Mulching my container garden: plastic bin liners, or wood chips?

[ddiogyn]

Now that my crops are becoming huge and beginning to bear baby fruit watering them is becoming a burden, with up to three times a day being required.

Everything is being grown in 12L B&Q buckets and at the moment the soil is exposed. Am thinking about applying a mulch in order to minimise water loss through evaporation from the soil surface, but which would be best? Plastic bin liners or wood chips (i've got several old bags of decorate wood chip...)?

[Two_Sheds]

I use newspapers, topped with a layer of soil to look tidy

[rustylady]

I use newspapers, topped with a layer of soil to look tidy

In pots????

[Two_Sheds]

Yes, in pots.