Biosolid vs. Poultry Compost: What’s Best for Your Missoula Garden?

Biosolid vs. Poultry Compost: What’s Best for Your Missoula Garden?

Biosolid vs. Poultry Compost: What’s Best for Your Missoula Garden?

If you’re serious about improving your soil in Missoula, compost is one of the best tools you can use — but not all compost is created equal. Two of the most commonly used types are biosolid compost (made from treated human waste) and OMRI-certified poultry compost. Here’s what you need to know before you spread it across your garden or landscape.

 

 

🧪 What Is Biosolid Compost?

Biosolids are the treated organic solids left over from municipal wastewater processing. They’re heat-treated and processed to kill pathogens, then often sold or distributed as a soil amendment.

Pros:

  • High in nitrogen and phosphorus

  • Readily available

  • Affordable in bulk

Cons:

  • May contain heavy metals, pharmaceuticals, or PFAS ("forever chemicals")

  • Not certified organic

  • Often unsuitable for edible gardens

  • Local controversy around safety and application

 

 

🐓 What Is OMRI-Certified Poultry Compost?

Poultry compost is made from chicken or turkey manure mixed with bedding material like straw or sawdust. When OMRI-certified, it meets the standards for use in organic farming.

Pros:

  • OMRI-listed = approved for organic gardening

  • Excellent for vegetable gardens and raised beds

  • High microbial activity = better soil health

  • Safe for kids, pets, and food crops

Cons:

  • Higher cost than municipal biosolids

  • Slight odor when first applied (fades quickly)

 

 

🔍 Side-by-Side Comparison

Feature

Biosolid Compost

OMRI Poultry Compost

Nutrient Content

High nitrogen & phosphorus

High nitrogen & organic matter

Safety for Food Gardens

❌ Not recommended

✅ Certified for edible crops

Organic Certification

❌ Not organic

✅ OMRI-listed (USDA organic)

Environmental Concerns

May contain trace contaminants

Natural & microbially active

Odor

Mild, chemical or musty

Farm-like but fades fast

Cost

Lower

Slightly higher, better quality

 

 

🌱 Our Recommendation for Missoula Gardeners

If you're planting vegetables, fruits, or anything edible, stick with OMRI-certified poultry compost. It's safer, cleaner, and better for long-term soil health. For lawns or ornamental beds where organic certification isn’t a concern, biosolid compost may be an economical choice — but be mindful of where it comes from and what’s in it.

At Mammoth Lawn & Landscape, we offer premium poultry compost delivered to your door — whether you need a full yard or just a small load for your raised beds.

 

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