C20 Soil Builder by Precision Organics – 40 lb Bag
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C20 Soil Builder by Precision Organics is a granular carbon food source for soil microorganisms, including bacteria and fungi. Made from grain by-products bound with molasses, it feeds soil biology to support soil structure and nutrient cycling. This 40 lbs. bag is suitable for lawns, gardens, new sod, overseeding, and compacted landscape soils.
Coverage at a glance: One 40 lbs. bag treats 1,000–4,000 sq ft at the overview rates below. Spread evenly with granular turf equipment and irrigate after application. Garden rates differ between the overview and bag label; see the garden guidance below before choosing a rate.
What C20 does for your soil
- Feeds existing soil biology: Provides a carbon food source for soil bacteria and fungi. It is not a microbial inoculant.
- Supports soil structure: Biological activity helps soil particles form aggregates, creating pore space for air, water, and roots.
- Supports nutrient cycling: Soil microorganisms help release nutrients from organic matter.
- Fits several landscape uses: Application rates are available for established turf, new sod, overseeding, flower beds, vegetable gardens, and tree rootzones.
Choose your application rate and bag coverage
The rates below are provided in the manufacturer's C20 Soil Builder overview. Coverage is calculated for one 40 lbs. bag; follow the current package label for use directions.
- 10 lbs. per 1,000 sq ft, covering 4,000 sq ft per bag: Seasonal microbial aeration, salt mitigation, hydroseeding, overseeding, and new sod installation.
- 20 lbs. per 1,000 sq ft, covering 2,000 sq ft per bag: Lawn rejuvenation for compacted soil, tree rootzone restoration, flower beds, and landscape or vegetable gardens. See the garden-rate clarification below.
- 40 lbs. per 1,000 sq ft, covering 1,000 sq ft per bag: Soil remediation for severely compacted or construction-damaged soils.
Garden-rate clarification: The 2026 product overview lists 20 lbs. per 1,000 sq ft for flower beds and landscape or vegetable gardens. The linked bag label lists 2 lbs. per 100 sq ft (equivalent to 20 lbs. per 1,000 sq ft), or 2 lbs. per 1,000 sq ft. These are different rates, not interchangeable coverage claims. Follow the current label on your bag and confirm the appropriate garden rate with Precision Organics if the directions are unclear. At the lower label rate of 2 lbs. per 1,000 sq ft, calculated coverage is 20,000 sq ft per 40 lbs. bag.
Planning your order: Divide your treatment area by the coverage at your selected rate, then round up to whole bags. For example, a 4,000 sq ft lawn requires one bag at the 10 lbs. rate or two bags at the 20 lbs. rate.
How to apply C20 Soil Builder
- Select the rate that matches your intended application.
- Spread evenly across the soil surface using granular turf equipment. Apply when temperatures are above freezing.
- Irrigate after spreading to activate the product. For new sod, the manufacturer recommends applying beneath the sod during installation.
Compatibility and storage
C20 needs oxygen. Do not apply to soils with standing water or continuously saturated soils. Do not cover treated areas with impervious barriers such as water bags or landscape fabric. The manufacturer identifies broad-spectrum fungicides, biocides, and fumigants as exceptions to compatibility with most soil treatments. Store in a dry location away from pests.
Tree and shrub cautions from the bag label: Do not apply to plants that are already dead or dying. If a tree, shrub, or plant is significantly stressed, with signs such as dieback, leaf drop, or wilting leaves, but is not dead or dying, resolve the cause of the stress before applying C20 at half rate. Remove landscape fabric before treatment. Do not use C20 beneath a water bag: the label directs applying outside the water-bag perimeter.
Frequently asked questions
Is C20 Soil Builder a fertilizer or a microbial inoculant?
C20 is a carbon food source for soil microorganisms rather than a direct plant nutrient additive. It feeds existing soil biology; it does not add a microbial inoculant and is not a replacement for a soil-test-based fertility program.
How much area does a 40 lb bag cover?
A 40 lb bag covers 4,000 sq ft at 10 lb per 1,000 sq ft, 2,000 sq ft at 20 lb per 1,000 sq ft, or 1,000 sq ft at 40 lb per 1,000 sq ft. Choose coverage based on the rate for your intended use, not the maximum coverage alone. The bag label also lists a lower garden rate; see the garden-rate clarification above.
Can I use C20 in vegetable gardens and flower beds?
Yes. Both the overview and bag label include these uses, but their garden-rate directions differ. The overview lists 20 lb per 1,000 sq ft. The linked bag label lists 2 lb per 100 sq ft or 2 lb per 1,000 sq ft. Follow the current label on your bag and confirm the intended rate with Precision Organics if unclear.
Does C20 need to be watered in?
Yes. Irrigate after application to activate the product. The manufacturer notes that watering releases the molasses binder and reduces wildlife attraction.
Can I apply C20 when installing new sod?
Yes. The manufacturer's overview lists new sod installation at 10 lb per 1,000 sq ft and recommends applying beneath the sod during installation. Follow the current package label.
