The sight of small, unfamiliar plants growing densely beneath a bird feeder is a common observation for many backyard enthusiasts. These patches of greenery result from uneaten seeds, scattered or dropped by feeding birds, that find favorable conditions to germinate in the soil below. This phenomenon transforms a bird feeding station into a small nursery. Understanding what these plants look like in their earliest stages helps in managing the area around the feeder.
The Components of Bird Seed That Sprout
The proliferation of sprouts is primarily due to the inclusion of whole, unprocessed seeds in commercial bird seed mixes. These mixes often contain “filler” seeds, such as white proso millet, golden millet, and milo, which birds reject and kick onto the ground. These discarded seeds retain high viability and are ready to germinate when exposed to moisture and soil. Black oil sunflower seeds are particularly prone to sprouting if not fully consumed because they are sold whole, encased in a thin hull. The intact seed contains all the necessary components for a successful sprout. However, cracked corn, another common mix ingredient, is much less likely to sprout since the kernel’s internal structure has been broken, destroying the embryo.
Visual Identification of Common Seedlings
The appearance of young sprouts depends entirely on the seed type, with the earliest growth identified by the cotyledons, or first leaves.
Dicot Seedlings
Sunflower seedlings, which are dicots, emerge with two broad, oval-shaped, waxy cotyledons. The stem is thin and pale green. The first true leaves appear later, distinctly heart-shaped or slightly lobed with a serrated edge, resembling the mature plant’s foliage. Safflower seedlings, also dicots, emerge with two smooth cotyledons, but their true leaves quickly form a low rosette that can appear thick and slightly spiny.
Monocot Seedlings
Grass-like seeds, such as millet and sorghum, are monocots and present a different appearance. These sprouts emerge as a single, narrow, blade-like leaf, known as the coleoptile leaf, which has a rounded tip. The plant looks much like a thick blade of grass, and subsequent true leaves emerge in an alternate pattern.
The Environmental Impact of Bird Seed Sprouts
While sprouted bird seed may seem harmless, these plants are often considered opportunistic weeds in a landscaped setting. Grains like millet and sorghum are typically not native and can compete aggressively with lawn grasses or garden plants for water and soil nutrients. This competition is particularly pronounced under the feeder, where seed density is highest. A specific concern involves the allelopathic effect of black oil sunflower seed hulls. As these shells decompose, they release chemical compounds that inhibit the growth of other nearby plants, including lawn grass. This often results in a bare, circular patch of soil beneath the feeder. Although rare, some low-quality birdseed mixes may contain trace amounts of actual weed seeds, raising the possibility of inadvertently introducing a non-local or invasive plant species.
Strategies for Sprout Prevention
The most effective method for preventing unwanted sprouts is to remove the viable seeds from the bird feeder equation entirely.
Switching to “no-waste” bird seed blends is a highly recommended solution. These mixes contain seeds that have already been hulled or shelled, such as sunflower hearts. Since the protective outer shell is removed, the seed’s embryo is non-viable and will not germinate if it falls to the ground.
Another practical approach involves using a seed catcher tray or a baffle placed directly beneath the feeder to intercept any dropped material before it reaches the soil. These trays contain the spilled seeds and hulls in a confined space, making it much easier to clean the area regularly and dispose of the debris.
For those determined to use whole seeds, a process of heat-treating the seed, such as baking it at a low temperature for a short period, can sterilize the seeds. This kills the embryo without significantly altering the nutritional value for the birds. Regular raking and cleaning of the ground under the feeder also helps to remove the seeds before moisture can trigger the germination process.