Cabbage Seedling Application Trial
― Interim Report ―

Bio Charger improved seedling quality (stem thickness and rooting)

This is an interim report on a nursery trial with cabbage plug seedlings. We compared a plot in which 1 kg of Bio Charger, a microbial and amino-acid material, was added per 100 L of seedling potting mix (the “Bio Charger plot”) with an untreated plot (the “control plot”). The report is based on observations and photos after sowing on June 23 (on July 2, July 13 and when the root balls were checked), together with three analyses of Bio Charger: fertilizer components, amino acids and microbial community.

The provisional finding so far is that the Bio Charger plot has thicker hypocotyls (stems) and denser root balls, giving seedlings the shape you want for transplanting cabbage. The initial concern, “legginess and weak growth from over-application,” was not clearly observed in the Bio Charger plot. However, stem thickness is only a visual estimate from photos (±20–30%), and seedling quality at the nursery stage is a separate question from performance at heading. A final judgment will wait for measured stem diameters and follow-up from transplanting through head formation.

Provisional conclusion: Bio Charger is improving seedling quality (stem thickness and rooting) and outperforms the untreated plot. The optimal application rate will be confirmed by “measured stem diameter” and “field performance through head formation.”

Purpose and conditions

Component analyses by third-party laboratories

The third-party certificates below were issued under the former name “BioPixie.” In this report the material is referred to as Bio Charger, and the certificate names are noted only where relevant.

2.1 Fertilizer components

Fertilizer analysis by the Environmental Research Center (Ibaraki, Japan). Sample name on certificate: BioPixie T; sample no. 23110035; reported 2023/05/15.

Key point: With 6.3% nitrogen and a C/N ratio of 6, this is not just a microbial inoculant but an organic fertilizer whose nitrogen acts readily. An EC of 4.11 mS/cm is somewhat high for the material on its own.

2.2 Amino acid composition

Japan Food Research Laboratories. Sample name on certificate: BioPixie; reported 2023/07/04. Main amino acids shown (total approx. 37.7%).

Key point: Total amino acids are very high at about 38%, led by glutamic acid and aspartic acid. Plants can absorb these directly, and they strongly promote vegetative growth (stem and leaf extension).

2.3 Microbial community (16S rRNA analysis)

Microbial community analysis of Bio Charger (certificate name: BioPixie), December 2024, by 16S rRNA long-amplicon sequencing. At genus level Bacillus accounts for about 70.7%, making it a Bacillus-dominated material.

Key point: B. subtilis and B. velezensis are known plant growth-promoting rhizobacteria (PGPR), reported to produce auxin- and cytokinin-like substances, promote root development and suppress disease.

Main components added per liter of potting mix

Estimated main components added per liter of potting mix when 1 kg of Bio Charger is added to 100 L (= 10 g/L).

Reference: The nitrogen guideline for the starter charge in typical plug potting mixes is roughly 100–200 mg/L. The nitrogen load here (equivalent to about 630 mg/L) is 3–6 times that, and with a C/N ratio of 6 and mostly amino-acid nitrogen that breaks down quickly, it works strongly from the start. As discussed below, however, whether this shows up as legginess must be judged from actual growth.

From germination to transplant readiness

Sown June 23. By July 2 (9 days later), true leaves were starting to emerge from the cotyledons, and germination and early growth were generally good. By July 13 (20 days later), true leaves had unfolded and growth had advanced, and differences between trays and between plots were becoming clear. White roots had spread throughout the cells, reaching the stage where seedlings are ready for transplanting. As this was a summer nursery in high temperatures, growth was fast.

Plot comparison at this stage

Comparison at this stage based on photos, including close-ups taken when checking the root balls. Stem thickness is a visual estimate from photos.

Note: Plot identification (which plot received Bio Charger) is based on photo labels provided by the trial operator. With Bio Charger = green hypocotyl; untreated = purple to reddish hypocotyl.

📷 Root development in the cells (photo comparison)

Whole-tray comparison (July 23)

Discussion at this stage

• Seedling quality favors the Bio Charger plot. Hypocotyls are thicker and root balls denser, close to the ideal cabbage transplant that establishes well and resists toppling. A thick hypocotyl and strong rooting are clear strengths in cabbage seedlings.
• No “legginess or weak growth from over-application” so far. If anything, the Bio Charger plot is more compact and sturdy, and the initial concern (legginess from high nitrogen) has not materialized. Hormone-like effects from the microbes (PGPR), plus amino acids and moderate nitrogen, may have contributed to root development and a sturdier hypocotyl.
• The nutrient load is high, but it has not shown up as harm in the seedlings. The estimated nitrogen load of about 630 mg/L is several times the usual guideline, yet the white, healthy roots indicate no acute salt injury or clear weakening.
• But a “good seedling” and a “good head” are different questions. Cabbage forms its head from a single terminal bud. Vigor at the nursery stage could still come back at heading as the effects of excess nitrogen: overgrown outer leaves, delayed heading, loose heads or a higher risk of soft rot. This cannot be judged from the look of the seedlings alone.

Accuracy of figures and scope of evaluation

• Stem thickness is not yet confirmed. The figures are visual estimates from photos, with an error of roughly ±20–30%. The direction (“the Bio Charger plot is thicker”) is consistent across multiple observations and close-ups, but the values are not final. Measurement by edge detection in images that include a ruler or coin is needed.
• The comparison is mainly a qualitative evaluation based on photos, with limited replication and sample size.
• During preparation, the analyst temporarily mixed up the plot labels and corrected the interim assessment. This report is unified on the latest labels from the trial operator (with Bio Charger = green / untreated = purple).
• Only the nursery stage has been evaluated; performance from transplanting through harvest (heading) has not.

Verification plan toward a final conclusion

• Measure stem diameter. Photograph stems next to a ruler or coin and measure both plots at several points (mean ± error) to confirm.
• Set up application-rate comparison plots. Line up rates such as none / half / one-third / 1 kg, and identify the rate closest to the quality cabbage seedling standard (stem 3–4 mm, 4–5 true leaves, a single main stem, no legginess, dense white roots).
• Late nursery management. Water a little less and ensure good light and ventilation to harden the seedlings, keeping growth strong while suppressing legginess.
• Follow-up from transplanting to heading. Record establishment, outer-leaf growth, heading timing and firmness, head weight and disease (e.g. soft rot) to judge whether “the Bio Charger plot also excels at heading, or whether excess nitrogen loosens or delays the heads.”
• Standardize records. Tabulate stem diameter, plant height, internode length, true-leaf count, branching, root-ball condition and heading data for each plot (a recording sheet will be prepared separately).

This is an interim report; the provisional conclusion will be updated based on future measurements and field follow-up.