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s mGaRrAt P E G t iOcW Il N u r e vi R u tG shoot density and hence shading, and so we will change one problem for another: excessive vigor for excessive shading. The second Golden Rule is that shading is reduced with less than 15 shoots per meter of canopy length, or about four shoots per linear foot. The obvious solution is to leave more buds on the vine, but to increase canopy length so as not to increase shoot density. This is quite simply done by removing every other vine in the row, and potential bud number can be more or less doubled but shoot density not changed. This transformation can be achieved in one year by modifying the winter pruning practice. The solution is very simple in warm to hot climates, where spur-pruning is commonly practiced. One merely extends the cordon to fill the gap of the missing vine, which can normally be done in one year. In cool climates, this solution is not so simple. Spur-pruning is generally found unsatisfactory because the fertility of basal bud positions is low. The clusters are typically small and few in number. For many varieties, it is not satisfactory to spur-prune in cool climates. The answer is cane pruning, so bud break can be promoted at higher bud positions Figure 2. Terry Bennett stands next to a double header-trained vine (note trunks and extended cordons). on the cane. This results in a larger number of heavier clusters. Introducing the double-header system This is where the double-header vinetraining system comes into play. Imagine the normal cane-pruning system on fivefoot vine spacing in the row, with two canes around 2.5 feet (maybe 12 buds) trained each way from the head. Removing the in-between vines would mean that the number of buds per cane would need to be at least double, per- 3556 Sankey Rd Pleasant Grove CA 95668 | www.calspl.com pr actica l win ery & vin e ya rd JU LY 20 13 69