When selecting the lighting, make sure that the lamps have the required IP rating for the intended application. The IP code consists of two digits. The first digit indicates the level of protection that the enclosure provides against access to hazardous parts, while the second one shows the level of protection that the enclosure provides against harmful ingress of water. The IP rating lets you see how well a lamp is protected against the ingress of solid foreign bodies and liquids.
In addition to solar lights, you can also use LED lighting, energy-saving lamps, or timers to reduce power consumption. However, power in the garden can also be dangerous. Therefore, you should rather have a specialist install the garden lighting.