Borax (Sodium borate, Na₂B₄O₇·10H₂O)
Type: Mineral / micronutrient fertilizer
Source: Naturally occurring borate mineral, typically mined from evaporite deposits in arid regions. Purified borax is a white crystalline powder or granular substance.
Description: Borax is an alkaline, water-soluble mineral rich in boron, a trace element essential for plant growth. It appears as colorless to white crystals with a slightly soapy texture. It is commonly used in horticulture and agriculture to correct boron deficiencies in soil, particularly in sandy or highly leached soils.
Nutrient Profile:
- Primary nutrient: Boron (B)
- Contains minor sodium content; no significant nitrogen, phosphorus, or potassium.
Uses in Gardening & Agriculture:
- Applied in very small quantities to correct boron deficiency, which is essential for cell wall formation, flowering, and fruit set.
- Beneficial for fruit trees (e.g., apples, pears, citrus), vegetables (e.g., cauliflower, cabbage), and legumes.
- Often dissolved in water for foliar application or incorporated into the soil in microgram-per-gram quantities.
Application Notes:
- Excess borax is highly toxic to plants; precise measurement is critical. Typical rates are 2–5 grams per square meter for soil amendment, depending on soil testing.
- Should be stored in a dry, airtight container to prevent caking.
- Used in combination with other fertilizers for balanced nutrition; avoid applying on very sandy soils without irrigation, as leaching can occur.
Botanical Significance:
Boron supplied by borax is crucial for reproductive development, sugar transport, and cell wall integrity. Boron deficiency manifests as poor fruit set, hollow stems, distorted growth, and necrotic leaf tips. While not a plant itself, borax plays a vital role in supporting optimal plant growth when applied correctly.