Foliar Boron Spray Calculator
Mix borax / solubor to the right strength (0.2% w/v) for any tank or knapsack volume, with the per-15 L dose worked out for you.
A 0.2% boron spray (2 g/L) at flowering/fruit set corrects boron deficiency in sunflower, oilseeds and fruit crops. Dissolve borax in warm water first. Stay at or below 0.2% — boron toxicity is easy to cause.
Always follow the product label — the label is the law. Verify doses, PHI and compatibility with the manufacturer and local regulations before spraying.
Spray operators use the free Foliar Boron Spray Calculator to mix exactly the right amount of borax / solubor into any tank or knapsack — no over- or under-dosing, no leaf burn from guesswork.
About Foliar Boron Spray Calculator
Boron drives pollination and fruit set, and a 0.2% foliar spray (2 g per litre) at flowering rescues sunflower, oilseed and fruit crops showing empty centres or poor set. Boron's safe range is narrow, so precise mixing matters. This tool converts the 0.2% strength into grams of borax for your spray volume.
How to use Foliar Boron Spray Calculator
- 1Enter the concentration (default is the recommended value) and your water volume.
- 2Read the grams of borax / solubor to add, plus the per-knapsack dose.
- 3Mix in clean water, agitate, and spray in the cool of the day.
Why use Foliar Boron Spray Calculator?
- ✓Converts the recommended 0.2% concentration into grams for your exact volume
- ✓Gives the per-15 L knapsack dose automatically
- ✓Estimates the area one tank covers
- ✓Free, instant and fully in-browser — works offline in the field
Frequently asked questions
How do I mix a 0.2% borax / solubor spray?+
A 0.2% w/v spray means 2.0 g per litre of water, so a 15 L knapsack needs 30 g. The calculator scales this to whatever tank size you enter.
When should I spray for the best result?+
A 0.2% boron spray (2 g/L) at flowering/fruit set corrects boron deficiency in sunflower, oilseeds and fruit crops. Dissolve borax in warm water first. Stay at or below 0.2% — boron toxicity is easy to cause.
Can I increase the concentration to work faster?+
No — going above the recommended 0.2% risks scorching the leaves and wasting product. Repeat sprays at the correct strength instead of one strong one.
Is the tool free and private?+
Yes — free, no sign-up, and it runs entirely in your browser, so it works offline in the field.
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