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Native Cover Crops for Vineyards:

"Big 3"

Blue Wildrye (Elymus glaucus)
Meadow Barley (Hordeum brachyantherum)
California brome (Bromus carinatus)

"Little 3"

Molate Red Fescue (Festuca rubra)
Idaho Fescue (Festuca idhaoensis)
Pine Bluegrass (Poa scabrella)

There are substitutions and additional plants that can be added to the above mixes, but these are the basic mixes.

Permanent Cover Crops (Benefits and Potential Problems):

There are many potential benefits for using no-till perennial grasses. Some of the benefits are as follows:

1.) Erosion control: The "Big 3" have much greater seedling vigor than the "Little 3" and will provide better initial erosion control. The "little 3", slow to become established, will benefit from an additional seed type, such as Zorro fescue, added to the initial mix. Once the "Little 3" becomes established it will provide excellent erosion control

2.) Pest management: Both mixes provide a habitat for natural predators as well as cut down on dust problems in the vineyard. The "Big 3" seem to provide a better habitat for natural predators

3.) Increase field accessibility

4.) Lower energy use

5.) Improve water quality in watershed: The quality of both surface and ground water are improved

6.) Soil Improvements: Soils are improved by the increase in humates, C.E.C., microbial populations and diversity, water penetration and water holding capacity. Soil structure is also improved and soil compaction is decreased

7.) Vigor control: Excessive grapevine vigor can be successfully controlled with the proper selection of a cover crop. Potential problems include excessive water and nutrient competition with the grapevine causing excessive stress to the grapevine, soil microbial imbalances, rodent control and the cost of initial establishment.

Pre-Plant Considerations:

The goal of the pre-plant considerations is to gather pertinent information about the grapevine, soils and microclimate in order to maximize the potential benefits of the cover crop within the current growing regime and minimize potential negative affects of cover cropping. Important aspects to consider prior to the selection and planting of the cover crop are:

1.) Age and health of the vineyard

2.) Rootstock variety; vigor, water needs and rooting characteristics

3.) Layout and trellis design

4.) Erosion potential of soil

5.) Soil condition; mineral and microbial balances, organic content of soil, Carbon/Nitrogen ratio, water holding capacity of soil, soil structure and soil compaction

6.) Water availability and quality

7.) Existing and potential pest and disease problems

8.) Weed problems; existing or potential

9.) Climate

10.) Economics

Planting and Establishing the Cover Crop:

Permanent cover crops are expected to last for many years in the vineyard without needing to be re-seeded; therefore, careful consideration must be given to preparation of the soil for cover crop planting. Any soils work such as land leveling, ripping, rock picking, soil analysis and soil mineral amendments, etc. must be completed prior to planting the cover crop. To complete the preparation of the soil for planting, the best possible seedbed should be prepared. The ideal seedbed should have rows properly graded, be as free of large rocks, potholes and bumps as possible and the soil in the areas designated for the seedbed should be finely worked. The seed should be planted in the fall, using either a seed drill or a broadcast seeder, and if possible irrigated to speed germination. If it is not possible to irrigate try to cover the seedbed with straw. The best straw to use is from one of the seed types used. The straw will help to retain soil moisture after a rain and help protect the seedling from desiccation and from rain and wind erosion.

Managing the Cover Crop:

The "Big 3" and the "Little 3" should be handled differently in the first growing season.

"Big 3":
These grasses have high seedling vigor and should be easy to establish in the first growing season. In the spring of the first year enter the vineyard as late as possible to avoid creating ruts in the driving row. The "Big 3" can be mowed to a height of 8 to 12 inches in early winter and spring, but should be allowed to go to seed before a final mowing. Mowing two to three times per year will usually be adequate. If not supplied with irrigation water or rain the grasses should go dormant by June. Mowing to a final height of about 8 to 10 inches will leave enough thatch to help compete against summer weeds.

"Little 3":
These grasses have less seedling vigor and are slower to establish. The first year may yield a high degree of weed competition. Mowing competing weeds as they grow higher than the "Little 3" grasses will help favor the "Little 3". Do not mow the "Little 3", if possible, because they will not seed if mowedprior to seeding. By the second or third year the "Little 3" should be well established and be able to out- compete weed growth. Once established the "Little 3" may not need to be mowed because they tend to go dormant early and are lower growing than the "Big 3".

Monitor Grapevine Health:

Grasses can remove large amounts of nitrogen as well as other minerals from the food cycle that normally feeds the grapevine. It is very important to monitor the soil nutrient levels and the nutrient levels within the grapevine and feed the soil and grapevine as needed.


(written by Ed Kelly)

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