confused about horticultural fleece - help please!

Hi,

Just been on eby hoping to buy some horticultural fleece until i realised it comes in different 'types'!!
It seems that it is measured in gsm (which i assume is the thickness) but i have no idea what thickness i need! I am buying it to wrap around the trunk of my Acer palmatm (its only a fairly young tree in a pot) and i will prob use some around some other plant pots.

Can anyone tell me what i need please?

many thanks

 

Busybee - you can buy a range at your local garden centre, where you can see them and feel them. I wouldn't bother to buy them off eBay, unless I wanted to buy a massive quantity at wholesale prices.

You need to understand how it works. If you stand in a cold wind in the winter it feels cold, if you move out of the wind by going round a corner it feels warmer. Actually the temperature of the wind is exactly the same in both cases, but in the first case there is a chill factor caused by the evaporation of moisture, which makes it feel colder. Fleece acts in the same way. The actual temperature will be the same in both cases, but the fleece produces an area of still or slow moving air which feels warmer to the plant. It combats the wind, rather than combatting the cold. Consequently if you use it inside a greenhouse it will have virtually no effect, if there isn't any wind to start with.

So the thickness you need should be enough to slow the wind. Once you have done that extra layers will do nothing. So you don't need a very thick piece. I can't remember ever seeing the weights displayed at a garden centre. But you are right - gsm means grams per square metre. The thinest material is 40gsm and this is usually used as a fleece. The thicker materials tend to be used where their strength is needed, as weed supressant material etc. The original material at 140 gsm, was used under motorways, rather than for gardening!

It works where there is moisture that could evaporate - ie with plants. But it will do nothing around the ceramic or plastic pot itself. You should use bubble wrap for that.

 

Peter, you know me, I hate to disagree but, I'm sure a thicker fleece would be a better insulator than a thinner one.
In fact I'm trying to find some real heavy stuff to use instead of blankets, that I've used as frost protection up to now.

I need a flexible material that doesn't absorb water but is a good insulator.

 

Heavier fleeces last longer and can be used for several years

Lighter fleeces rip quite easily and may not even last a season

Pay your money and take your choice

 

Pete - I agree that a heavier material would be a better insulator. Perhaps I am just being pedantic. I was trying to distinguish between a fleece and an insulator. To me fleece generally means thin material that just reduces air movement around the plant. But doesn't actually insulate - ie the temperature inside the fleece and outside will be the same, but the plant will still benefit from the still air. I see thicker materials as insulators - the sort of stuff where you can have a different temperature inside from out, in the way that our clothes operate.

It depends on what sort of plants we are talking about. Just a thin sheet that will stop the air movement is often sufficient for borderline hardy plants. I use it over a Salvia microphylla. But for tender plants - the sort that really should be under glass you need good thick insulation, and the thicker the better. I don't think garden centres usually sell thick insulating material - though you could always use the stuff they sell for capilliary matting.

 

I don't have any really tender plants, only the 'boderline' type Peter refers to - and, granted, not many of those - so (because these plants are still relatively small), I tend not to use fleece but rather I push 4 sticks in the ground around the plants and make a 'tent' using bubblewrap and 'bulldog' clips.

 

Ok Peter, I think were looking at the same thing in a different way.

Fidgetsmum said, " make a 'tent' using bubblewrap and 'bulldog' clips",.
Now rust proof bulldog clips would be a real help.
Clothes pegs are not so good.:(

 

Well thank you all so much for the advice. PeterS your explanation helped me to understand and Pete cleared a few things up. Fidgetsmum i like the idea of making a tent over the tender/borderline plants cos i get that is ueful for smaller plants that are best left in-situ rather than potted up and taken indoors/greenhouse.

Thank you all so much, i will head down to my local GC for a look!!