Which method is unlikely to be effective in controlling rodent populations in gardens?

Using fumigation methods is unlikely to be effective in controlling rodent populations in gardens primarily because fumigation is typically reserved for enclosed spaces and requires specific environmental conditions to be successful. Fumigation involves the use of gaseous pesticides that can penetrate structures to eliminate pests, but gardens are open environments where the gases can disperse quickly and may not concentrate sufficiently to have a significant impact on rodent populations.

In contrast, using natural predators, planting deterrent plants, and building physical barriers are all more applicable strategies for gardens. Natural predators can help keep rodent populations in check through a balance in the ecosystem. Planting deterrent plants can create unfavorable conditions for rodents, discouraging them from entering the area. Building physical barriers, such as fencing or barriers made from hardware cloth, can effectively prevent rodents from accessing the garden. Each of these methods is more suitable for the unique conditions of a garden setting, making them more effective for rodent control compared to fumigation techniques.