irrigation

The most important input or resource we have to manage is our water.

No surprise to most people, water is and always has been a scarce and valuable resource in California. Given our steep, shallow and rocky soils, relatively little water is held in the ground to support our vines through the long growing season. Consequently, irrigation is required. Our challenge is to use our water judiciously, restraining vegetative (green) growth so as to produce just enough grapevine canopy to ripen our grapes and keep the vines healthy.    

Typically we begin irrigating in June and water the vines regularly through the harvest in early to mid October. We carefully monitor vine growth in the spring as the vines deplete the ground water left over from winter rains. At their peak each spring, the vine shoots can grow up to an inch a day with ample water and sunshine. By monitoring this growth carefully, we can see the shoot growth slow week to week in late Spring as the ground water is depleted. We begin irrigating only when we see that water is needed to sustain healthy vine growth, without which we would not have enough leaves to ripen the grapes.

Once we begin irrigating in the Spring, we dole out the water in small doses, typically 3 times a week.   With short, shallow irrigations we have a smaller margin for error (and tolerance for missed irrigations), but avoid wasting water due to sub-surface drainage on our quite-steep vineyard. Each week we calculate the water to be applied using an evapotranspiration model, accounting for the effects of weather and overall canopy size on water needs of the vines. No surprises here. Bigger vines with more leaves (e.g., August vines are bigger than the same vines in June) need more water, and all vines need more water during hot sunny weather. Water is through our drip irrigation using programmable electronic controllers, set according to the aforementioned calculations for that week.

Specific practices in grapevine nutrition, pest management, and weed control continue here