Bio stimulants help crops use nutrients better and cope with stress such as heat, dry spells or transplanting shock. They do not replace fertilizers — they help the crop get more out of the nutrition it already receives. Choosing the right one depends on what problem you are trying to solve.
Seaweed extract
Seaweed extracts contain naturally occurring plant growth substances, minerals and carbohydrates. They are commonly used as foliar sprays during active vegetative growth and before flowering to support growth and stress tolerance. Example: Sea Amino (Seaweed Extract 10% + Amino Acids 10%) — label dose: foliar 1-2 ml per litre of water, or 1-2 litre per acre as soil application.
Humic acid
Humic acid works mainly in the soil. It improves soil structure and helps hold nutrients near the root zone, supporting root development and nutrient availability. It is typically applied to the soil at sowing or with irrigation. Examples: Humi Granules (Humic Acid 51%, granular) — 5-10 kg per acre mixed with soil; Humi Gold (Humic Acid 6% liquid) — 1-2 litre per acre soil application or 2-3 ml per litre as foliar spray.
Amino acids
Amino acids are building blocks the plant can use directly, which makes them useful at critical growth stages and for recovery after stress. Example: Amino Strong (Amino Acid 50% powder) — foliar 1-2 g per litre of water, or 250-500 g per acre as soil application.
Fulvic acid
Fulvic acid is a smaller, highly soluble humic substance that is well suited to foliar sprays and fertigation, where it helps move nutrients into the plant. Example: Fulvo Boost (Fulvic Acid 10% + Amino Acids 5%) — foliar 1-2 ml per litre of water, or 1-2 litre per acre soil application.
A simple way to decide
Weak roots or tired, compacted soil: start with humic acid in the soil. Crop under heat or dry-spell stress, or recovering after transplanting: amino acids or seaweed as a foliar spray. Before and during flowering: seaweed extract. With drip or foliar nutrition programmes: fulvic acid.
Always follow the directions on the product label and consult a local agronomist for crop-specific timing.
Frequently asked questions
Can bio stimulants replace fertilizers?
No. Bio stimulants help the crop use nutrients more efficiently and handle stress, but the crop still needs balanced fertilizer nutrition.
What is the difference between humic acid and fulvic acid?
Both are humic substances. Humic acid is larger and works mainly in the soil around the roots; fulvic acid is smaller and more soluble, which makes it suited to foliar sprays and fertigation.