Manton and the surrounding area are at an elevation of 2,700 ft., the winter and spring months tend to bring extremely cold weather to include hail, frost and snow. It is difficult to grow grapes in the region.  We decided to conduct an experiment to determine the best possible method of protecting the grapes during the winter months.  Due to the fact that we are limited in our water supply we decided to try and utilize the Wade Rain Pulsator to keep the frost from damaging the vines. In the past it has been necessary to keep the equipment going for the three weeks without turning it off to protect the vineyard.

            We started the Pulsator Experiment in March of 1998, at the beginning of our growing season. The purpose of the experiment is to be able to frost protect our vineyards without consuming our water as rapidly as the conventional overhead irrigation. We are told that the Pulsator might be the answer since it uses between 15 to 30 gallons per acre per minute, versus the method already being used which uses 55 to 60 gallons per minute.  We rely on a series of fumes, ditches and reservoirs for our water needs. The amount of water used during the peak times can rapidly deplete out storage and put our crop in jeopardy.

           My associate, consultant and a former vineyard manager of the ranch Bill Faggard and I, first tested the Pulsator with a garden hose hookup.  We both had very little confidence in the unit prior to that test,  and did not believe at this point that the amount of  water put out by the Pulsator would be sufficient to protect the crops in an area such as ours.

            However, we had committed two ½ acre blocks of Chardonnay wine grapes to be used as an experimental area.  We installed the Pulsators in the lower end of the block and they were set for 3 gallons per hour, per unit.  The top of the block used the 6 gallons per hour units and the center of the block remained protected by the conventional overhead sprinklers.  The lowest temperatures recorded that season was 25°F.  (See graph 1) We have provided a graph showing the temperatures as they occurred. The equipment used is telemetry realtime weather monitoring devices, purchased from Automata.  There was no significant difference in crop loads or pruning weights between the 3 different blocks.  It must be noted that we installed sprinkler shields between the experimental and conventional fields to limit drift and inaccurate findings.

Photographs which are enclosed with this report indicate the three sections which the vineyard was divided and which was used for our experiment.  Photo #1 shows the bottom part of this experiment running with Pulsator sprinklers at 3 gph.  Photo #2 is the middle section, running with regular conventional sprinkler heads and Photo #3 shows the top section of  the block where used Pulsator sprinklers at 6 gph. Since we have had some of the worst damage in the past in t his area, we decided this would make a prime target for the experiment.

            We began the frost protection on March 19, 1999. We did not know what kind of frost we were up against that year.  The frost continued and even though there had not been any damage, the weather conditions got worse and we still needed to protect the vineyard each night using the overhead sprinklers, which ultimately would freeze and stop running.  The temperatures dropped to 21.5F on April 9, 1999. Enclosed in this report are photos showing the severity of the weather conditions. We had to keep the water on until the next day was at 42F. As the shoot growth begun, we saw some shriveled leaves, but when looking at the overhead section, you can see some of the same symptoms.  When we looked at the shoot growth on the top of the block there was no noticeable frost damage.

            As the photograph shows, at 6 gph the shoot growth was longer than in the other two sections. Later, during harvest we took fruit weights from that same section and found out the section had delivered beautiful bunches.

            We then picked out five vines at random from each section. Though the top fruit weight  was less than the two sections, we feel that  the top section was the best protected over-all. 

            We feel the Pulsators worked using less water than the conventional sprinklers and plan to add approximately 40 new additional acres of Chardonnay protected  with Pulsators

            Specifically:

                        Top:         5 vines, frost damage, fewer fruit, 3 tubs

                                        27 1/2; 36 1/2; 44 – 108 lbs.

                        Middle:    5 vines, 3 tubs, no pulsators

                                        50 ½; 41; 30 ½ - 122 lbs.

                        Bottom:    5 vines,  3  tubs, pulsators

                                         121 – 121 lbs.