What soil amendment should be recommended for improving a potting mix for cacti?

Recommending perlite as a soil amendment for potting mixes intended for cacti is advantageous because perlite improves soil aeration and drainage. Cacti thrive in environments where their roots can breathe, avoiding conditions that lead to excess moisture, which can cause root rot. By incorporating perlite, the potting mix becomes looser, promoting effective water drainage while still allowing enough air circulation around the roots.

Cacti are adapted to arid environments and require a potting medium that mimics such conditions. They do not require high moisture retention, making perlite a suitable choice compared to options that promote moisture retention, like peat moss, which is not ideal for cacti. While nutrients from compost or fertilizer are beneficial to many plants, cacti can often thrive in lower nutrient conditions, making the addition of these amendments less critical. Additionally, while shredded fir bark may provide some degree of drought resistance, its particle size and water retention properties might not provide the same level of aeration and drainage that perlite offers.