Budburst is truly one of the most exciting times in the vineyard and I love watching the growth and development. Grapevines are hermaphrodites, which means they have both male and female reproductive organs, so they can self-fertilize. In short, they don’t need bees to make grapes… At this stage, the biggest risk in the vineyard is spring frost but with the temperature in California well above 70o F (+20oC), I think we’re in the clear and now it’s time to focus on vine balance.

I’m obsessed with this concept as it’s the scientific approach to viticulture (growing wine grapes). Basically, we talk about the “source”, which is how much nutrients the vines receive, and the “sink” is what the vine does with the nutrients. We want a balance between the “source” and the “sink”. To manage the “source”, we can either increase or reduce the nutrients such as water or fertilizers. In our vineyard, we have clay-heavy soil that retains water and nutrients, so we actually want to reduce the “source”. This year, we’re using more cover crops between the rows (see photo) to reduce the “source” for the vines. For the “sink” there are two ways the vine will use the energy/nutrients: (1) vegetative growth (shoots) or (2) reproductive growth (grapes). We want the vines to focus on reproductive growth but with enough vegetative growth to actually ripen the grapes. At this stage in the growing season, we go through the vineyard and try to determine how many shots to leave on each vine. It’s really really difficult and the only experience will tell you what to do. If you remove too many shoots, the vine will focus on vegetative growth. If you leave too many shoots, the grapes may not ripen fully. If we leave too many shots, we may also run the risk of too dense a canopy, and then we have mildew problems.

Contrary to common belief, we actually want to optimize the amount of fruit on each vine and not reduce it. Some producers argue small yield per hectare equals better quality fruit. Research has shown that is not always the case. For example, Syrah (which we grow) has greater quality with higher yields. That is the same for Cabernet Sauvignon and Chardonnay, but not the case for Pinot Noir. Of course, there is a balance, but we actually want higher yields from our vineyard. In the next weeks, we’ll continue monitoring the vegetative growth and prune, if we need to.