Garden Fleece/Frost Protection???

Been looking at garden fleece/frost protection. Prices vary enormously, but what I cannot find out is what wieght of fleece to go for. Have found 17gsm right up to 32gsm. Nobody lists what sort of protection 17gsm will give in terms of temperature.

I will be using the fleece in my polytunnel. Most of the plants in there are young perennials, but I have a few tender plants that need a bit of extra protection.

Does anybody have any idea on what level of protection fleece gives, please?

Chopper.

 

You mean like a "tog" rating for fleece?

 

Exactly that DR, thanks.

Chopper

 

What are you trying to protect? Unless they are tender or half hardy, most perennials will survive even harsh winters fine. Planting them out in the border/bed will actually protect them more than keeping them in pots, as their roots are protected in soil that is that little bit warmer than the air temperature.

 

No expert on fleece here, but as I undersatand it - and has worked for me

The lighter fleeces , on a single layer, will give protection from 1 or 2 degrees of frost.
You can plump them up into several layers and they will protect from a more severe frost.

The heavier fleeces will protect from 7 degrees of frost in a single layer - presumably more if you double them but I haven't heard claims of that kind.

Hope that is of some help.

 

If your plants are in pots Chopper it would also be worthwhile sitting them on sheets of polystyrene to help keep the chill from the roots.

(In my polytunnel I lost my three pet oleanders last winter due to not protecting them, though they'd survived the 6 previous winters. Our two olive bushes were frost nipped, though have survived - got over 50 olives on one, though they are tiny ones)

 

I always think of fleece as a spring frost covering.

Cant imagine it ever being much use below minus 2C for more than a few hours.
Continuous frost that we can get around Jan and feb would soon get through a fleece covering.

Its mostly dependant on how long the frost lasts, and I hope we dont get any that last all day this winter.
For long term frost the only answer is to add some heat, no matter how small.

 

I rather agree with Pete - continuous frost will eventually get through a fleece.

I think fleece on a plant acts rather differently from normal insulation. A human body generates heat. And if you wear clothes they slow down the loss of heat, so that you always have a temperature gradient across the garment. But a plant doesn't generate any heat. So after a while the temperature inside and out will be the same.

I suspect that a major benefit of a fleece is that it keeps the wind out. It always feels warmer if you are out of the wind even though the temperature itself may be the same. There is a good reason for this which is to do with reduced moisture loss. For that reason I suspect that it may not be as effective inside a polytunnel, where the air is pretty still anyway.

But it must have some effect at slowing down the penetration of cold by slowing down air movement. Which makes me think that two thin layers would be more effective than one thick one.

If its any consolation, the 17 gsm product was originally produced by ICI and made for disposable panties - but the botttom fell out of that market. The thought might warm up your plants a bit. :D

 

...bottoms falling out of disposable panties...no wonder that market ceased :wink:

 

I bought the thickest. You can double up to provide more protection, but its more faffing about, and more chance of the flimsy material getting blown off the plants.

But my main reason was that I had read that the flimsy stuff rips easily, and therefore you tend to have to replace it sooner. If you are protecting plants in a polytunnel that's probably not much of an issue, but the stuff I use is for outside and I don't put a lot of effort into looking after it well! Out on a chilly night, quick-as-a-fox pull it over the plants, chuck some logs on to weight it down - probably tug it, cursing, from whatever it gets caught on ... had it three years now and its still in good shape.

 

We've "tree cosies" for our patio trees, orange, lemon and olive. But the tree cosies didn't save the orange and lemon last year. If we get another spell of such cold weather, I'll put them in the rabbit shed. We did get some frost damage on a few azaleas and a rhodo, but I've some fleece left over from what I bought to put under the bubblewrap around the big patio pots, so I'll lay that over them if necessary.

I don't expect this again.

 

It looks like it's going to freeze tonight, so I've just been out and put on the tree cosies and some fleece on one or two things.

 

Same here DR. Went out and bought some today. I am trying to protect what I have done so far. I would be absolutely gutted to lose plants just because I didn't follow good avice.

Although it was frosty last night, it was zero degrees in the tunnel this morning. By 11.00hrs, it was a very cosy 19 degrees in the tunnel.

Chopper.

 

Hi,
So with pots i was told to stand em on feet things to keep em off the ground. Is this best for my acer or would i be better sitting it on polystyrene?

Cheers
D