Coping with fog

[aloedanielo]

I live in Hope Valley famous for its cloud inversions. We regularly have fog that comes right over the valley. Sometimes it’s so thick you can’t see our next door neighbours and it looks like the world stops at the bottom of our drive.

People travel from far and wide to get a photo from above the clouds. We’ve just got used to it!

My question is, how do people cope with fog and cacti? Surely fog will still penetrate a greenhouse no matter how much insulation etc?

[iann]

Humidity will steadily rise even with the greenhouse shut up tight. Its inevitable. You can either run a dehumidifier, or just rely on lots of air movement probably from fans. Might want to start with a gadget that actually measures the humidity - they tend to be somewhat inaccurate especially up towards 100%, but at least it will give you a gauge for when to ventilate, when to shut up and just use the fan, and whether you really need a dehumidifier. Heating plus ventilation is a way to keep the relative humidity down, but not perhaps to keep your electricity bill down.

It is hard work here in humid, but not very foggy, Greater Manchester to get the humidity below 90% for even a part of each day. A useful goal is to clear the condensation on the glass every day. Things get better after Christmas when the air starts to dry out the sun starts to come back.

[Phil_SK]

Probably most of the thoughts in el48tel's 'relative humidity' thread apply to fog, too. It is what it is; nearly all plants cope with it.
I didn't think it was possible to make Hope Cement look attractive!

[aloedanielo]

Probably most of the thoughts in el48tel's 'relative humidity' thread apply to fog, too. It is what it is; nearly all plants cope with it.
I didn't think it was possible to make Hope Cement look attractive!

Thanks yes, just saw the Relative Humidity thread - oops!
You know it! I love the cement works, especially at night when it's all lit up. It's a massive welcome beacon telling me I'm home <3

[esp]

In habitat, for many plants it's not a case of "Coping with fog", it's "surviving because of fog" (or dew..), and adapting to collect as much of it as possible.

I just thought I'd seen many references to C&S collecting or using fog or dew, but not seen many (any?) relevant images, so just did a search and here are a few, including a video of a fox licking a foggy, lichen covered cactus (Eulychnia?) in Argentina:
https://www.gettyimages.co.uk/detail/vi ... FBBD3_0153

https://www.atacamaphoto.com/atacama-de ... actus/1138

There was also a recent article of foggy C&S locations in ESR https://www.essexsucculentreview.org.uk ... h-2017.pdf

[el48tel]

Ah yes the Hope Valley works - I remember it well from my days of living not over far away from it. And sunny (not) days in the Mersey and Medlock valleys as a student!
Interesting thought though about "humidity" (see my thread elsewhere) and "fog" --- yes the same problem from opposite sides. I noticed as I was experimenting with the fan heater and InkBird unit that the fan had a greater impact on the humidity than I would expect - air temperature at 6C from natural air temperature was wetter than from the heater and fan running.
I loved the references to the desert fog presumably from temperature inversions as the sky clears; the albedo of a silica surface is high; the earth cools; the warmer moist air cannot convect --- and voila --- an inversion for on which plants must depend and have evolved so to do. But the flip side of this --- the earth will heat rapidly even in winter so evaporating the condensate --- in the Atacama most definitely --- but not so in the UK.

[Chris L]

Don't some of the coastal Copiapoa's get most of their water from fog/sea mist?

http://www.copiapoa.dk/side_b_engelsk.html

Today wel only find the remains of the Copiapoas close to the Pacific coast where there is still some humidity in the regularly daily fog (camanchaca), but very seldom a drop of rain.
Collectors and scientists have often been wondering how the plants were able to obtain the necessary amount of water to survive in the tough habitat. You might have some experience with some theories claiming that the Copiapoas are able to obtain humidity even through the spines and the epidermis. Of course this is only pure imagination - if you have seen the plants in their habitat, you will be convinced that this cannot be correct, according to the lack of spines on several healthy plants with an epidermis looking almost like the skin of an elephant.
On the other hand you will learn that the soil often gets humid or even wet on the surface from the heavy daily fog that comes in from the Pacific. The fog (camanchaca) takes shape on the ocean according to the cold Humboldt-current, which comes all the way from the Antarctic to flow up along the coast of north Chile. The fog frequently blows in and covers the coast, sometimes as deep as 20 kilometres from the coastline.

[Cidermanrolls]

I run dehumidifiers in my greenhouses all winter. Much of the energy they use replaces energy that the heaters would otherwise throw out, so there is compensation. On a ‘warm’ day, the dehumidifiers can push the temperature up to low teens, which is effectively wasted heat, but it does warm the heat sinks of the soil and so all is not lost come evening.
I reckon this to be a price worth paying in foggy North Lincolnshire. Some of us, myself included, pay hundreds of pounds a year on plants. £50 in extra electricity.....?

[D^L]

The West coast of South America and the west coast of Southern Africa both have cold ocean currents running up them and get substantial fogs coming in from the sea. I recall stopping the car, as we drove towards Port Nolloth in South Africa in the evening, because I couldn't believe that I had had to put the windscreen wipers on. I got out and stood there, resulting in my front being drenched as the fog rolled past.
So, yes coastal plants get loads of fog, but during the day it is usually sunnier and hotter than is the norm in Derbyshire I'm not sure this is evidence that they like fog in the UK.

There is an argument that it is these fog inducing currents that were key in the evolution of the succulent lifestyle. Nice idea but I think it is just based on the fact that highly diverse succulent habitats are in these environments, whereas, for instance Australia never had this feature and has next to no succulents. Not aware of anything more than this "coincidence" to support the theory though.
Cheers
David Lambie
Bristol

[phil]

I never use a dehumidifier but have fan running 24/7. Vents open automatically and I always open the door on dry days throughout the winter when temperature is above 7deg C which is most days here in the south.