Unfortunately, we are going to grow grapes this year, again, in drought conditions. Current soil moisture levels, again, are well below historical averages, which means that ground water available for your vines is probably already very low, unless you already have started to irrigate your vines. Unless you know that your soils still have adequate water, most LWGA vineyards should consider commencing irrigation.

The youtube link below contains quite a bit of interesting information on soil moisture and makes the argument that insufficient soil moisture at bud break can negatively affect production and vine health for the entire growing season. The most interesting parts about soil moisture are near the end of this presentation.

Every vineyard has different soil depths and profiles and soil water retention abilities, so the following recommendations should be tailored to your experience to your soil water and irrigation needs. That said, for our vineyard, we have been using in ground soil moisture meters to determine when to irrigate and how much to irrigate. Following are my recommendations on irrigation for a drought year such as this year:

• If your vineyard had low production last year, it quite possibly was due to insufficient irrigation.
• First and foremost, look closely at your vines for signs of insufficient irrigation, such as tendrils that are flopping down or dried out. Also monitor for signs of excess irrigation. The LWGA website has previous presentations with visual guides for this.
• In a hot/drought year, your vines and landscaping will need more water. This may be 20 to 40 percent more water than a typical year.
• Start irrigation before bud break and as early as you see your cover crops beginning to turn yellow from lack of water
• Vines need more water as the growing season progresses. Increase the duration of your irrigation each month through harvest.
• Run extra irrigation before major heat waves, ideally 24 hours before high temperatures.

Very general heat wave suggestions:

• If temps will reach 95 degrees, give .2 to .35 gallons of extra water per foot of canopy length per day
• If temps will exceed 100 degrees, give .5 to .65 gallons of extra water per foot of canopy length per day
• Example: for 6 foot canopy length per vine, give 1 to 2 gallons/vine/day before 95 degree day, 2-4 gallons/vine/day before 100 degree day