To keep cats away humanely and effectively, you can use a combination of scent deterrents, physical barriers, and motion-activated devices. Here are the main methods:

Scent Deterrents

Cats dislike certain smells, so using these can help keep them away from your yard or garden:

• Citrus peels (orange, lemon)
• Garlic, mustard, pipe tobacco
• Vinegar (sprayed diluted or full-strength around garden edges)
• Coffee grounds or cayenne pepper
• Essential oils like citronella, eucalyptus, peppermint, lavender, lemon grass, and rue (a herb cats avoid)
• Planting cat-repellent plants such as rue, rosemary, lavender, marigolds, pennyroyal, Coleus canina (scaredy-cat plant), and lemon thyme

Physical Barriers and Garden Modifications

• Place plastic mats with flexible spikes or chicken wire just under the soil to prevent digging
• Use sharp-edged mulch, pine cones, lava rocks, or large river stones as ground cover
• Scatter pine cones or place plastic forks or chopsticks with the tines up in garden soil
• Use stone chippings, pebbles, or netting to make the garden less inviting
• Block access to sheltered spots cats like, ensuring no cats are trapped inside before sealing off areas

Motion-Activated Devices

• Motion-activated sprinklers that spray a short burst of water when cats enter the area are very effective; cats quickly learn to avoid the space
• Motion-activated ultrasonic alarms emit sounds unpleasant to cats but inaudible to humans

Additional Tips

• Secure outdoor trash cans to prevent cats from scavenging
• Talk to neighbors if they feed stray cats, encouraging spay/neuter programs to reduce populations
• Provide a designated cat-friendly area with catnip and sand to lure cats away from your garden

Combining these methods and reapplying scent deterrents regularly (especially after rain) will improve success in keeping cats away without harm