How to Garden With Vermiculite

Soil that is too sandy or that has a high clay content can't give your plants everything they need. Moisture passes right through sandy soil and has little nutrient content to offer, while clay soil is rich with nutrients but plant roots are likely to rot in its dense, water-retentive particles. Vermiculite is an inorganic soil amendment related to the mineral mica that can hold both water and nutrients in sand while keeping clay from compacting to improve drainage. Put vermiculite to work in the garden and in containers to improve soil texture and plant performance.


Put on a dust mask and gloves. Some bags of vermiculite can contain small amounts of the carcinogen asbestos.


Open the bag and pour in a small amount of water to dampen the product and decrease the potential of contact with airborne vermiculite dust.


Mix equal parts vermiculite, sterile sand and peat moss in a bucket or wheelbarrow and fill sterilized flats for seed starting.


Combine vermiculite with equal parts of peat moss and pasteurized garden loam -- garden soil baked in a 250 degree Fahrenheit oven for 30 minutes or purchased as bagged "garden soil" at a nursery -- to create potting soil for container plants.


Cover seeds sown directly outdoors with vermiculite instead of soil when your garden soil is heavy and tends to crust or clump.


Dig 2- to 3-inch layer of vermiculite into the planting area of a garden row to improve drainage or increase moisture and nutrient retention. Because it takes up to one-third soil volume of vermiculite to significantly change the quality of the soil, it can be costly to amend an entire garden with vermiculite. Work the product only into the planting zone.


Top-dress tender seedlings with a light layer of vermiculite in the garden or in pots as a mulch to help them hold water and reflect heat around the plants. This is most effective in areas protected from wind, as the lightweight material easily blows away.


Pack vermiculite around bulbs and rhizomes of plants such as tulips, narcissus, begonia, dahlia, canna or caladium that you lift and store for the winter to draw moisture away from the bulbs and prevent rot.