Mowing and tilling and cover crops

White Rock Vineyards- organically farmed in Napa Valley. April 2010

Ever wonder why some vineyards mow the cover crops in their rows so closely in Spring? Or why some don't? Or only mow every other row? Or why some vineyards don't appear to have cover crops at all? Since moving to a wine-growing area, these are the types of questions that pop up in my head on a regular basis. 

The answer to the first question is well-covered in the blog for Amapola Creek Vineyards in Sonoma Valley. Their post last month on flail mowing in the vineyards does a great job in explaining how the mowing of cover crops in the rows just before bud break reduces the vines' competition for water. Their vineyards are organically farmed so the root network tends to be more spread out beneath the surface, and the cover crops can more easily affect their access to water. The mowed crops can also be a natural fertilizer. Furthermore mowing the cover crops closely in Spring can protect the vines from spring frost by allowing cold air to circulate near the ground rather than around the vine.

As to why every other row may contain a longer cover crop- the answers could be from providing space in the alternate rows to toss vines during winter pruning. They could then be mulched to provide nutrients to the soil. A good explanation of this process can be found at the StillwaterVineyards blog. It could also be a matter of two different cover cropping systems on alternate rows.

More and more vineyards are converting over to cover crops and minimal tilling of the soil as vineyard practices become more sustainable. Tilling reduces the vine’s competition for water and nutrients, and helps a new vineyard establish its roots. On the flipside it affects the structure of the soil and intervenes in the ecosystem of the vineyard.  Most of the vineyards that I see in the Sta. Rita Hills and Santa Ynez Valley are using a system of cover crops, although I saw a newly tilled vineyard the other day that piqued my thoughts on the subject.

I’ve highlighted links to information that I found useful. I’m just scratching the surface in the most general terms- I encourage any comments and/or clarifications. This is one of those subjects where questions and information begets more questions… Cheers!

Vertical or horizontal?

Horizontal rows at Storybook Mountain, Calistoga, Napa Valley

Have you ever wondered why some hillside vineyards have horizontal rows while others have vertical rows?

Working at Arcadian's tasting room today, I got into a discussion with guests about the varying exposures of slopes in vineyards and the possible influences on the resulting wines. The conversation eventually led to me being asked about the reasoning for horizontal or vertical rows on the slopes.

It was one of those moments... you've learned it before and you're aware of the answer. However it's something you don't think about everyday so the brain put the breaks on verbalizing an answer. Otherwise known as your mind going blank. My answer was based around vertical and horizontal rows offering different sun exposure to the vines; and also the possibility of the direction of the rows affecting the overall use of the land. My answers were correct in a very general sense, but I didn't feel on top of my game in giving the answer.

So to be more exact, the reasoning can be based on factors relating to the land, ability to work the land, exposure to the sun, and even to reasons related to culture and tradition. In general -- horizontal rows are easier to work, either by hand or by machine. A steep vineyard would require horizontal terraced rows just to be able to be tended. It would also require the horizontal rows to help in maintaining the structure of the soil. Conversely, vertical rows may increase exposure to the sun. This may be important in a cooler growing area where the grapes may need the extra sunlight to reach the desired ripeness. I live near the cool-climate Sta. Rita Hills AVA in Santa Barbara County and drive through the AVA a few times each week. The hillside vineyard blocks here are predominately planted in vertical rows, thus prompting the question from the guest.

Wine is such a humbling subject. There's so much information and knowledge, you're always just a question away from having you're mind go fuzzy on you. I wrote this post to clarify my thoughts on the matter... any further thoughts or clarifications are welcome!

Vertical rows in Sta. Rita Hills