Perlite is great for seed starting mixes and blending your own custom potting soil mix Helps lighten and loosen heavy, compacted soils White granular pieces that contain about 6 percent water Perlite has a neutral pH level Holds nutrients and three to four times its weight in water Clean, sterile, odourless, and non-toxic Works as a lightweight sand substitute Won’t rot or mould Tends to float to the top of potted plant containers due to its light weight. FOR AN EXPLANATION - VERMICULITE OR PERLITE SEE THE "DESCRIPTION" BELOW.
WHAT IS PERLITE
Perlite is made from volcanic rock, which is heated and crushed until it explodes in order to transform the rock into small white pieces. It has medium water retention ratings and low nutrient retention ratings. It is added to soil mixes in order to improve the drainage capability of both soil-based and soil less potting mixes.
Perlite helps insulate plant’s roots from extreme temperature fluctuations. It’s also used as a protective coating on pelleted seeds. Perlite is lightweight, odourless, clean, and easy to handle. It has a pH of 6.6 to 7.5. Add perlite to your soil for plants which need their soil to dry out between watering, such as cacti or succulents.
WHAT IS VERMICULITE?
Vermiculite is magnesium-aluminum-iron silicate. It is an all-natural mineral product that is mined out of the ground and then processed into a soil additive that mainly increases water retention and nutrient retention levels in soil. It looks similar to mica with its layers or stacks, which are suited for trapping water. It has high water retention and high nutrient retention levels. Vermiculite’s water-holding capability makes it perfect as an anti-caking agent in dry pesticides and fertilizers.
Contrary to rumour, vermiculite does not contain asbestos and it is not a type of asbestos. The medium is considered safe for commercial and personal use.
Vermiculite and perlite do share many qualities. Both products are inorganic, lightweight, and relatively sterile. And of course, both are used as a soil amendment to aerate soil—though perlite provides more aeration than vermiculite. Both perlite and vermiculite are highly porous, making them able to hold water in the soil so it’s available for your plants. However, vermiculite holds more moisture and keeps it available in the soil longer than perlite will.
So how do you know which one you should choose? If the plants you’re growing need the soil to stay on the wetter side, opt for vermiculite. Vermiculite is also the best choice if the plants in your garden are sensitive to alkalinity in the soil. Vermiculite is also the go-to when it comes to starting seeds because it protects seedlings against damping-off and other fungal diseases that can threaten them as they start to grow.
Although perlite doesn’t hold onto water as long as vermiculite, it boosts the humidity as it releases the water. Many plants thrive in high humidity, so if that’s a concern in your garden, perlite is right for you. Perlite is optimal when it comes to rooting cuttings from established plants because it helps prevent the rot that can otherwise be a challenge. Perlite is also the best option for planting epiphytes, cacti, succulents, and other plants that require plenty of drainage and aeration (and can tolerate a slightly higher pH level).
In short, choose perlite for cacti, succulents, epiphytes, when you’re rooting cuttings, and whenever quick drainage or maintaining high humidity is a concern. Opt for vermiculite to start seeds or whenever you’re working with plants that need their soil to retain moisture.