Strawberry cultivation traditionally relies on a layer of organic material placed around the plants, a practice known as mulching. Straw has long been the standard choice, forming the historical basis for the plant’s name. However, not all gardeners have access to clean, weed-free straw, or they may simply prefer a different material. This guide explores several practical, accessible materials that can be used instead of straw to support healthy fruit production.
Why Mulching Strawberries is Essential
A protective layer of material on the soil surface is a foundational practice for successful strawberry growing. Mulch creates a barrier that physically separates the developing fruit from the moist soil, preventing the berries from becoming dirty and reducing the risk of gray mold and other soil-borne diseases. Without this separation, rain splash can transfer pathogens directly onto the ripening fruit.
The layer also acts as a powerful weed suppressor by blocking sunlight from reaching weed seeds in the soil, preventing their germination. This reduction in competition ensures that water and nutrients are directed to the strawberry plants instead of to unwanted growth.
Furthermore, mulch is instrumental in moderating soil temperature, keeping the shallow roots cooler during the heat of summer while also insulating the crowns against damaging temperature fluctuations and frost heave in the winter. Finally, the covering minimizes surface water evaporation, which helps to maintain consistent soil moisture and reduces the overall need for irrigation.
Biodegradable Alternatives
Gardeners seeking a loose, natural material that breaks down over time have several excellent biodegradable options.
Shredded Leaves
Shredded leaves are a highly accessible material that can be spread around plants to a depth of several inches. This light, fluffy layer excels at moisture retention and gradually adds organic matter to the soil as it decomposes. However, it may mat down and reduce air circulation if applied too thickly after rain.
Pine Needles
Pine needles, often called pine straw, are another effective choice, particularly in areas where they are readily available. These needles interlock when applied, creating a loose, breathable layer that is slow to decompose, offering long-lasting weed suppression. Pine needles have a slightly acidic pH, which can benefit strawberries, a plant that thrives in slightly acidic soil conditions.
Wood Products
Composted wood shavings or aged wood chips can be used, provided they are well-aged or composted to prevent nitrogen depletion. Fresh wood materials can temporarily tie up nitrogen in the soil as they break down, potentially starving the strawberry plants. When using aged wood products, apply them in a thick layer to maintain their insulating properties and block light from weeds. Using organic materials like these also supports soil life, such as earthworms, which improve soil structure and fertility over time.
Sheet and Fabric Substitutes
Alternatives that function as solid barriers offer maximum weed control but require a different application method than loose materials.
Landscape Fabric
Landscape fabric, or woven ground cover, is a durable, long-term option that provides excellent weed suppression while allowing water and air to pass through to the soil below. This material must be cut with holes for each plant. Over time, organic debris accumulating on top can allow weeds to root into the fabric itself.
Black Plastic Sheeting
Black plastic sheeting, a non-porous option, is often used in commercial settings and is highly effective at blocking weeds. The dark color absorbs solar radiation, which warms the soil significantly in the spring, promoting earlier growth. However, this non-porous nature means rainwater runs off the surface, and it can cause roots to overheat in hot climates unless the edges are properly ventilated.
Newspaper and Cardboard
A more accessible barrier is a layer of newspaper or cardboard, which offers a cheap, temporary form of sheet mulching. Multiple layers of newspaper or a single layer of flattened cardboard boxes can effectively smother weeds. Because this material is light and visually unappealing, it should be covered with a thin layer of compost or another loose mulch to hold it in place and improve aesthetics as it slowly biodegrades into the soil.