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Frassilizer 3-4-2 (28oz)

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Complete, all purpose, organic 3-4-2 NPK fertilizer

Great for fruit trees, lettuce, legumes that benefit from higher Phosphorus. Phosphorus is needed for root development, stem formation, and fruiting in summer vegetables like tomatoes, peppers, eggplants, squash, melons, and cucumbers.

Contains 100% pure mealworm frass, the natural and organic waste from raising mealworms. Frass consists of the dry excrement of the mealworm together with their shedded exoskeletons and a small amount of leftover food (wheat bran and carrots). 

Frass stimulates beneficial soil microbial activity

Most people don't know much about the microbes in their soil. It turns out that many professional farmers are just starting to learn about them too, as research in the field is coming to light. Microbial activity near the roots of plants can help with the availability of both nitrogen and phosphorus as well as the suppression of pests and pathogens, and more.

Strengthens plant's natural defenses

Frassilizer contains chitin coming from the shedded exoskeletons of the mealworms as they were growing. Scientific research has shown the following benefits from chitin:

  • Chitin helps with the uptake of nitrogen as well as improving the absorption of calcium, phosphorus, and magnesium.
  • Chitin can boost the plant's immune system. It does this by tricking the plant into thinking it is getting attacked, even though it isn't, which triggers the plant to toughen up.
  • Chitin causes the plant to produce a chitinase enzyme, which can make harmful insects "itchy."
  • Chitin boosts the beneficial microbes in the soil, which are essential for breaking down organic matter into food for the plant's root systems. 

Compostable bio packaging (no plastics!)

All of the packaging that comes with our products can be either recycled or composted. The box used in shipping is made from recycled carboard and itself can be recycled just about everywhere. If you don't want to or can't recycle it, use it in the garden as a weed barrier or mulch. The bag itself is made from bio-based materials. It will break down in a standard compost pile and can also go into your green waste curbside bin, as it complies with the ASTM D6400 standards used by municipal and industrial facilities

1% for the Planet

We support organizations working to reduce the harmful effects of plastics on our environment. We pledge to give 1% of gross sales to certified non-profit organizations doing work to reduce plastic pollution in a variety of ways. We need to look at an "all of the above" approach to this problem that includes everything from finding alternative materials, to better recycling, to innovative methods to break down plastics back into organic materials, and more.

Easy to apply

Frassilizer can be applied either as a dry fertilizer directly to the soil or you can mix with water to create a foliar spray. Below find the instructions for application as a dry fertilizer:

Frequency of application:

  • Apply Frassilizer once a month during the growing season.
  • For fruit trees and shrubs, apply fertilizer twice a year, once in the spring and once in the fall.

Amount of Frassilizer to apply:

  • The amount of Frassilizer to apply will vary depending on the type of plant and the size of the plant. 
  • For mature plants ...
    • For vegetable gardens, apply 3-20 pounds of Frassilzer per 100 square feet per year. 
    • For fruit trees and shrubs, apply 3-6 pounds of Frassilizer per 100 square feet per year. 
  • For transplants ...
    • For vegetables (6-packs or 4" pots), add anywhere from a pinch to 1/8 cup
    • For trees & shrubs (1 gallon to 15 gallon containers), add anywhere from 1/4 cup to 1 cup
  • For lawns, apply 3-20 pounds of Frassilizer per 100 square feet per year depending on how fast and thick you want the grass to grow.

How to apply: 

  • Do not apply Frassilizer to plants that are stressed.
  • Apply dry Frassilizer to the soil around the base of the plants, not directly on the leaves. Lightly work it into the soil
  • Water the Frassilizer into the soil after application.
  • It’s better to apply less Frassilizer than to provide too much. Err on the side of caution.

Learn more from the Utah State University extension

No odor

Unlike manure from poultry or ruminants, mealworm frass has little to no odor. Some people say it smells faintly of cut grass; others like cocoa. Share with us what you think it smells like in a product review or simply Contact Us.


  • Store Frassilizer in a cool, dry place.
  • Keep Frassilizer out of reach of children and pets.
  • Do not store Frassilizer in direct sunlight or in a humid environment.
  • Do not store Frassilizer in an area where it can come into contact with food or water.

ONLY AVAILABLE IN OR, WA, CA, and ID (other states coming soon)


You may return new, unopened items within 60 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).