the desert winds blow... earlier this week it was below 10% and the only things that suffered a bit were some mounted Pleurothalllids. Solution to that comes out of the end of a hose.

No, it never even occured to me. There is no mains power to the shadehouse or anywhere close to it, but a couple of solar powered fans would do the trick, I think. Thanks.

---------- Post added at 07:13 AM ---------- Previous post was at 07:02 AM ----------

I thought it was a given that more humidity would be a good thing, but now that you have questioned it I’ve spent some time studying climate data and now I think that we don’t need it.

At least it’s not likely to be needed, there are two published weather stations in this district but neither seems to line up very accurately with what we get right here. It’s the microclimate that is important and because we’ve only just moved to this place we aren’t really sure what to expect.

It’s certainly more humid here then Roberta’s climate. Not as humid as the published data from most of the South American cities nearest to where the plants originate, however.

Thanks for putting me straight on this. I’ll wait to see if it really is needed before I do anything.

Cheers
Arron