Commercial bird seed mixes contain many components that are biologically capable of germination and growth. These mixes are essentially a collection of various grains and oilseeds, many of which are intended for agricultural cultivation. The degree of sprouting depends entirely on the specific seeds included in the mix and how they have been processed. Most components will readily sprout if they land on moist soil.
Identifying Viable Seeds in the Mix
The capacity for growth within a bird seed mix is directly related to the viability of the whole seeds it contains. The most common components that will sprout are the various forms of sunflower, millet, and safflower.
Seeds That Will Sprout
Whole sunflower seeds, particularly the thin-shelled black oil variety, possess high germination rates and will quickly grow into tall plants. Safflower seeds are also frequently viable, producing an annual thistle-like plant that can reach heights of up to five feet. Different types of millet, such as white proso, red, and golden millet, are often used as filler in less expensive blends. These annual grasses are notorious for sprouting in lawns and garden beds. Whole corn kernels, which are sometimes included in ground-feeding mixes, will also germinate and develop into full-sized corn stalks.
Seeds Unlikely to Sprout
Conversely, certain components are unlikely to grow, such as cracked corn, hulled sunflower hearts, and Nyjer seed. Nyjer seed is heat-treated during importation to prevent germination.
Unintended Ecological Outcomes
Allowing bird seed to sprout can lead to negative consequences for the local environment and garden health. Many of the grains used in bird feed, such as certain millets, wheat, and flax, are classified as agricultural weeds when found outside of cultivated fields. When birds discard these less-preferred “filler” seeds, they introduce potential weeds that compete with intentionally planted vegetation for light, water, and soil nutrients.
The dense, unintended growth from spilled seed can also create an environment that attracts unwanted pests. Accumulations of discarded seed and husks can harbor mold and bacteria, posing a hygiene risk, and the resulting thick plant growth can offer cover for rodents.
Furthermore, studies have shown that some commercial bird seed blends contain seeds from species that are considered invasive in certain regions. This means the act of feeding birds inadvertently contributes to the spread of non-native plant life. These species can aggressively displace native plants, altering the structure of the local ecosystem.
Managing Sprouting Under Feeders
To prevent the unwanted growth that occurs beneath feeding stations, several practical adjustments can be made to both the seed and the setup.
One effective method is to switch to “no-mess” seed blends, which consist of hulled or shelled sunflower, peanuts, and other seeds that have had their outer shells removed. Since the hull is necessary for germination, these seeds cannot sprout even if they fall to the ground.
For feeders using traditional, unhulled seed, installing a seed-catcher tray directly beneath the feeding ports will physically block most fallen material from reaching the soil.
Regularly raking and removing any accumulated debris or spilled seed from the ground every few weeks can also disrupt the germination process.
Placing pavers or a dense ground cover like clover beneath the feeder can help shade the soil, making it less hospitable for seed germination. Periodic rotation of the feeder’s location prevents a single area from being overwhelmed by a buildup of ungerminated seeds.