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44 WINES&VINES January 2016 GRAPEGROWING ers in cooler climates may also get the added benefit of enhanced early season growth from the greenhouse-like growing environment cre- ated by the plastic or cardboard tube. However, it is this greenh ouse effect that can lead to issues in the winter months if the grow tube is not removed in the fall. Grow tubes left on young vines over the winter will cause the air immediately sur- rounding the young trunk and graft to heat up during a sunny day. Those warm temperatures may de-acclimate vines and, if followed by cold evening temperatures, can lead to damage of the trunk tissues. ADVICE: Remove those protective tubes in the fall, by the time of the first hard freeze. This allows vines to gradually acclimate to winter temperatures and reduces the occurrence of premature deacclimation. 5 The indiscriminate weed whacker Uncontrolled weeds that grow into the canopy can be a big problem for young vines. Weeds compete so well that even water- ing and fertilizing young vines is not enough to compensate. It can be tempting (and physi- cally satisfying) to run into the vineyard with a weed whacker. But no matter how careful one tries to be, the end result is always a few scuffed trunks or denuded graft unions. The physical damage may heal fast, but the bigger problem is a gall-forming bacteria called "crown gall." These bacteria are often found in a quiescent state in the trunk tissue of vines and are stimulated by injury to the vine trunk or cordon. Crown gall can lead to death of the vine if found below the graft union and may weaken what could otherwise be a strong vine. Crown gall is usually associated with damage from cold weather, but even in the warm south the occasional human-induced injury can have the same effect. ADVICE: Keep the weed whacker for your lawn or fence line, and out of the vineyard. 6 Not reading product labels This issue tends to come up with the "weekend warrior" grower. It is indeed possible for a part-time grower to have a day job during the week and still manage a productive vineyard. However, a new grower has a lot of reading to do before they can just jump out of their vehicle on a Friday evening and start working on their vines. It is easy to glance over the label of a pesticide too quickly, which can lead to problems with improper measurement, inade- quate use of personal protective equipment or mixing of incompatible products in the same spray tank (e.g., sulfur should never be mixed with oils). As an advisor it is tempting to provide the quick answer for a mixing rate for a product, but I try to encourage new growers to read the label and learn how to find the answers. All growers should learn to identify the pre-har- vest interval (PHI), restricted entry interval (REI), maximum rate per acre per application and per year, and required personal protection equipment (PPE) on the label of any product used in their vineyard before mixing and ap- plying that product. ADVICE: Learn how to find the most important safety and regulatory information on product labels. Highlight it and train your crew accord- ingly. Remember, the label is the law, and knowing what is on it will protect both you and your vines from harm. 7 Too much of a good thing If a little is good, then a little more must be better, right? New growers learn over time about the importance of a concept known as "vine balance." Vine balance, in short, is de- fined as a vine that is growing in equilibrium with its environment at a steady and productive pace. A balanced vine will have a ratio of fruit- to-leaf area that falls within a range that allows the fruit to ripen to the quality level desired without overstressing or over-cropping the vine. The concept of balance is subjective in many cases but also can be measured using a simple index of fruit weight to dormant cane weight, known to viticulturists as the "Ravaz Index." The most common mistake a new grower can make with young vines is to apply an excessive amount of fertilizer. Too much fertilizer not only wastes money, it can pollute groundwater, accumulate in soil to cause root burn or leaf burn, or induce high-vigor growth of poor qual- ity wood for trunk and cordon development. Growers should also be cautious about apply- ing foliar fertilizers too frequently to avoid burning leaf, flower or fruit tissue. ADVICE: Approach vineyard fertilization with balance in mind. Use the results of soil and plant analysis as a guide for precision fertil- izing, adding only what is needed and when vines need it. Be careful not to spray high con- centrations of fertilizers on foliage. If you are new to grapegrowing, I hope the above examples can help you to avoid com- mon mistakes with your new vineyard. If you have been growing grapes for a few years, I would challenge you to find a common mistake that you have not already learned the hard way. I certainly have, and I would say that there is no better way to learn than by personal experience. Fritz Westover is a viticulturist and owner of Westover Viticulture, based in Houston, Texas. He specializes in vineyard consult- ing, research and education in the south and southeastern United States. Westo- ver is a contributor to Wines & Vines, and he maintains a practical grapegrowing blog and grower resources at vineyard- advising.com. A crown gall lesion caused by the bacterial patho- gen Agrobacterium vitis may be initiated by winter cold damage or physical damage with equipment. This first-year vineyard was successfully established in Weimar, Texas. A balanced vine will have a ratio of fruit-to-leaf area that falls within a range that allows the fruit to ripen to the quality level desired.