Are potato grow bags frost proof?

[selfraising]

Hi I have bought some potato grow bags to put some of my first earlies in. They are made of thick plastic. I was just wondering, if we get a frost, would I need to wrap the whole bag in fleece or just cover the top?

[HeyWayne]

As I understand it, it's the foliage you need to protect from frost. It's that which stops the tubers growing well. It's the main reason for "earthing up" spuds I think.

[selfraising]

Thanks HeyWayne, I was just worried if the frost penetrated the grow bag, the spuds might rot cos I already lost a few whilst chitting that were caught by frost in the shed.

[HeyWayne]

Thanks HeyWayne, I was just worried if the frost penetrated the grow bag, the spuds might rot cos I already lost a few whilst chitting that were caught by frost in the shed.

Not quite sure how it works, but I think it's something to do with ice crystals forming in the plant structure and causing damage to cells etc. Quite why it effects some plants and not others is beyond me.

[Eyren]

I think if you are planting them in compost, the compost itself should act as an insulating blanket as long as it's not too damp (see Tattieman's excellent threads in Growing Techniques for watering tips). If you are standing them on a hard surface like a patio, it might be a good idea to raise them off the ground slightly on something insulating like a sheet of big bubblewrap or folded newspapers if frosts threaten, to protect any roots that have grown downwards - I planted mine yesterday so I'm not expecting to see any shoots above the surface for about a month, based on previous experience.

[selfraising]

Thanks Eyren and thank you for the tip about raising them up, as they are on patio slabs at the moment,so will do that today!

[Two_Sheds]

Well, my plastic greenhouse isn't frost free, so your grow bag won't be.
I think you should wait a bit, personally.

[aylithuk]

well I've had my 3 early seed potatoes in for about 2 weeks now in one of those grow sack thingys (One I got from Mr Tattieman)

I have put the grow bag into 2 x Fleece sacks and I've not seen any harm come to them as yet. In fact I went out this morning and saw 2 of them had starting sprouting out the compost.