You can’t hear it, but all over our vineyards, engines are starting up. They run more quietly than electric engines, and they’re greener. Literally.
The leaves that are growing at the moment are the engine of the vine. They convert the sun’s energy into carbohydrates that power the plant.
Currently, they’re producing florets – the beginning of flowers that will later develop into bunches of grapes. When the grapes start forming, the leaves will power them to grow and sweeten.
“Our focus is to grow grapes, not an overabundance of leaves,” says Tony Smith, our viticultural manager in Hawke’s Bay. “We have to keep the engine running, so we can grow the grapes we want, but not running so fast that we get too much leaf.”
Water acts like fuel to an engine, and by moderating the amount of water the vine gets, our viticulturists can slow down or speed up leaf growth, helping to keep the vine in balance.
The leaf runs on water that it gets from the roots and releases through tiny pores called stomata. In the exchange of gases on the leaf surface, the leaf combines carbon dioxide with water to create carbohydrates. This, in turn, gets converted into growth – of shoots and leaves, but importantly also of florets and, later in the season, grape berries.
And all this production happens so quietly that you can hear the wind rustle through the leaves. Pretty magical!