A.E. Nightingale, Ph.D.
Texas A&M University
Location: Messina Hof Vineyards – Bryan, Texas
TREATMENTS: 1 ounce of Spray-N-Grow/gallon of water Applied as a spray to thoroughly wet foliage
First: new growth showing
Second: cap drop
Third: 30 days later
Chenin Blanc and LeNoir
On dates determined by the grower for harvest, ten representative plants of both treated and untreated blocks were randomly selected for harvest data. Plants were tagged, harvested by hand and placed in separate containers. The bunches from each plant were counted and weighed. Ten berries from each sample were picked at random and submitted for chemical analysis.
Due to the number of plants available, only five plants of the Cabernet Sauvignon were sampled from each block.
CHENIN BLANC Treated
Lbs per plant: 11.22 (+1.54)
Clusters per plant: 29.9 (-3.8)
Brix: 19.0 (-0.8)
pH: 3.36 (+0.02)
Titratable Acidity: 1.07 (-0.04)
CHENIN BLANC Control
Lbs per plant: 9.68
Clusters per plant: 33.7
Titratable Acidity: 1.11
CABERNET SAUVIGNON Treated
Lbs per plant: 10.85 (+4.15)
Clusters per plant: 42.4 (+15)
Brix: 21.7 (-0.02)
pH: 3.20 (-0.07)
Titratable Acidity: 1.07 (+0.07)
CABERNET SAUVIGNON Control
Lbs per plant: 6.70
Clusters per plant: 27.4
Titratable Acidity: 1.0
Lbs per plant: 14.45 (+5.85)
Clusters per plant: 33.6 (+10.7)
Brix: 23.7 (-0.9) pH: 3.50 (-0.08)
Titratable Acidity: 0.74 (+0.02)
Lbs per plant: 8.60
Clusters per plant: 22.9
Titratable Acidity: .72
Data was subjected to an analysis of variance. The yields of treated plants of LeNoir were highly significant at the .01% level over the control, and the Cabernet Sauvignon yields from treated plants were significant at the .05% level. Chenin Blanc yields were about the same statistically. Comparison of the raw data indicated observable differences between treated and untreated plants for both cluster size and yield:
30% increase in cluster size – 16% more pounds per plant
33% increase in cluster size – 56% more pounds per plant
13% increase in cluster size – 68% more pounds per plant
The chemical analysis showed that there was no effect on the brix, pH, or the titratable acidity. Over-cropping can, in some cases stress a plant so it can not produce enough sugar and end up peaking too soon.
The results of this trial were very important to the grower in that the increase in yield did not adversely affect the chemistry of the fruit.
In general, the treated vines appeared to have better growth and appearance. The positive results of this trial indicate that the use of this product was beneficial and that further testing should be conducted.