Grapevine nutrition

In conventional farming, commercial fertilizers are applied liberally to crops.

When most people think about grapevine (or plant) nutrients, they think about applying fertilizers to feed the vines. We prefer to think in terms of feeding the soil so that the soil can nurture and feed the vines. As a result, we apply relatively little fertilizer directly to the vines. Rather, we focus on the entire floor of the vineyard to surround the vines with soil rich in microflora and nutrients.

Although we remove a significant amount of nutrients in the grape crop each year, we try to recycle as much of that year’s growth back into the vineyard as possible. All of the leaves and prunings from vines are mulched in place in the vineyard. This is an important way to recycle the plant nutrients that are taken up into the wood and leaves of the vines.

Cover Crop: We also maintain a permanent cover crop on the vineyard floor that is never tilled or plowed under. This cover crop is a mix of native grasses, as well as clovers, brome and fescue grasses we have seeded.

1. • The cover crop provides a renewable stream of organic matter and nutrients that feeds the soil and its microflora.
   

2. •The cover crop also prevents erosion on our steep slopes, and provides shade to the soil culture and reduces soil moisture loss during the hot summer months.
   

3. •The roots of the cover crop also help aerate the soil and break up the heavy clay.
   

Compost: To supplement this recycling of native vineyard nutrients, we also spread compost over the vineyard floor each fall after the harvest.

Typically we spread about 3 tons of compost per acre of vineyard, mostly scattered or broadcast on the vineyard floor. We may also apply some directly under the irrigation drip emitters, which helps enrich the soil where the vines will be feeding during the following summer irrigation season.

In some years we amend the compost with mineral supplements, such as lime, gypsum or potash. In the fall we may also broadcast other micro-nutrients such as sulfur, boron, copper and other rock powders along with granular humic acids to boost soil fertility. Our program of mineral amendments is determined by biannual analysis of soil samples, which provides a profile of the nutrients and organic matter in our vineyard.

We also apply a liquid fish fertilizer directly under the vines, through the drip irrigation system. We use a fertilizer made from byproduct of fish processing for human consumption. Though low in nutrients by chemical fertilizer standards  (NPK 2-3-0), it provides a rich stew of organic micronutrients and amino acids that provide a bio-stimulant to the vines and soil microflora alike. We apply 10-15 gallons per acre each season, first in the spring shortly after budbreak, again after bloom and fruit set in the summer, and sometimes a 3rd application after harvest in the fall. We generally amend the hydrolyzed fish with liquid humic acids  and a soil penetrant derived from yucca plants with enzyme and mineral supplements.

Specific practices in irrigation, pest management, and weed control continue here