Is Colorado too cold for vineyards?

Colorado is for the adventurous. You have your choice between skiing, climbing, biking, and hiking. The conditions that make CO such a great place for the outdoors, like the long snowy winters and hot dry summers, make the area an interesting place for vineyards. The contrast between hot days and cool nights allows the grapes to concentrate flavors and tannin structure while maintaining their acidity and freshness. 

But, the uniqueness of Colorado weather also brings its challenges. Frost damage is one of Colorado vineyard’s greatest threats. During the spring, once the vines have broken their dormancy, their new green tissue and buds are susceptible to frost damage when the temperature drops below 30ºF, which is common in spring. This can damage the fruit and overall yield for that year’s growing season, it can also cause uneven ripening and poor fruit quality. In the fall, when the grapes are on the vine, an early winter frost can damage the existing crop, or force winemakers to pick the grapes before they have fully ripened. 

Another more serious frost issue is when temperatures drop to extremely low temperatures in winter below. Most grape varieties have a ‘cold hardiness’ of above -8ºF, with a few cooler climate vines like Riesling tolerating up to -15ºF. When the temperature drops below this point, the vine can be permanently damaged, killing the tissue that transports water and nutrients. When this tissue dies, vineyard owners must either retrain the vines from the ground up if the vines are on their own root stock.  Replanting is the worst case scenario and happens more often if the vines are planted on american root stock. 

Luckily, there are a lot of solutions to prevent frost damage. Colorado State University viticulturist Horst Caspari is an advocate of planting cold tolerant hybrid vines. These varieties can withstand temperatures below -15ºF. Cool climate areas like New York and Michigan have successfully planted these hybrids and are making interesting wines. This could be a creative solution for the CO wine scene. There are also many vineyard management techniques that mitigate damage, such as pruning styles that delay bud break to avoid spring frost damage or implementing fans in the vineyard, that help circulate warm air into the vineyard on nights with frost threats. 

We are resilient, adaptive, and creative here in Colorado, so the future is bright! And the cold doesn’t bother us.