Succulents and Cacti make great additions to a naturalistic desert vivaria. Unlike many of the commonly used tropical vivarium plants, succulents and cacti pose their own unique set of needs that need to be addressed.
1. Succulents and Cacti require a well draining substrate that does not hold water. Most over the counter potting mixes and available naturalistic vivarium substrates are not suitable for growing succulents. Instead, create your own mix of 2 parts play sand to one part finely ground coconut fiber. Not only is this mix cheap, but it looks natural, as well. Extra organics, such as leaf litter, can be added if desired. This substrate should be placed on top of a drainage layer if being utilized in an enclosed container. A light misting every 1-2 days will provide any animal inhabitants with the water they need (adjust based on the specific needs of the species you are keeping), and only directly water the plants every 1-2 weeks.
2. Bright, high quality lighting is required by Succulents and Cacti. The desert is a bright place, and you'll want to mimic that in a desert vivarium. Generally, 2-3 times the light necessary to keep a tropical vivarium lush and vibrant is necessary to keep your cacti looking their best. Consider LED or T5 lighting systems. Make sure that there is never glass between the light source and your plants - with the high heat output from some lighting systems, plants can easily get burned! Keep in mind that most desert dwelling animals that are active during the day have very high UVA and UVB needs - a high quality UV source, such as Exo Terra's Solar Ray Metal Halide Bulb can provide both heat and light.
3. Great ventilation and overall low ambient humidity must be maintained. With succulents and cacti, not only can the substrate not stay wet or moist, but the air must be fresh and relatively dry. Humidity levels over 50% can create long term issues with cacti and succulents, including (but not limited to) rot and bacterial infections. A full screen top should be used with any naturalistic desert vivarium, and a fan to circulate air certainly is not a bad idea.
For a wide variety of Succulents and Cacti, check out our Succulents and Cacti section on www.joshsfrogs.com!