Big Foot 4oz Mycorrhizae Granular

Big Foot 4oz Mycorrhizae Granular is a soil amendment that delivers fresh mycorrhizal spores alongside a blend of biochar, worm castings, kelp, azomite, and humic acid. It is made in the USA by a brand with 35 years in the mycorrhizae industry, and it applies at transplant or during soil mixing to support root establishment in container and in-ground growing environments.

Big Foot 4oz Mycorrhizae Granular Specifications

Physical dimensions and package details drawn from supplier data. The 4 oz size is the entry-level container in the Big Foot Granular line, suited for small-scale transplanting or trial use before committing to a larger bag.

Why Choose Big Foot 4oz Mycorrhizae Granular

Big Foot Granular stands out in the mycorrhizae additive category because it combines live spores with a complementary set of soil-building components in a single product. Rather than purchasing mycorrhizal inoculant separately from biochar or kelp, growers get a pre-blended granule that addresses several root-zone factors at once.

• Fresh spore production: Big Foot emphasizes that its mycorrhizal spores are produced fresh, which matters because spore viability decreases with age and improper storage. The brand has been producing spores from the Amaranthus Family for over 35 years.
• Multi-ingredient blend: The granular formula includes biochar for moisture and nutrient retention, worm castings as a slow-release biological input, kelp for micronutrient support, azomite for trace mineral supplementation, and humic acid to improve cation exchange capacity in the root zone.
• Made in the USA: Production is domestic, which the brand notes on its packaging and in product documentation.
• Two application methods: The granular form can be blended directly into potting mix before planting or applied to the transplant hole at the moment of transplanting. Either method puts the spores in direct contact with new root tips where colonization can begin quickly.
• Entry-level size: The 4 oz package is useful for growers who want to test mycorrhizal inoculants on a small number of plants before scaling up. It fits into existing soil prep workflows without requiring bulk purchase.

If you are also supplementing with a dedicated root stimulant, pairing Big Foot Granular with a liquid product like Advanced Nutrients Tarantula (a liquid mycorrhizae and bacteria formula) can cover both granular soil application and liquid reservoir feeding in hydroponic or hybrid setups.

Best Uses for Big Foot 4oz Mycorrhizae Granular

This product is classified under Nutrients & Additives > Additives > Roots, and its application is specific to soil and soilless media where root colonization is possible. Mycorrhizal inoculants are not effective in fully hydroponic (water-culture) systems because the fungal symbiosis requires a solid substrate for spore germination and hyphal development.

• Transplanting into containers: Apply a small amount of granules directly into the planting hole before setting the root ball. This places spores in contact with roots immediately.
• Mixing into new potting soil: Blend the granular amendment into dry or lightly moistened substrate before filling containers. This distributes spores throughout the root zone rather than concentrating them at one point.
• Raised bed preparation: Incorporate into raised bed soil at planting time for vegetable gardens, herbs, or flowering plants.
• Coco coir or peat-based mixes: The granular form works in any porous, organic or mineral substrate that supports hyphal growth, including coco-perlite blends.
• Re-potting established plants: When moving a root-bound plant to a larger container, applying granules to the new soil encourages fresh colonization in the expanded root zone.

Growers who want additional organic input alongside the mycorrhizae may also consider Earth Juice Hi-Brix Molasses, which provides carbohydrate support to microbial populations in the root zone when used together with biological soil amendments.

Usage Guidelines

The canonical product documentation describes two application approaches: mixing with soil before planting, or applying at the time of transplanting. No specific gram-per-gallon dose rate is published in the available documentation for this SKU. General industry guidance for mycorrhizal granular products in container growing is provided below as a reference, but growers should follow label directions printed on the physical package, as rates can vary by crop type and container size.

• At transplant: Place a small pinch of granules (approximately 1 teaspoon per gallon of container volume is a common starting rate for mycorrhizal granulars) into the planting hole or mix into the surrounding soil before backfilling around roots.
• Soil blend: Mix into dry substrate at the manufacturer’s recommended ratio before filling containers. Ensure even distribution rather than concentrated pockets.
• pH range for mycorrhizal activity: Mycorrhizal fungi generally function optimally in soil pH between 5.5 and 7.0. Check substrate pH before application.
• Avoid fungicides: Do not apply in combination with systemic fungicides, which can inhibit or kill the mycorrhizal spores and prevent colonization.
• Storage: Store in a cool, dry location away from direct sunlight to preserve spore viability.

Sources & Further Reading