With the change of seasons comes the beautiful transformation of our vineyards from vibrant and lively greens to deep oranges, golden hues and bright reds as summer gives way to a much-needed resting period – resting for the plants, that is, not for the people who work with them.
Seasonal Vineyard Maintenance
Once harvesting is completed, vines gather up soil nutrients for the winter period and the wood becomes visibly harder to resist the harsh winter colds. Although the growth period comes to a halt, the work of farmers and viticulturists in the vineyards continues.
Even though vineyards are entering dormancy, fertilisation is required in irrigation areas. Disease control is also important as wet and humid conditions remain a threat to vineyard health.
On Elgin Vintners, Marinda Kruger-Claassen and her team have used the down-time to eradicate an old Viognier block due to a drop in demand for the varietal wine and the block being well-matured. The soil will be prepared and allowed to rest for 12 months before being replanted in August 2021 with Pinot Noir.
Winter is also a time to plant cover crops between the vineyard rows, for soil health and management of pests, weeds and diseases. On Vondeling in Voor-Paardeberg, viticulturist Magnus Joubert and his team are planting a mixture of korog, barley and lupins. Korog, also known as triticale, is a cross between wheat and rye. Wheat provides good fibre while rye contributes to its long growth cycle. During winter and most of spring the korog matures and develops strong fibres before it gets flattened by a roller at the onset of summer to form good cover crops.
Korog and barley help to suppress weed growth and to form an organic mulch which increases carbon build-up in the soil, the main component of the organic matter that helps give soil its water-retention capacity, structure and fertility. Lupins, on the other hand, are great for nitrogen development which reduces the need for chemical fertilisers to provide the nitrogen that grape vines, like almost every other plant, need especially in the spring to jump start rapid growth.
Cover crops provide a host of benefits, including reducing fertiliser costs, reducing the need for herbicides and pesticides, improving vineyard yields by enhancing soil health, preventing soil erosion, conserving soil moisture, and protecting the water quality.
Winter Cover Crops Planted Between Rows
Once the first winter rains have fallen, vines are heavily pruned and all the shoots, except the dominant bearers, will be pruned back to allow for a well-deserved rest.
A lot of farms will only start pruning by mid-June when there has been at least 80% leaf fall. Vineyard rows will also be ripped to loosen soil compaction and assist with root pruning to stimulate new root growth in spring.
Kudzai Merengwa is busy with the same vineyard practices at De Grendel and says winter is the perfect time to maintain vineyards and fix irrigation and trellising systems where necessary.
Now we look forward to spring, the vines emerging from dormancy and the first bud break signalling the life cycle starting up again.