# How far apart should rafters be spaces on pergola if used specifically for the purpose of growing grapevines?

Im planning on training 2 grapevines to grow ontop a pergola but im a little confused as to far they'll span (shoots) without dropping so that i can space my rafters accordingly. Plus, do i need slats ontop the rafters? If yes then again, how far should they be spaced? And should the vines run parallel or perpendicular to the rafters?

For the last question: the usual method is one year parallel, and one year perpendicular (because it is the direction it will take naturally: new branches perpendicular to previous branches).

About the distances: they are vines, they can reach few meters distance without problem (but with risk some go down, and so you need to move them up). For real distances, you need to estimate static load. Calculate few kilograms per square meter on center (where you will have most o grapes), and estimate winds. I would have some kind of rafters, or lines every 50 to 100 cm. On my place, we usually prefer larger (and more distant) rafters with some wires between them (but I think mostly because of snow). You can use thinner rafters, but do not forget that plants (any plant) will weight much (and grape vine produce grapes: very watery, so also heavy).

• Should the rafters run parallel or perpendicular to the sun? Commented Feb 20, 2019 at 17:45
• For grape vines, do not matter. Choose for aestatics Commented Feb 20, 2019 at 18:47

I've trained a vine (cultivar - Phoenix) up a pergola in my garden, so I can tell you what works for me. There's a permanent "T" shaped framework consisting of a single main stem going up one vertical face of the pergola, which divides into two horizontal arms perpendicular to the roof batons and tied in at the top. The roof batons are 450mm apart. Each year I let one new shoot grow along each baton, tying them in as necessary and removing all side shoots. These are the fruiting canes. Each winter I prune these back to a couple of buds of the horizontal "T".

• @peter4075_ thank you for sharing that. So you mean to say that you let the vine grow on top one of the side posts until it reaches the middle of the side beams and then train it all the way across to the other side of the pergola where two branches grow across the opposite side beams and thus forming a "T"? Commented Mar 22, 2019 at 20:57
• Btw, how big is your pergola and do you have just a single vine trained ontop of it? Commented Mar 22, 2019 at 20:58
• @HamidSabir - Sorry, should have been clearer. It's a really basic four post pergola with a single vine. The end face (vertical posts 1750mm apart) of the pergola is trellised, so the main vertical stem grows up the centre of the trellis, ie equidistant from the end face corner posts. The important thing to note is that you need to prune the vine to a permanent framework to allow each season's new canes to be trained along the roof battens (aka rafters). Vines are vigorous, so you need to be ruthless in removing unwanted growth. Hope that helps. Commented Mar 23, 2019 at 9:08
• If you want to train the vine up a corner post, do that and then have a permanent horizontal arm along the top of the pergola to allow the new season's growth to be trained along the rafters. Each winter, cut these fruiting canes back to one or two buds from the permanent horizontal arm. Hope that makes sense. Commented Mar 23, 2019 at 9:11