In episode 42 of the Vineyard Underground podcast, we had a Q&A session with Jim Duane from Inside Winemaking. We answered listener questions about topics like how to remove and replace dead vines, how far down you have to dig, and what natural pesticides we like to use. Below are just a few of the questions and condensed versions of our answers.
Q: Is it true that old vines produce fewer grapes, or is this a myth?
A: Old vines can produce fewer grapes. As vines get older, they may experience factors such as trunk diseases, root path issues, winter freeze damage, or reduced sap flow, which can lead to a decline in grape production. However, this decrease in grape quantity does not necessarily indicate a decline in quality. If old vines are healthy and well-maintained, they should still be able to produce a consistent crop year after year. The advantage of old vines is that they have years of experience, allowing winegrowers to make informed decisions during different weather conditions.
Q: How important is it to break through hard pan?
A: If hard pan, which is a layer of compacted soil, is impeding water movement and causing water accumulation, it can be detrimental to grapevines, as they do not thrive in consistently wet soil. Simply puncturing small holes or utilizing shallow cultivation methods may not effectively solve the problem. Instead, deep cultivation and ripping down to two or three feet can be more effective. However, this process can be expensive and not always necessary, especially if there is a natural slope present. A slope allows the water to continue moving downhill, albeit slower, instead of accumulating around the grapevines. Consulting a soil scientist who specializes in vineyards can provide a more accurate assessment and recommendation on whether breaking through hard pan is required.
Q: Is relatively more space better than less on any given site?
A: The appropriate vine spacing depends on various factors such as soil type, rooting depths, fertility, and management practices. In regions with heavy rainfall, growers may opt for closer spacing to allow for competition between vines and slow growth while maintaining a manageable cordon system. However, spacing too far apart can make it difficult to establish a productive vineyard. You may look at historical practices in the region and consult experienced growers to gather information and avoid mistakes. Ultimately, vine spacing decisions should be customized based on the specific characteristics of the site and the desired goals for vine development and fruit production.
Q: What is the significance of deep roots?
A: Deep roots are significant to vines as they provide access to water, nutrients, and minerals that are further below the soil surface. Drought resistance is one of the key benefits of deep roots, as they allow vines to access water from deeper within the soil, where it may not be available to shallower-rooted plants. Additionally, deeper roots can potentially provide a more stable nutrient supply, which may impact the growth of the vine and, consequently, the quality of wine produced. However, the relationship between deeper roots and wine quality requires further research. Nonetheless, deeper roots may be beneficial for longevity and higher crop yields by reducing the risk of vine decline from overcropping.
If you want to learn more about grape growing, check out https://www.vineyardundergroundpodcast.com/vu042.
