DiatoShield is a product that has a few different uses around plants. The main reason we find customers buy it is as a top dressing for media. It forms a barrier against crawling insects that live in and around the soil. Diatomacous earth is sharp in its structure and it is very abrasive to bugs. They have a hard time moving through it without being punctured and killed. It is good against pests such as scarid fly, fungus gnats and thrips. Ideally, a 1cm layer is best on each pot to ensure a thick enough obstacle to prevent the insects getting through. After application, do not water through the dressing as it will seriously reduce its effectiveness. In this situation, water from the bottom to maintain its integrity.
DiatoShield (or Granulated Calcined Diatomaceous Earth) is great for use as a soil improver too. It helps prevent compaction, increases aeration and drainage as well as improving soil structure. If in use in pots, it will also help prevent water logging. Suitable for use indoor and outdoor gardening, offering similar benefits in both. Follow the manufacturers instructions for specifics on mix rates and the like.
Alternatives to DiatoShield
At Straight Up Hydroponics, the closest we have to DiatoShield is regular perlite. It will give all of the soil improvements when in use as a mixer. As a top dress, it may not be as effective as DiatoShield against insects, but will still act as an obstacle. We keep it in a cost effective 100L bag if you need to cover a large number of pots. You can find it on our website by clicking here. We also have a variety of pesticides, traps and treatments for diseases and insects if you need something else. You can browse through what we have by following this link.