Spray a castor-oil solution around and in mole holes.
Moles often make their way into backyards and gardens in early spring. They awake after being dormant for the winter and search for worms. You may notice that your garden has been invaded by these rodents when small holes appear in your soil. Moles won't typically disturb your vegetation directly, but when worms are removed from the soil the growth potential of your plants and vegetables decreases.
The least harmful way of deterring moles from getting into your garden is by laying down medium-gauge wire screen. The openings in the screen should be large enough for the stems of your plants to grow through, but small enough to discourage moles from digging. The best time to lay the screening is before planting your garden.
Use one long sheet of screening to cover the surface. Secure all four corners as well as the midpoints between the corners; this will prevent moles from climbing under the screen to reach your soil. Once you have laid down your screen, plant your garden as usual by pushing the seeds into the soil through the middle of the openings in the screen.
To further protect your garden, add a layer of cut grass and wood chips over the top of the wire screen in areas in which you have not planted.
Most store-bought mole repellents contain castor oil, and a similar solution is easy to make at home. Many gardeners find that mixing 1 part dish soap with 2 parts castor oil in 1 gal. of water is the most effective solution for repelling moles.
When you have combined the ingredients, pour the mixture into a large spray bottle. Spray the solution around the mole's holes and inside them as well. When you begin preparing your garden, use the same solution to spray the perimeter before any of the plants sprout. This will send moles to other locations in search of food.