Vermiculite size 4 - 8 mm = 1 pkt = 5Liter What is Vermiculite? Vermiculite interacts with potassium, calcium and magnesium in your soil. It also helps to raise the pH slightly of your plants even though it’s a neutral pH of 7.0. Vermiculite is made from compressed dry flakes of a silicate material which is absorptive and spongy. The color of vermiculite is a golden brown to a dark brown and is a sometimes difficult to tell from the potting soil it’s mixed with. When water is added to vermiculite, the flakes expand into a worm-like shape and act like an absorbing sponge. If you want to poke these “vermiculite worms” with your fingers, you’re not alone — that’s what I wanted to do when I first saw them too! Vermiculite is best used for plants that require soil to stay damp and not dry out. For plants that love water, using vermiculite or mixing a healthy scoop of it into your potting soil is the way to go. It can absorb 3 to 4 times its volume when water is added, making your pots a little bit on the heavy side. Since vermiculite acts like a sponge and absorbs more water than perlite, it doesn’t aerate the soil as well. This means less oxygen for plant roots. If you use it when growing plants that don’t need damp soil, you might find your plants suffering from root rot. So be aware of your plants’ needs when you decide how water retentive you want your soil to be. Which To Use In Your Garden? Use Vermiculite If… 1. You need an additive for plants that need to be kept moist 2. You want your seed trays to develop strong seedlings Vermiculite is odorless, can be purchased in horticultural-grade bags with directions on working it into the garden soil. It’s a permanent soil conditioner and won’t break down in your soil like compost does. When it is watered or it rains, the vermiculite will hold water in the soil until the soil begins to dry out and releases it. Vermiculite can be used in potted containers, on lawns and for composting. It can be used in mycology for mushrooms added to the substrate. It can improve the soil that needs an additive to retain water for your plants which need it.