WINTER MULCH FOR STRAWBERRIES
By Sonia Schloemann, UMass Extension

An important fall job in commercial strawberry production is mulching. Strawberries are commonly grown in cold climates, such as the northern US and Canada, but the strawberry plant itself is actually quite vulnerable to cold injury. Research has shown that, without mulch, strawberry crowns can suffer damage at temperatures below 12°F and unprotected strawberry plants can suffer desiccation damage from drying winter winds. A protective mulch can protect strawberries from cold by providing insulation, and from desiccation by providing a barrier against drying winds. Mulches will also protect plants from injury caused by soil heaving, which results from freezing/ thawing cycles during the winter. So, a key to consistent quality strawberry production in cold climates is in protecting the plants from severe temperatures or temperature swings through the practice of mulching.

Production systems can also affect the need for mulching. Plants on raised beds, for example, are more vulnerable to cold and desiccation injury than plants in level plantings, especially in locations that are exposed to strong winter winds. Annual production systems, such as fall planted plasticulture, may utilize less hardy or disease susceptible cultivars. As we will see, mulching practices must adapt to these new systems.

When should the strawberry grower plan to apply mulch? Research suggests that a good timing guide is to apply mulch after three consecutive days with a soil temperature of 40°F or below. This soil temperature usually occurs after multiple frosts, and when the plants have slowed growth in response to cooler temperatures. It is best to apply mulch before the soil freezes solid. In New England mulches are applied in late November.

What is a good mulch material? The traditional mulching material for strawberries in New England is straw. Straws from wheat, rice, oats, or Sudan grass work well. Straws coarser than Sudan grass are not recommended. Straw should be clean, free from weed seed, and contains a minimum of grain seed. Strawberry growers can produce their own straw, often cutting the straw before the grain seed is viable. Store straw for mulching in a dry area. Occasionally, grain seedlings can become a weed problem the following spring; an application of sethoxydim will give good control.

How much mulch should be applied? A traditional, level matted row planting will require 2.5 to 3 tons of straw per acre for a 2 to 3 inch deep mulch, or about 300 small bales of average weight. Raised bed plantings and sites with strong wind may require twice this amount for adequate coverage. How is the mulch applied? Smaller plantings may be mulched by hand by shaking out the bales of straw over the row. Larger plantings often use bale choppers to break up the straw bales and distribute the straw over the bed. Choppers are available for both small bales and large round bales. How and when is the much removed? In the spring, when plants begin to show growth under the winter mulch (new green tissue), the mulch should be raked off the rows to allow sunlight to penetrate and reach the foliage. Delaying removal will delay plant growth and flowering and may reduce yield. Mulch can be raked off by hand with ordinary yard rakes in smaller plantings. In larger plantings, various mechanical tools are available ranging from
modified hay rakes and tedders to equipment specifically designed for the purpose.

Floating row covers as mulch. These covers are composed of a plastic such as polypropylene, spun-bonded into a fabric that is permeable to light, air, and water. Research and growers' experiences demonstrate that these covers are useful for winter protection of strawberry plantings. While floating row covers are available in several weights, only the heavier weights are recommended for winter protection. At present a widely available weight recommended for winter strawberry protection is 1.25 oz/yd2 (42 g/m2). A variety of fabric widths are available, with common widths ranging from 15 feet to 60 feet. This material currently costs about 4 cents per square foot. With proper care, this heavier fabric should last 3-4seasons. Floating row covers are widely used to protect annual plasticulture plantings.

Row covers are best applied on still days. Be sure to line up sufficient labor to place the row cover. If possible, use wider widths for more efficient application. The row cover edges must be anchored, as must areas where two covers overlap. A variety of methods are used to anchor the edges. Edges may be anchored with posts, rocks, or tube sand. The edges may also be covered with soil. Once the mulch is in place, the job is not done for the winter. Monitor the planting frequently. If straw has blown off areas, replace at once. Watch the edges of row covers, and adjust anchors if needed. Repair any rips or holes as soon as possible.

GET MONEY TO TEST A NEW IDEA

The Northeast Sustainable Agriculture Research and Education (SARE) Farmer Grant program provides up to $10,000 to farmers to develop, refine, and demonstrate new sustainable production or marketing techniques. To be eligible you must farm in the Northeast.  You don’t have to be a farm full-time but you must have an established crop or livestock product that you sell on a regular basis. Non-profit farms may apply if the primary activity of the farm is to produce and sell food under the kinds of economic constraints that affect commercial growers. The application is very straightforward, and it’s available online at www.uvm.edu/~nesare. There’s also a helpful guide called “How to write a SARE farmer grant application”. You can download these or have them mailed to you by calling 802-656-0471. You are required to have a technical advisor from Extension who can look over your proposal and sign it before it is submitted and then be available to help you with your project should it be funded. Applications must be postmarked by December 22, 2006.

A LEGAL GUIDE TO FARMING IN VERMONT

This new publication covers a wide variety of the legal aspects of farming, including the legal structure of the farm business; farm transfer and estate planning; farmland tenure and leasing; and regulation of farm labor, organic agriculture, agriculture and land use, and on-farm food processing and marketing. The guide is primarily intended for use by Vermont farm service providers -- Extension, land trust, and farm agency personnel; attorneys; and others who work directly with farmers on farm start-up, farm viability, or farm transfer issues. Farmers will also find the guide useful. While not a substitute for legal advice, the guide may be a useful resource when developing a list of questions for an attorney, accountant, or farm service provider. In addition, farmers may use it to identify and address issues that need to be included in the farm’s business plan or to become better informed consumers of legal or farm viability services. The guide is available on-line at www.uvm.edu/landlinkvt. For more information, contact Deb Heleba at debra.heleba@uvm.edu or (802) 656-0233.

VEGETABLE PRODUCTION WORKSHOP: FROM GREENHOUSE TO MARKET

This in-depth workshop takes place Dec 11-13 in Saratoga Springs, NY, not far from southwest Vermont. It features detailed presentations and group discussions with four experienced and successful vegetable farmers: Dan Kaplan, MA; Paul Bucciaglia, CT; Jim Crawford, PA, and Jack Hedin, MN. The workshop will focus on all aspects of greenhouse production, crop varieties, field production (including soil management, tillage, cultivation, and rotations), insect, weed, and disease management, recordkeeping for profitability, harvesting techniques, post-harvest handling/storage, and marketing. This workshop is designed for all levels of farmers with any size farm and any type system (conventional, organic, etc.). Participants must pre-register. Cost is $175 which includes daily meals and a binder of information. Contact Sandy Arnold at 518-638-6501 or arnold3@capital.net

HOLD THE DATE

The Annual meeting of the Vermont Vegetable and Berry Growers Association will take place on February 26, 2007 at the Capital Plaza Hotel in Montpelier. Stay tuned for details on the program.