BioGranules Results Summary

CharGrow, LLC manufactures biochar-based soil inoculants in Mills River, North Carolina. One of our most important products is our CharGrow ® BioGranules ™ (also known as Original Concentrate). This proprietary formula evolved out of our work with organic potting soils, and the need to provide high concentrations of beneficial organisms in “peat lite” growing media.

Field trials with CharGrow ® BioGranules ™ (BG) have shown better plant productivity when BG is added at 2-3% by volume (in growing mixes) or 15 – 20 lbs. per acre in row crops.  Buy Now

Factors that have contributed to increased plant growth when BG is added to soils include:

  • Increased plant health due to colonization of roots by beneficial organisms
  • Increased cycling of soil nutrients when the transplant is established in the field
  • Better utilization of nutrients from cover crops that were tilled in prior to planting
  • Earlier plant maturity (earlier flowering & fruit set)
  • Greater yield at first pick and through the growing season
  • Increased resistance to drought

Download this BioGranules-Results-Summary as a PDF file (~6 MB)



chargrow biogranules trail results summary eggplant

Eggplant starts – with and without BioGranules

Photo Courtesy of Ellen Polishuck – Potomac Vegetable Farms 2016

“We found that using the BioGranules in our greenhouse mix consistently produced better, sturdier transplants.”
Ellen PolishuckPotomac Vegetable Farms


Sweet Corn

The earliest replicated trials for BG were conducted on organic sweet corn in Ohio. This occurred during a drought year. The grower reported that the BG treated soil was holding more water and beneficial fungal activity was visible above ground on cover crop residue. When applied at 10 lbs BG per acre, (applied down the row) the grower achieved an average 20% increase in yield.

In this trial, microbial populations were assessed at the beginning of the season (just before planting) and then again at time of harvest. Results indicated the following:

17% Increase in Bacteria
43% Increase in Total Fungi
66% Increase in Flagellates
206% Increase in Amoebae
522% Increase in Mycorrhizal Fungi

Based on these results, field trials were repeated on sweet corn at Virginia Tech. Yields increased by 10 -15% in these plots.

In NJ, corn test plots demonstrated a 100 bu. per acre yield (with a 20% reduction in fertilizer use) when BG was applied at 20 lbs per acre

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Sweet corn trial without CharGrow BioGranules

without BioGranules

Sweet corn trial with CharGrow BioGranules

with BioGranules

Virginia Tech

Tomato Transplants

In addition to corn research, a preliminary study on tomatoes was added at Virginia Tech, which resulted in 25% larger transplants.

Based on this finding, replicated trials were continued over 3 growing seasons. In these studies, product was used at 2.5 cups per 5 gallons of potting soil (3% by volume). This rate increased end of season yield by as much as 20 %. In addition, first pick was earlier and first pick yield averaged 50% greater than non-inoculated plants over 3 years of replicated trials.

CG-inoculated transplants were greener and approximately 25% taller at field setting than control plants. Shortening the time required to produce healthy transplants reduces production costs.

Earlier fruiting yield in CG-inoculated plants was increased by 50%, compared to non-inoculated plants. Earlier fruiting normally results in increased profits, especially for growers in northern short-season climates.

Earlier fruiting did not compromise yield potential of CG-inoculated plants, which remained vigorous throughout the growing season. This “stay green” effect resulted in high total tomato yield and would permit extended multiple harvests in areas with long- growing seasons.

Virginia Tech tomato transplant trials with and without CharGrow BioGranules

L: Control (no BG) | R: BG-inoculated (2.5%)

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North Carolina

Tomato Transplants

To further verify the VA Tech results, short-term greenhouse trials were conducted at an organic farm in western North Carolina. Results in this trial showed that soil biology and growth effects of the BG were visible at 4 1⁄2 weeks from seeding. Plant biomass was greater when rates were increased from 1 cup to 2 cups of BG per 5 gallons of potting soil (roughly equivalent to 1% and 2 % by volume). In later trials, if was found that biomass was greatest when used at 3% by volume.

The effect of addition of CharGrow BioGranules beneficial soil microorganisms on tomato transplants

(plants shown are 4 1/2 weeks old)

chargrow biogranules north carolina tomato transplant trial without

Fafard Organic Potting Soil

1 cup BioGranules mixed into 5 gallons of Fafard Organic Potting Soil

2 cups BioGranules mixed into 5 gallons of Fafard Organic Potting Soil

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University of Florida


To ascertain the effects for CharGrow BioGranules (BG) on nursery stock plantings, research was conducted at the University of Florida on Vinca. In this study BG was applied at 10 and 20 lbs. per cubic yard of container media.

The results of these trials demonstrated longer-term color retention and reduced nutrient runoff measured by soluble salts and nitrate-N analyses. When used at 20 lbs. / yd of growing media, BG significantly improved growth and soil nitrate-N retention. It was also noted that BG would likely allow growers to lower their controlled release fertilizer rates. This can reduce nutrient runoff to the environment, an added benefit.

12 week-old Vinca Pacifica (L: with BG, R: two plants without)


In this trial, Rosa-sinensis ‘President’ was selected because its growth and color are excellent indicators of nitrogen concentrations in the soil. The fertilizer used in this trial was a 3-4 month Osmocote product (19-6-12) that is typically exhausted well before 3-4 months under south Florida conditions.

Researchers concluded that when incorporated at 20 lbs/yd, BG significantly improved hibiscus growth and soil nitrate retention over that of untreated controls.

” Product C (BG) at 20 lbs/yd appeared to reduce the need for high rates of Osmocote, since the lowest rate (20% less) performed as well as the higher rates with respect to all soil nutrient and plant quality parameters measured. ” They also explained that this should result in reduced nutrient runoff into the environment, an added benefit.

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chargrow biogranules university of florida hibiscus trial

BioGranules significantly improved hibiscus (Rosa-sinensis ‘President’) growth and soil nitrate retention in 3-4 month trials