Define 'large bin' Treepot. The grape vine has a long tap root which in pushes down into the soil.

Its a plastic dustbin the size we used to use before wheelie bins.

Grapes in containers are not a great idea. It nearly always comes down to watering.

Remember that water moves through the soil (open ground) like blotting paper and is a much more equitable environment for roots, especially temperamental roots such as grapes. In containers, especially if planted in such large ones, water remains static and indeed can keep the planting medium too moist causing root rot. The number of customers that I have had with grapes failing in containers......

You need to move grapes up in stages so that the roots don't have a huge body of soil/compost around them they they take and age to get their roots into. Because of the nature of the plant (climber), this is not really practical.

Can you plant them in the ground?

I can plant them in the ground, do they have any special needs?
When is the best time to move them??
Thanks for your reply

I would probably leave them until autumn or very late summer at the earliest and move them then. Let them dry out more between watering until then but when you do water, give them a good soak (one 2 gallon watering can should be adequate).

When you do plant them in their new site (later this year), add a little bonemeal to the backfill soil. This is rich in phosphates and encourages health root growth. It also contains Nitrogen which is released slower over a longer period but this is good for health shoot and leaf growth. Make the backfill soil be a good quality topsoil mixed with a little multi-purpose and that's it!

The next season, only give the occasional good soak no more than once a week in very dry weather. You can mulch around their base with something like composted bark to help retain moisture over a longer period. Any pruning (something I suspect you have not needed to do yet!) should never be done in spring, especially just before bud burst as they "bleed" and this weakens the plant. Keep major structural pruning to the middle of winter and light pruning to summer/autumn.

Thanks so much Fractal, thats great