Whether you have done gardening for a while or just taken your first step in this lovely passion, you may have come across some issues on your plant's growth. When plants don't grow well, there are several factors: lack of nutrients and air ventilation in the soil, lack of water or too much water in the soil, the humidity of the environment, wrong soil used and lack of sunlight. While you can't change the humidity condition for outdoor gardening, you can adjust the soil content to meet favorable conditions for your plant to grow better. Perlite and Vermiculite could help you to improve the soil structure for your plants.
So, what's perlite and vermiculite?
Perlite is formed when obsidian gets in contact with water, forming a type of volcanic glass with high water content. When heat is applied, it puffed up into little white balls that look like styrofoam. These tiny pebbles are lightweight, odorless and have a ph of 6.6 to 7.5. You can place a small portion of perlite (depending on how much soil you used) into your potting soil and mix it well before planting. It helps to improve soil aeration, making the soil porous. It also provides a great drainage system and oxygen access for your plants’ roots. Perlite is best used when you have plants such as cactus or succulents in your garden that require soil to dry out completely between watering.
Vermiculite is made from compressed brown dry flakes of aluminum-iron magnesium silicate mineral. When heat is applied, it expands into shaped pellets that are composed of multiple layers of thin silicate plates. When water is used with vermiculite, it becomes spongy and forms a worm-like shape. It is odorless, non-toxic and has a ph of 7.0. You can mix half of the potting soil and half of the vermiculite for your flowering plants such as roses and tomatoes. This allows quick absorption of nutrients such as potassium and calcium in the soil, promoting strong root spread. However, if too much vermiculite is used, it will absorb too much water and doesn’t aerate the soil properly, reducing the amount of oxygen circulating in the soil. Your plant may suffer from root rot if it is not suitable in damp soil. Hence, it's important to research the amount of vermiculite your soil needs for your plants.
Which one should I use in my garden?
To sum up what we have covered, Vermiculite helps to retain moisture in the soil while Perlite will add drainage to the soil that it’s mixed with. Some people use a vermiculite mix for seed-starting and a perlite mix for growing potted plants. It is also possible to mix both but careful research is required to make sure that your plants grow properly.
In most situations, perlite can be used to eliminate soil surface crusting and puddles. It is perfect for loosening clay soil and maintaining soil temperature too. If you are shifting your seedlings into separate pots, perlite can help to prepare your soil with great drainage and aeration.
For vermiculite, it could act as a permanent soil conditioner and won’t break down in your soil. As water enters the soil, vermiculite will hold water in the soil and releases moisture when the soil starts to dry up. If you plan to develop strong seedlings in your seed trays, vermiculite can retain moisture so that you don't have to water them much.