Hi Neil and welcome to GoY your vine needs to be planted in the ground not a pot. They have a large root structure and confining it to a post will not be conducive to it doing well.

Some people swear by planting the vine outside the greenhouse and bringing the stem inside through a hole. Don't ask me how - maybe this is in greenhouses with brick walls at the base. Its also said that a good thing to do is to bury a dad dog under the plant, but this isn't always easy.Especially if you grow the vine in a pot. Probably some nice fertiizer would do the job instead!

Have a look at this link which has some useful info including pot cultivation and recommended varieties.

http://www.gonegardening.com/xq/ASP/group_id.20/article_id.323/referer./qx/gg_shop/article.htm

Our vine used to have its roots outside the greenhouse and the actual vine inside... worked beautifully until we had to move the greenhouse. Vines do not need a huge amount of fertiliser there natural growing conditions are lean and mean.

A dad dog??? I meant a dead dog. :))) MG, perhaps it might be thought mean to bury a dead dog there... at least it would be slow release!

We bury our dead cats in the garden and plant things on top of them...

I'm just wondering what vine it is that you would like to grow?

I would assume a grape vine.

Most likely MG I agree, but to "assume" makes an "ass" of "u" and "me"!!

Excellent, Meanie ! Never seen that before.

One of the first things that I was told as an apprentice! Have recalled it pretty much every day of my working life.

As 'meanie' says, what is the vine you are thinking of? It definitely depends on the type of vine, and also I would add the size of the greenhouse, as a grape vine would cause huge problems with getting in the glass frames etc. The control of it, whilst encouraging flower and fruit, could be a problem. A grape vine needs warmth at its base and light for the vine/leaves and will not produce grapes until the growth of the vine is stopped - like a wisteria. Other vines like passion fruit might be better. And honeysuckle could just take over, unless frequently pruned out of the window frames etc. Also, grapes need minerals and water (when fruiting) but not alot of nitrogen/mulch based stuff. MG suggests they are huge feeders but "natural growing conditions are mean and lean". It cannot be both! I go with my italian heritage that suggests more minerals such as potassium and calcium, and less nitrogen based feeds.

Excuse me MG states clearly that grape vines are NOT huge feeders...they need lean and mean growing! You guys go ahead and sort this out...

Moon Growe is totally right - I have sent her an apology, and must do the same for you, Neil, and hope I haven't confused you too much. Best wishes.

Oh and Meanie if we made no assumptions on this site a good percentage of the questions would never get answered.

Ha ha, ain't that the truth, Moon Grower...

Yup it is Bamboo, we do our best to answer questions that have less than the desired amount of info in them...