Vermiculite is a type of clay that expands when heated. Chemically it is a hydrated magnesium iron aluminum silicate mineral It is used to promote faster root growth and give quick anchorage to young roots.
Vermiculite can absorb three to four times its weight in moisture. It also attracts nutrients like magnesium, calcium, and potassium. It holds more moisture and works more like a sponge.
Uses of Vermiculite in Garden
Exfoliated vermiculite that is generally used in gardening, benefits the plants in many ways by providing good aeration to roots, moisture, and nutrient retention. Vermiculite is sterile, lightweight, and has a neutral pH.
1. Soil enrichment
If the potting soil is compact and lacks good drainage use vermiculite up to one-half the volume of the soil and mix it. It provides good aeration and moisture retention. It also helps to maintain plant vigor.
2. Planting cuttings
Planting cuttings in vermiculite promotes good root growth and provides anchorage to the cutting. Vermiculite can be used plainly or can be mixed with soil. The success of root cuttings is higher in vermiculite than in any other planting media.
3. Seed germination
Vermiculite is a medium for root germination. If it is used plainly, then a weak fertilizer solution should be added when the first true leaves appear.
4. Container gardening
Vermiculite is a good addition to the potting mix for outdoor as well as indoor plants. It holds moisture well, therefore you don't need to water the plants very frequently.
5. Lawn seeding
Vermiculite can be spread on the lawn after seeding at a proportion of 3 cubic feet for every 9 square meters. After applying vermiculite, it must be watered. It protects the seed from heat, releasing moisture, thus promoting successful germination.
4. Root crop storage
The dried bulbs or tubers can be stored in vermiculite. Vermiculite absorbs extra moisture and prevents the bulbs from rotting.
Vermiculite is a good mulching material as it good holding moisture. Add a few inches of vermiculite on the topsoil to avoid water loss from evaporation.
Vermiculite is commonly used in hydroponics. It releases moisture when the plant needs it. It also promotes better absorption of nutrients by the plants.
Pros and Cons of Vermiculite
- Good water retention
- Sterile and neutral pH
- Provides good aeration to the soil
- Improves root growth promotes rapid growth
- Increases nutrient retention
- It is not a renewable resource
- Vermiculite is a bit costly
- Can retain excess moisture
Because vermiculite can be quite expensive, you can also substitute these materials instead: coir, cocopeat, peat moss, sawdust, wood chips, and shredded bark. These are the materials used most often as alternatives to vermiculite.
Dr. Vandana K.