Petiole analysis is generally considered the best means of determining the nutrient status of grapevines and is needed to help make fertilization decisions for the coming year. Soil analysis alone does not give a good indication of the vine's nutritional status, but is helpful in making fertilization recommendations when a petiole test is also done. Petiole analysis should be done at least every other year. Where high rates of fertilizers have been applied within the past year or two, it is advisable to test yearly to monitor progress and to determine if further adjustments are necessary. Soil analysis is recommended for most situations, since an assessment of nitrogen may be better determined by other means.

The processing time is variable, depending upon the time of year, the number of samples being submitted by others, etc. In general, however, growers who submit "No Nitrogen" petiole samples should receive results in about four to six weeks.

KEEP RECORDS

Give each sample a REFERENCE NUMBER and record this number in the following locations:

     - in your records

     - on the information sheets

     - on the bag in which you will collect the sample. If soil tests are also taken, be sure both the petiole test and the soil test numbers are recorded on both the petiole information sheet and the soil information sheet.

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