Vermiculite and perlite look similar and both retain moisture and both provide aeration for the roots of plants, however, they are indeed different. Let’s see what’s the difference between vermiculite and perlite.
What is Vermiculite?
Vermiculite is an aluminum silicate, it is mined out of the ground and then heated and expanded into a soil additive that mainly increases water retention and nutrient retention levels in the soil. Vermiculite’s water-holding capability makes it perfect as an anti-caking agent in dry pesticides and fertilizers.
Vermiculite is best used for water-loving plants that need their soil to stay moist at all times. Add a healthy scoop of vermiculite to the potting soil of plants that like lots of water.
What is Perlite?
Perlite is a porous material made from volcanic rock, which is heated and crushed until it explodes in order to transform the rock into small white pieces. It has medium water retention ratings and low nutrient retention ratings. Perlite is used to be added to soil mixes to improve the drainage capability of both soil-based and soilless potting mixes.
Perlite helps insulate the plant’s roots from extreme temperature fluctuations. It’s also used as a protective coating on pelleted seeds. Perlite is lightweight, odorless, clean, and easy to handle. It has a pH of 6.6 to 7.5. Add perlite to your soil for plants that need their soil to dry out between waterings, such as cacti or succulents.
Vermiculite vs Perlite:
Vermiculite:
- Vermiculite is great for seed starting or blending your own custom potting soil mix.
- Helps to lighten and loosen heavy, compacted soil types.
- Vermiculite has a neutral pH level.
- Helps soil retain moisture and gives plants nutrients.
- Mixes easily and well with soil.
- Clean, sterile, non-toxic, and odorless.
Perlite:
- Perlite is great for seed starting mixes and blending your own custom potting soil mix.
- Helps lighten and loosen heavy, compacted soils.
- White granular pieces that contain about 6 percent water.
- Neutral pH
- Holds nutrients 3-4 times its weight in water.
- Clean, sterile, odorless, and non-toxic.
- Won’t rot or mold.
- Can float to the top of potted plants due to their lightweight.
Vermiculite or Perlite, Which One to Choose for Your Garden?
Vermiculite is a better water holder. If you want to increase the water-holding capacity of your potting mix, adding vermiculite is preferable. Although both perlite and vermiculite work to improve water retention in dry potting soil, vermiculite has a higher water holding capacity than perlite.
Perlite is better than vermiculite at improving aeration or air porosity. When either perlite or vermiculite are used exclusively, vermiculite is better for germinating seeds and perlite is better for establishing cuttings. As the sole growing medium in a hydroponic setting, perlite is more suitable, although a mixture of the two is ideal.
Perlite is better for cuttings due to its high macroporosity. Cuttings tend to benefit from having access to lots of oxygen as well as water.
Perlite/Vermiculite Mix Ratio for Rooting/Cutting/Seeds
| Application | Plants | Peat or Perlite | Vermiculite | Grade |
|---|---|---|---|---|
| Seed Starting | Fine Seed | 0% | 100% | 2-4mm |
| Quick Germination | Large Seed | 0% | 100% | 3-6mm |
| Seed Starting | Fine Seed | 50% | 50% | 2-4mm |
| Slow Germination | Large Seed | 25% | 75% | 3-6mm |
| Softwood Cuttings | On Open Beach | 80% | 20% | 3-6mm |
| Under plastic | 50% | 50% | 3-6mm | |
| Transplant Mixes | Block Mix | 80% | 20% | 3-6mm |
| Seeding Wedgemix | 80% | 20% | 2-4mm | |
| Bedding Plants | 75% | 25% | 3-6mm | |
| Potting Mixes | Vegetable Plants | 60% | 40% | 2-4mm/ 3-6mm |
| House Plants | 75% | 25% | 3-6mm | |
| Hanging Baskets | 50% | 50% | 3-6mm | |
| Nursery Stock | 80% | 20% | 3-6mm |
