Field Day Recap
From Kelowna to Osoyoos, growers and researchers in the BC Living Lab are testing a big question:How to grow cover crops that help mitigate climate change and support vineyard production?Over two summer field days, Dr. Mehdi Sharifi and his team at AAFC Summerland shared what’sworking, what isn’t, and what to consider for inter-row cover cropping in wine grapes.
Know Where You Stand, Know Where You Want to Go
A group of growers, industry folks, andresearchers discussed how cover cropping inalleyways promises a lot of useful benefits – likesuppressing weeds, regulating temperature,providing nitrogen, and reducing soil compactionand erosion. But in practice, it’s difficult to knowwhich mix, seeding approach, or mowing regimewill yield results, especially given seed costs andrisks from variable weather.
Dr. Sharifi offered key considerations to help planfor the best chances of crop establishment:
- Success of a cover crop variety is highlysite-specific. Consider the soil, climate,irrigation, and management of your site morethan the promises of a specific variety. Forexample, crimson clover had great reviews,but when trialed needed more watering thanthe vines.
- Choose your goal(s) for the cover crop. Grasses are more resilient to drought, whilelegumes provide nitrogen that may offsetfertilizer inputs. Some varieties produce morebiomass, which could generate soil organicmatter or help suppress weeds.
In-Field Insights
Varieties differed across the Okanagan valley vineyards on tour, but growers were trialing acommon starting point – a mix that includes a grass, a legume, and (often) a ‘nurse crop’. A fast-growing nurse crop like tillage radish or oats helps the perennials establish by shielding seedlings,helping them grow upright, and suppressing weeds before its mowed midsummer. The result is acontinuously covered alleyway with longer-lasting soil organic matter, that can enhance resilience.
Getting Through Growing Pains
- Establishing cover crops in untilled groundis tough — pre-existing weeds and grassesoften form thick sod or outcompete seedlings,so surface cultivation is often needed.
- Equipment can require customization — insome cases the best tool, a no-till seeder,sunk into cultivated soil and planted seeds toodeep for consistent germination.
- Balancing irrigation takes trial and error— cover crops generally need more frequentwater than vines (can be up to twice weekly).Success can depend on if the irrigation systemsupplies the alleyway with enough water.
What’s Up Next?
The BC Living Lab’s collaborative approach emphasizes the value of trialing, observing, and adaptingpractices to fit each farm’s goals and conditions. While working with growers to trial feasibility onactive farms, researchers are continuing to assess how cover crops contribute to storing carbon inthe soil and reducing greenhouse gas emissions. Investigating drought-tolerant species, interactionsbetween temperature and moisture, and developing a cover crop selection tool are ongoing priorities.