Proper vermiculite to soil ratio

Updated February 21, 2017

Horticultural vermiculite is valuable to backyard gardeners and landscapers alike. Vermiculite not only promotes soil aeration and drainage, it also improves seed germination, and provides an optimal environment for storage of tubers, corms and bulbs. Since vermiculite can be used in a variety of applications, it is important to learn the proper vermiculite to soil ratio that is most beneficial for different gardening needs.

Vermiculite and Seed Germination

Vermiculite hastens germination, helps more seeds to germinate successfully and generally cuts down on the watering required during the germination process. In some cases, vermiculite may be used alone, but it is most often mixed half and half with either soil or peat.

Vermiculite and Soil Conditioning

Conditioning heavy, sticky or sandy soil with horticultural vermiculite aerates the soil and allows it to breathe. When adding vermiculite to flower and vegetable gardens, the most beneficial vermiculite to soil ratio is about half soil and half vermiculite. The resulting soil mixture will efficiently hold the necessary water and air needed for optimal plant growth.

Vermiculite and Houseplants

The remedy for packed flowerpots is the same as for conditioning garden soil, and you can even buy vermiculite premixed with potting soil in your garden supply store. If you choose to mix the soil yourself, use half soil (or peat) and half vermiculite to aerate the soil and keep it consistently moist. Potted plants will enjoy a growth boost, and less watering will be required.

Vermiculite and Lawns

Because vermiculite helps the germination process, it is an ideal additive to new lawn beds. Proper use of vermiculite will produce a faster growing, denser lawn that will not scorch as easily during dry spells. For new lawns, mix three cubic feet of vermiculite with each 100 square feet of soil. Once the area is seeded, cover it with 1/4 inch of vermiculite.

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About the Author

Melissa Lewis has worked as a freelance writer since 2004, gaining much of her experience by working in the marketing/PR field. She writes for various websites, specializing in the areas of marketing, home improvement, cooking and pets. Lewis studied English at the University of Wisconsin-Madison.