Why a pesticide spray will not fix a nutrient problem
Many farmers spray pesticide when a crop looks weak, even with no pest. Why that rarely helps a nutrient problem, what it costs and what to check.
Read the full guideMicronutrients for fruit size, quality, brix and market price
How boron, calcium, magnesium, zinc and potassium decide fruit set, size, sweetness, firmness and shelf life, and so the price a grower gets.
Market price depends on size, colour, sweetness, firmness and freedom from cracks and spots, and micronutrients shape every one of these. Boron and zinc decide how many flowers set fruit, calcium and boron decide firmness and cracking, and magnesium and potassium move sugars into the fruit for brix and colour. A short supply of any of them shows up as lower grades at the market.
By Gafar Laiya and the Gujarat Bio Organics team. Updated November 2026.
What each nutrient adds
| Quality trait | Nutrients most involved |
|---|---|
| Fruit set and number | Boron, zinc |
| Size | Zinc, boron, potassium, magnesium |
| Sweetness (brix) and colour | Magnesium, potassium, boron |
| Firmness, cracking, shelf life | Calcium, boron |
| Freedom from spots and disorders | Calcium, boron, balanced nitrogen |
Crops where it matters most
- Mango: fruit set, cracking, internal disorders and shelf life.
- Pomegranate: cracking and colour.
- Grapes: uneven berries and sweetness.
- Banana: bunch size and finger fill.
- Citrus: fruit drop, size and juice quality.
- Tomato and chilli: blossom-end rot and firmness.
- Sugarcane: sugar recovery.
Practices that help
- Test the soil and leaves before flowering.
- Correct boron and zinc before flowering.
- Keep watering steady from fruit set to harvest.
- Balance potash with magnesium and calcium.
- Avoid heavy nitrogen late in fruit growth, which softens fruit.
- See our crop guides and Immunity Specials for crop programmes.
Doses depend on the crop, soil and product, so this page gives methods, not amounts. Take the dose from your soil test report, the product label or your local agriculture officer or KVK. Results differ from farm to farm with soil, weather, crop and management. Farmer experiences on this site are their own reports, not a promise of results.
Read next
Why more urea or water-soluble fertilizer does not fix yellow leaves
Yellow leaves are often treated with more urea or NPK. Why that fails when sulphur, magnesium, iron or zinc is the real cause, and what to do instead.
Read the full guideMicronutrients, soil health and sustainable farming
Why micronutrient shortage is a soil health problem, and how organic matter, residues, rotation and balanced feeding protect soil for the next generation.
Read the full guideHow Gujarat Bio Organics can help
Since 2006, lakhs of farmers from Kashmir to Kanyakumari have used Immunity products on almost every crop: from the mango farms around Somnath to the apple orchards of Himachal Pradesh and Kashmir, the tea estates of Assam and Darjeeling, and the banana, coconut and cardamom farms of Tamil Nadu, Karnataka and Kerala. Each Special is one formula made for one crop and its common problems. Tell us your crop, soil test and what you see, and our team will tell you what to check, whether a micronutrient correction is needed, and which Special fits your programme.
- Mango guide and Immunity Mango Special
- Sugarcane guide and Immunity Sugarcane Special
- Potato guide and Immunity Potato Special
- Cotton guide and Immunity Cotton Special
Results differ from farm to farm with soil, weather, crop and management. Farmer experiences on this site are their own reports, not a promise of results.
Questions
Which nutrient increases fruit sweetness?
Sugars are made in the leaves and moved into fruit with the help of magnesium, potassium and boron. A shortage of these lowers brix.
What causes fruit cracking?
Irregular watering combined with boron or calcium shortage is a common cause, especially in pomegranate, mango and tomato.