Once the harvest is complete it is tempting to forget about the vineyard and focus on making wine, however, this time is exceptionally important for the vines and future vintages. The period in focus is after the ripe fruits have been harvested and before the leaves start to fall from the vines.
During this time the vines are hard at work storing carbohydrates in preparation for winter when they move into a dormant phase. It is during this busy time when the leaves are still healthy and green that they are photosynthesising and looking for as many nutrients as possible to prepare for the cold. Part of the lifecycle of the vine during the winter months is to enter a dormant phase where what we see above ground is bare of leaves. This is to ensure survival in the cold times, in some parts of the world vines survive under a blanket of winter snow. The stored carbohydrates are also the fuel for when the vines emerge from winter and enable budburst, it is vital there are enough energy reserves to ensure the next growing season.
You can imagine that the soil has done a lot of work at this point in the year to provide the valuable nutrients that ensure the vines grew quality and healthy berries to be made into your favourite wines. It is essential after harvest to evaluate the quality of the soil and add back the core elements that may be depleted during the growing season. The main elements are nitrogen, potassium and phosphorous with others like calcium and zinc to name a few.
There are two main practices to add nutrients to the soil, namely fertilising and planting cover crops. These can be used individually or together based on the estate’s approach to farming. Fertilising is just as one would do in their own garden at home where nutrient-rich matter is added to the soil. Choosing to fertilise allows you to accurately customise the mix of core elements needed for each vineyard base to the soil analysis results. Cover crops are plants grown between the rows of vines and introduce nutrients naturally and help oxygenate the soil. There is a range of cover crops to choose from, each with nuanced benefits. Some consistent benefits are protecting against soil erosion and reducing the need for herbicides when trying to keep weeds and invader species at bay. In addition to these, cover crops can help in rainy regions to use more water and stop the vine’s roots from staying too wet.
The availability of water during this period is also important to consider since it is needed to carry the nutrients deeper into the ground and provide the right hydration for the roots to absorb them. In dryer regions, farmers may decide to irrigate while dryland farmers are committed to relying on naturally available water.
Climate plays a role during this important time, in cooler regions the window is shorter which necessitates speedy soil analysis and action after the harvest, while in warmer regions, the vines retain their healthy leaves for a bit longer.