Designed to retain moisture and nutrients, this Westland Gro-Sure Vermiculite is a naturally occurring mineral that has been heated to produce lightweight, absorbent flakes. These flakes will also insulate plants and crops against temperature and humidity changes. Suitable for: Sowing seeds and potting Contents: Flaked Vermiculite Application: Lightly cover seed trays after sowing, or mix with compost Application Time: All year round Coverage: Light covering over seed trays, or at a rate of 30% as a compost additive Pack Weight: 10L