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Stories from the valley

Harvest is on the horizon but water still on our minds

Contributed by Tim Johnson

This is the time of year when we start thinking seriously about harvest. The grapes are starting to change from hard and green to softer and purple (for red varieties), in a process called veraison. From here it’s about 45 days until harvest – our best time of year! With harvest on its way you wouldn’t necessarily think we would be focused on irrigation but we are.

This time of year, irrigation is critical. From the mundane to the artful, we think about water now more than at any time in the year.

First, the mundane – voles (think of a field mouse, only cuter) and other wildlife just love to chew drip lines. We cruise the blocks twice a day to make sure the drip system is in perfect operating condition. That means repairing the places where voles have chewed through to get a drink or just to chew. It also means replacing drippers that are clogged or may have sediment in the diaphragm of the emitter causing them to put out too much water. Not bad work on a hot summer night.

The art comes into play managing water to ensure even ripening and high quality fruit for the wineries. The trick is to give the vine just enough water to mature the crop but not so little that the vine starts to go dormant and drop its leaves. This practice is called deficit irrigation.

Next week we begin taking sugar readings for the white varieties – chardonnay and riesling. It is these readings along with our titratable acid measurements that will tell us how the bunches are maturing. Closely following soil moisture and observation of the vines will tell us how they are doing.

Ann will then balance bunch maturity and vine stress turning on the irrigation only when she feels the vines must have more water or that the bunches need more hang time to ripen.

This time of year, it is all about water.