Biofertilizer for Tubers: Application Guide for POC Formula Tuber Quality during the Tuberization Phase

Uniform, large, and dense tuber growth is the dream of every potato, sweet potato, and shallot farmer. The tuberization phase is the main determinant of harvest quantity and quality. However, this phase is often disrupted by hormonal imbalance, suboptimal nutrient availability, or environmental stress. This is where the role of biofertilizer for tubers becomes crucial. Biosolution presents POC Formula Tuber Quality, a liquid organic fertilizer (POC) specifically formulated to stimulate uniform tuberization and increase tuber weight per plant by 15–25%. This article will thoroughly discuss the application method of this POC for the tuberization phase: dosage, frequency, and timing to maximize your harvest.

Why Does the Tuberization Phase Require Specific Biofertilizer?

The tuberization phase is a critical period when plants shift energy from vegetative growth to tuber formation and filling. During this phase, the need for micronutrients and growth hormones increases dramatically. Synthetic chemical fertilizers often cannot provide balanced nutrition and may even damage soil microbiology. In contrast, biofertilizer for tubers like POC Formula Tuber Quality works naturally by:

• PGPR (Plant Growth Promoting Rhizobacteria) Consortium: These bacteria produce growth hormones such as auxins, gibberellins, and cytokinins that stimulate tuber cell division and accelerate filling. PGPR also increases the availability of micronutrients like zinc (Zn) and iron (Fe), essential for tuber formation.
• Seaweed Extract: Contains natural cytokinins and complete micronutrients that strengthen tuber cell walls, making tubers denser and less prone to hollowness.
• Humic and Fulvic Acids: Act as nutrient carriers, increase soil cation exchange capacity, and stimulate root growth. Healthy roots absorb nutrients more efficiently.

These three components work synergistically to ensure each tuber receives adequate hormones and nutrients, resulting in uniform size, optimal weight, and longer shelf life.

Application Method of POC Formula Tuber Quality: Dosage, Frequency, and Timing

To be effective, the application of POC Formula Tuber Quality must be done correctly. Here are technical guidelines based on Biosolution's recommendations:

Application Dosage

• Foliar spray method: Mix 3–5 ml of POC Formula Tuber Quality per liter of water. Spray evenly over the entire leaf surface, especially the underside where stomata are more open. This dosage is sufficient for 1 liter of solution per 10–15 square meters of land.
• Drench method (root watering): Use the same dosage (3–5 ml/liter of water) but adjust the solution volume: 200–300 ml per plant for potatoes and shallots, or 500 ml per plant for sweet potatoes/cassava.

Application Frequency

• Every 7–10 days during the tuberization phase. This phase typically begins when plants are 30–40 days after planting (DAP) for potatoes, 20–25 DAP for shallots, and 40–50 DAP for sweet potatoes. Stop application 1 week before harvest to avoid residue.
• Total applications: 4–6 times per growing cycle, depending on weather conditions and plant vigor. In extreme weather (prolonged drought or continuous rain), frequency can be increased to every 7 days.

Best Application Time

• Morning before 10:00 AM or afternoon after 3:00 PM. Avoid application during intense sunlight because leaf stomata close and the solution evaporates quickly. Ideal temperature is 20–30°C.
• Calm wind conditions to prevent spray drift to other plants or waste.
• Do not apply if rain is expected within 2 hours after spraying, as it will be washed off.

Application Tips for Various Commodities

• Potatoes: Focus spraying on lower leaves and stems. Ensure that newly forming tubers are not directly hit by the solution (can cause rot if too wet).
• Shallots: Spray evenly on leaves, especially when tubers start enlarging (30 DAP). Avoid puddling at the stem base.
• Sweet potatoes/cassava: Drench application is more effective because tubers are underground. Pour the solution around the root zone, within a 10–15 cm radius from the stem.

Mechanism of Action of POC Formula Tuber Quality in Increasing Tuber Weight

Biosolution field trial data shows that application of POC Formula Tuber Quality consistently increases yield weight per plant by +15–25% and reduces flower/fruit drop by −30%. How does it work?

1. Increased tuber cell division: PGPR produces auxins and gibberellins that stimulate cell division in tuber meristematic tissue. Consequently, there are more tuber cells, resulting in larger tubers.
2. Optimized starch filling: Seaweed extract is rich in cytokinins that trigger translocation of photosynthates from leaves to tubers. This process fills tubers with starch, making them dense and heavy.
3. Improved nutrient uptake: Humic and fulvic acids bind macro (N, P, K) and micro (Zn, B, Mo) nutrients in plant-available forms. Adequate nutrient availability during tuber filling prevents hollowness and deformation.
4. Stress resistance: PGPR also produces antioxidant enzymes and osmoprotectants that protect plants from drought stress or root pathogen attacks. Healthy plants produce quality tubers.

Advantages of POC Formula Tuber Quality Compared to Chemical Fertilizers

With biofertilizer, farmers not only get larger and denser tubers but also healthier soil for the next growing season.

Case Study: Results on Shallots in Brebes

In the 2025 growing season, shallot farmers in Brebes applied POC Formula Tuber Quality at a dosage of 4 ml/liter every 10 days from 25 DAP to 65 DAP. Results:

• Tuber weight per clump increased by 22% (average from 85 grams to 104 grams).
• Tuber diameter was more uniform (2–3 cm) with a hollowness rate of only 5%.
• Tuber shelf life reached 3 months without special storage, 1 month longer than usual. This case proves that biofertilizer for tubers can deliver tangible results when applied correctly.

Conclusion

The tuberization phase is a crucial moment that determines the success of tuber crop harvests. Using biofertilizer for tubers like POC Formula Tuber Quality from Biosolution offers a natural and effective solution to stimulate uniform tuber formation, increase yield weight by 15–25%, and extend shelf life. The key lies in proper application: dosage of 3–5 ml/liter, frequency every 7–10 days, and morning timing. By adopting PGPR technology, seaweed extract, and humic acids, farmers can achieve larger, denser, and high-value tuber harvests.

For further consultation on applying POC Formula Tuber Quality on your land, contact the Biosolution team via WhatsApp. Get specific dosage recommendations according to your variety and soil conditions.

FAQ

1. What is the difference between POC Formula Tuber Quality and regular POC?

POC Formula Tuber Quality is specifically formulated with a consortium of PGPR, seaweed extract, and humic acids that work synergistically during the tuberization phase. Regular POC usually only contains macro and micronutrients without hormone-inducing microbes, so its effect is not specific for tuber formation.

2. Can POC Formula Tuber Quality be used for all types of tubers?

Yes, this product is effective for potatoes, sweet potatoes, cassava, shallots, garlic, carrots, and other tuber crops. Dosage and frequency can be adjusted to the specific needs of the plant and its growth stage.

3. Is it safe to mix with pesticides or fungicides?

It is best not to mix directly with chemical pesticides because they can kill PGPR. If pesticide application is necessary, allow a minimum of 2 days before or after applying POC Formula Tuber Quality. Organic pesticides are generally safe to mix.

4. What is the minimum number of applications to see results?

A minimum of 3 consecutive applications at 7–10 day intervals already shows a noticeable difference in tuber size. For optimal results, apply 4–6 times during the tuberization phase.

5. Is this product registered with the Ministry of Agriculture?

Yes, POC Formula Tuber Quality has obtained a distribution permit from the Ministry of Agriculture and meets national liquid organic fertilizer standards. This product is also safe for certified organic farming programs.