Throughout our Regenerative Viticulture Series episodes to date, many leading viticulturists, agroecologists, and soil scientists have demonstrated that the space between (and underneath) your vine rows is central to vineyard health. 

A key tool to support the nourishment of these areas is plants themselves. As Dr Christine Jones, groundcover and soil ecologist, teaches: diversity aboveground is directly linked to the health and carbon storage capability of the soil, as well as pest and disease resistance of any plants communing with that soil, including vines.

So given this new set of guiding principles, we are rethinking cover crops; not just as groundcover, but as “eco-crops” (an investment in your soil ecosystem), in the words of soil scientist & regenerative agronomist Chuck Schembre. 

In this article, we have synthesised all of the specialist advice on cover crops for vineyards from the Regenerative Viticulture Series to date, including biological mechanisms and practical ground-level learnings shared by Dr Christine Jones, Chuck Schembre, Sérgio Nicolau, Mary Retallack, Nick Paulin, and Jordan Lonborg.

To delve into why cover crops are such a powerful tool, we first need to understand the relationship between plants, soil, and carbon. 

Dr. Christine Jones teaches that the majority of soil carbon is produced through the fungal energy channel (or liquid carbon pathway), a system through which plants send down atmospheric carbon to their roots in the form of liquid sugar. This goes as follows:

• Step 1 – Photosynthesis
  Living cover crops use sunlight and atmospheric carbon dioxide to photosynthesise, producing complex carbon compounds (sugars, carbohydrates, and organic acids).

• Step 2 – Exudation
  Plants channel up to 40% of these sugars down into their roots, releasing them into the surrounding soil as root exudates.
  

So far we have learned that the more plants you have aboveground, the more microbial biomass you will see belowground and the more carbon rich your soils will be. 

Next, we’re looking at functional diversity: a key component to ensuring that the soil benefits from your groundcover. Functional diversity isn’t just having lots of different species of plants, but rather, selecting a range of species from different plant functional groups, like brassicas, legumes or amaranths (See Dr Christine Jones’s full list of plant functional groups here). We’re aiming for functional plant diversity feeding into functional microbial diversity.

• More functional plant diversity, less plant competition
  Dr Christine Jones goes as far to say that having plants from different functional groups is vital, as plants from the same functional group can end up competing with each other. For instance, if you have only grasses as ground cover, these plants will begin competing with each other for resources like water and minerals. If however, you have 4+ functional families planted together, evidence suggests that these plants behave cooperatively, sharing their resources between them. In essence, functional plant diversity is vital for creating a collaborative, not competitive, environment in the soil.

• More microbial activity, more carbon rich soils
  Mary Retallack, agroecologist, scientist and viticulturist, cites a study that found that wallaby grasses and leguminous mixes with annual grasses grow well alongside grapevines, and were able to produce more than double the amount of soil microbial activity and sequester more carbon than systems using traditional herbicide practices.

• Microbe sharing & endophytes
  Dr Christine Jones shares that plants from different functional groups can work together and share their beneficial microbes. For instance, if a cover crop grows alongside a deep-rooted, drought-tolerant herb, the cover crop can signal to microbes around the neighbour plant’s roots for help when there are drought conditions. The cover crop can then ingest donated microbes as endophytes (internal plant microbes) that “switch on” genes for water retention during dry spells. When the vine doesn’t need these endophytes anymore, they’re expelled and the gene is “switched off”.

• The “soil sociobiome”
  Microbes communicate with each other and with plant roots via chemical signaling. Dr Christine Jones states that diverse root exudates activate dormant soil microbes through chemical signalling, expanding the soil sociobiome and stimulating microbial activity.

• Redox potential
  Sérgio Nicolau, 5th generation regenerative viticulturist and agronomist, notes that different plants alter the soil’s oxidation-reduction (redox) status. Species such as clovers (legume), black oats (grasses), and mustard (brassica) encourage a reductive soil environment, which is naturally disease-suppressive compared to oxidative monocultures (such as GMO plants).

• Improves soil structure & water infiltration
  In arid climates or regions vulnerable to heavy downpours, bare soil leads to runoff, and erosion. Sérgio Nicolau observed that different plant heights intercept falling raindrops, breaking their kinetic energy before impact on the soil. Below ground, diverse root lengths and systems break up hardpan layers, creating macropores that allow rain to infiltrate deep into the profile rather than washing topsoil away.

While annual cover crops are an excellent entry point, Australian agroecologist and third-generation viticulturist Mary Retallack advocates for moving toward 100% functional, year-round perennial ground cover and native plant integration.

Rather than disturbing the soil with annual sowing, Mary’s EcoVineyards program encourages establishing native perennial species in mid-rows and under-vine to provide:

• Shelter – Perennial habitat for beneficial insects year-round
• Nectar – Fuel and energy for adult beneficial predators
• Alternative prey – Food sources to sustain predator populations when vine pests are low
• Pollen – Essential nutrients that govern predator egg production and reproduction rates

In field trials, planting native perennial grasses and insectary shrubs in and around vine blocks increased predator populations by over 27%, including: lacewings, ladybirds, wolf spiders, and parasitic wasps that keep scale, mealybugs, and light brown apple moth populations under control.

Whether you’re trialling a new cover crop mix, adjusting your termination timing, or planting native insectary plants to improve biological pest control, understanding what’s working requires good observational records.

Sectormentor makes it straightforward to log vineyard observations, track soil health progress, and build a long-term picture of how your land is responding to regenerative practices. Over time, that data becomes one of your most valuable assets, helping you make better decisions according to your vineyard context.