Support for a single grapevine
I would like to plant a grapevine on my allotment, probably the Fragola variety. I read that you should leave 1.2 m between plants in a row, but as I only want to plant one, does it mean that it only needs supports 60 cm on either side? I'm planning to use three posts, one to support the plant itself and two on the sides, so as to be able to attach the supporting wires to them. But 60 cm seems like a very short distance. What would you suggest?
How much space should I leave in the other direction, between the grape vine and the next row of plants?
Also, what kind of shade is the plant going to cast? Dappled shade? If I plant lavender about 60 cm from it on the east side (the grape vine is going to grow in the north-south direction), would that be too close?