Vermiculite is a mineral that is used as a soil amendment in gardening and horticulture. It is lightweight, absorbent, and sterile, and does not deteriorate over time. Vermiculite can absorb three or four times its weight in water and also attracts various plant nutrients such as potassium, magnesium, and calcium, making it useful for propagation and for potting up plants that do best in moist compost, including house plants. Vermiculite is also used as an anti-caking agent in fertilizers. Here are some of the main uses of vermiculite:

• Seed sowing and propagation: Vermiculite helps to aerate soil while simultaneously retaining water and nutrients, which it then releases over time. Vermiculite is therefore useful in seed sowing and propagation. It can also be added to house plant compost.

• Potting soil: Vermiculite is an excellent addition to pots of soil, whether that be in outdoor containers or for houseplants. Mixing some vermiculite into your potting soil will improve aeration and moisture retention, resulting in a healthier root system that is better able to spread out and absorb nutrients, thereby creating a lusher plant. Vermiculite is better for water and nutrient retention than perlite and is best used for plants that need more moisture to grow.

• Bulb and root crop storage: Vermiculite is an ideal medium to use for storing bulbs or root crops over winter, as it absorbs any moisture that might cause decay.

• Lawn seeding: A 1/4-inch layer of vermiculite helps keep grass seed from drying out while it germinates.

• Worm bins: Vermiculite is even a good addition to worm bins, providing grit that helps worms digest food.

• Flower arranging: Vermiculite can be used when arranging flowers. Fill the container with vermiculite, thoroughly saturate with water, pour off the excess, and arrange the flowers. This eliminates the need to change the water, eliminates spills, and helps keep the flowers fresh.

Vermiculite is sold in bags at the garden center or online. It is important to note that vermiculite was once commonly contaminated with asbestos, so it is important to purchase vermiculite from a reputable source.