Covercrops is a term that covers the planting of other plants/crops between the vines in our vineyards. Planting covercrops is a commonly used technique in organic and biodynamic farming. 

We plant covercrops for several reasons. One is to work on the structure of the topsoil as the roots of the selected plants can both loosen up, aerate and provide better drainage in topsoil. Another, and for us even more important is to bind nutrients over winter when our vines are dormant. For example this winter we planted beans in every second row as they absorb and hence "bind" vital nutrients, especially nitrogen. In spring when our vines begin to awaken vi cut and shred the bean plants and mix them with the topsoil using a harrow and thus release the nitrogen (and other nice things) they've absorbed over winter so our vines can benefit from it and start the growing season strong. 

Other plants commonly used as covercrops are different grasses and legumes but especially rape, mustard, radish and buckwheat. 

A third reason for planting covercrops is to use them to attract or (more rarely), repel, certain insects or animals. To give you an example specific plants attract ladybugs that love to feed on aphids and thus helps keep you wines healthy in a most natural way. 

Finally, covercrops can also help combat erosion and help support biodiversity in your vineyards. 

So all in all covercrops are an amazing way of working WITH nature to help making our precious vines stronger, happier and healthier, all naturally! 

A small bonus info; you will often find roses planted at the end of the rows of vines in some wineregions. Many winegrowers used to do this as roses are highly susceptible to both aphids and other harmful bugs, also fungal diseases and as such, function as a kind of alarm, or warning system before the plagues attack the vines and does irreversible harm.