I am intending to use cut off 2 litre plastic bottles as cloches. Does it matter if they are gree? Or must they be clear plastic?
Welcome to the site JD... my gut reaction is to use just the clear ones... maybe someone has used the green ones and will tell us it's OK... :-\
Hiya, JD, welcome to a4a ;D
another vote for clear but only 'cos I can't get green ones :)
What about plastic milk bottles, or are they too opaque? (I have a feeling I've asked this elsewhere but didn't get-or didn't read- an answer!)
Definitely clear.
Another cheap option and one that I use, is to collect the wire coat hangers from dry cleaners, open them out and cut off the curly bit and use as the frames, use fleece, enviromesh or even cheap plastic from Wilko's over the frame and held down by bricks, planks or anything else I can get my hands on.
Cost virtually nothing, and the produce grows just the same as my neighbours in his expensive aluminium and corrugated plastic ones at £40ish.
Only used the clear water bottles as mini cloche, although have used the green plastic bottles purely as overnight frost protection.
If you have access to the water cooler type plastic bottles used in offices etc, make the most of it. Some of them are quite large.
just bought large M&S "house salad" - great mini-cloche! (after you've eaten the salad of course!
Hemisphere, about 6" across and 3-4" deep
plastic water pipes cut to lengths make nice little cloche arches too, they do not cost a lot. And store easily.
Platic bottles are far too fiddly you get one plant under each, there is not enough weight in them to stay up easily, and they look a total mess.
I think every body tries them. Once. Clear are best opaque nearly as good, coloured, better than nothing.
Green plastic filters out everything except green light; that's why it's green. Leaves absorb everything except green light; they're green for exactly the same reason. If you use a green cloche, you take out everything except the light wavelengths the plants don't use anyway! So they're far from ideal.
Quote from: PurpleHeather on March 21, 2009, 08:59:11
plastic water pipes cut to lengths make nice little cloche arches too, they do not cost a lot. And store easily.
Platic bottles are far too fiddly you get one plant under each, there is not enough weight in them to stay up easily, and they look a total mess.
I think every body tries them. Once. Clear are best opaque nearly as good, coloured, better than nothing.
Personally, I wouldn't be without them for individual plants like squash and chilli and giving them a head start. I put a cane next to the plant and slide the bottle down the cane and over the plant. And, I couldn't give a toss if some people think the 'look a total mess'!
Oh, and on topic - I only use clear one - the bigger the better. I find 5litre spring water bottles excellent.
Green as a permanent cloche is a no no. As mentioned green light, which is all that will get through, is useless to plants, they only use blue and red light, and light at the end of the spectrum invisible to us. In effect plants 'see' almost the exact opposite of us, we see a bell curve through the spectrum, plants see a narrow band of blue and a broad spectrum section at the red end, they are 'blind' to mid spectral light.
Personally I think any coloured bottles should be avoided, as they will filter most of the spectrum. A plant will grow happily in just blue light, but will not be likely to develop flowers and thus fruits.
However even blue plastic is likely to be detrimental to even vegetative plants, like lettuce, because not all of the blue spectrum will pass through, just the particular wavelength that matches the colour of the bottle and teh desired blue is a very narrow part of the spectrum.
So clear it is.
Does that mean that green-tinted plastic greenhouses and cloches should be avoided?
Quote from: lewic on March 21, 2009, 21:57:51
Does that mean that green-tinted plastic greenhouses and cloches should be avoided?
Hmm...
It's complicated, shade plants are perfectly happy in green light at the bluer end of the spectrum, but sun loving plants will not thrive. But these tinted plastics are not particularly dense and are unlikely to eliminate all none-green light. Additionally plants can photosynthesis some green light, just not much of it, resulting in stunted yellowed growth. Some plants have other pigments, which photosynthesis other wavelengths, such as Chlorophyll b and caratanoids.
I can see no benefit to green tinted plastics, so I'd avoid them.
Plants often need shade if they're in a greenhouse. I used to grow cacti, and they'd get burnt without it. Green is more for our benefit than the plants' though, and I never used it.