Watering spikes

[Kirsty_84]

Does anyone have any recommendations for watering spikes?

I've just tried using some that I got from RHS Tatton last year and I'm not convinced they'll see my plants through my two week hols (tho' it says on the packet that it will). They're the kind that water according to the weather and I was surprised that they DO work - the one in shade released less than the one in the sun - but a 2 litre bottle isn't big enough, surely?

[womble]

I expect if you have a plant outside in the soil and it rains a bit while you are away, the weather is overcast and not hot, 2 litres would be enough.
If the plant is in a greenhouse and it is hot, it's going to be dead when you get home.