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s mGaRrAt P E G t iOcW Il N u r e vi R u tG haps up to 30 buds per cane, and canes five feet long, to fill the gap on the wire caused by the missing vine. This is quite unsatisfactory and would cause problems of extra cost and difficulty at winter pruning. The double-header system offers a solution. Rather than by having a single head just above the trunk, convert to two heads, each located about the end of the existing vine canes. Conversion at winter pruning is simple. Rather than cutting off the old cane, lay down two new canes from the end of the existing two-year-old cane. One cane is trained back toward the trunk, and the other into the gap caused by vine removal. Both canes will be around 2.5 feet long, with about 12 buds, as usual. But the vine will now have four canes, not two, so the bud number will be doubled. This will satisfy both Golden Rules. Success with the double-header system The yield is much improved with the double-header system, and canopy shad- ing reduced (see Figure 1). The yield is 3.5 tons per acre, but this was after each shoot was thinned to one cluster, which Bennett believes is necessary for premium quality. Bennett and his winemaker find that the double-header vines now give the best quality, as opposed to the worst previously. The wine judges agree; the Bennetts often win trophies at Australian and international shows, including the best 2005 Pinot Noir wine at the Tri Nations Wine Challenge (Australia, South Africa and New Zealand). Installing the system I would suggest that to make the new heads tidy, install a new fruiting wire about six inches above the existing one, unwrap the old canes in the first year of training and put them on the fruiting wire, remembering to keep the previous (two-year-old) cane below the wire. Bennett is planting new vineyards with vine spacing to use double headers from the beginning. He also amazed me by showing mature vines just starting bud break, while other young vines were ready for harvest. Bennett had planted some vines he had previously removed, and conserved in a cool store. They had a small root mass but were able to regrow! Conclusion The double-header system is a great development for vertically trained vines. Of course it could also be used to create Scott Henry trellis vines, which would be an extra tool to control vigor. Bennett reminded me that cane-pruned, horizontally divided canopies have long used double-header system. I have seen such examples with both Lyre and GDC trellises. PWV Dr. Richard Smart is rewriting and thoroughly revising Sunlight into Wine. He is happy to receive statements from growers and winemakers about their commercial success with various aspects of canopy management. Interested persons should contact Dr. Smart by email at richard@smartvit.com.au. Dr. Smart visits the U.S. frequently, and consulting appointments can be made by email. See also www.smartvit.com.au. When you need regulatory guidance or licensing assistance anywhere in the USA Trust the experts COMPLIANCE SERVICE of AMERICA www.csa-compliance.com 70 p r acti c al w i ne ry & v i n e yard J U LY 20 13 800-400-1353