Skip to content
Free · Instant · In-browser

Boron Application & Borax for a Target B Rate

Feeds cauliflower

Product per haTotal productAreaTarget B

This tool gets better every time someone says what confused them.

Enter your target boron rate and area to get the borax product needed — boron has a narrow safe margin, so dose carefully and apply it evenly.

Boron application rate

Your result
19.05 kg borax
Total boron product to apply
Boron safe-dose window · kg B/ha012341● optimal 0.5–2toxic >3 ●
9.52
kg/ha
1
kg B/ha
10.5
% B
2
ha
What this means
To supply 1 kg B/ha from a 10.5% boron product you need 9.52 kg/ha. Warning: boron has a very narrow margin between deficiency and toxicity — do not over-apply, and never double up "to be safe".

Next: apply 9.52 kg/ha of product (19.05 kg total). Spread it evenly and well-diluted — never band concentrated boron near seed.

Boron is the classic narrow-margin nutrient. Even crops vary: brassicas need it, beans burn easily. Confirm with a soil test.

Boron application — key facts

Borax boron
≈ 10.5% B
Product needed
target B ÷ 0.105
Total product
product per ha × area
Safe margin
Narrow — excess is toxic
Corrects
Hollow stem, fruit cracking
Poor seed set
Cauliflower, groundnut, cotton
Apply
Evenly; bulk small doses
Privacy
Runs in your browser; nothing uploaded

A tiny nutrient with an outsized effect — and a narrow safe margin

Boron is needed in only tiny amounts, but a shortage wrecks the parts of a crop that matter most: it causes hollow stem, fruit cracking and poor seed set in crops like cauliflower, groundnut and cotton. Because boron drives cell-wall formation, flowering and pollination, a deficiency shows as deformed, corky, empty growth even when everything else is right. The fix is a measured dose of borax, which is about 10.5% boron.

This tool turns a target B rate into the borax product per hectare and total product for your area. The catch is that boron has a narrow safe margin — too much is toxic — so weigh accurately, bulk small doses with sand or soil, and spread evenly. Pair it with the Micronutrient Spray and Crop Nutrient Removal calculators to build a complete, balanced nutrition plan.

Hit the right rate

Convert target boron straight to borax.

Stay below toxic

Respect boron's narrow safe margin.

Fix deficiency signs

Stop hollow stem and fruit cracking.

Buy the right amount

Total product for your whole field.

Frequently Asked Questions

What does a boron application calculator do?+

It converts a target boron (B) rate into the amount of borax product you need to apply, for your area. You enter the B rate you want to supply and the field size, and it gives the borax per hectare and the total product to buy — so you hit the right boron dose without guesswork.

Why is boron important for crops?+

Boron corrects deficiencies that cause hollow stem, fruit cracking and poor seed set in crops like cauliflower, groundnut and cotton. It is vital for cell-wall formation, pollination, flowering and the movement of sugars, so a shortage shows up as deformed growth, cracked or corky fruit, and empty pods or heads.

How much boron does borax contain?+

Borax is roughly 10.5% boron by weight, so about 10 kg of borax supplies a little over 1 kg of actual boron. The calculator uses this content to work back from your target B rate to the borax product needed — apply more product to get more elemental boron.

Why does the dose need to be so careful?+

Boron has a narrow safe margin — the gap between enough and too much is small, and excess boron is toxic to plants, causing leaf-tip scorch and stunting. Always weigh and spread borax accurately, distribute it evenly, and never apply a heavy band near seeds or roots.

Soil application or foliar spray?+

Both work. Soil-applied borax corrects a season-long deficiency and is what this calculator sizes; a dilute foliar spray gives a quick boost at flowering. For foliar use, dissolve a small amount fully and spray in cool conditions — and still respect the narrow safe margin.

How do I know my crop is boron deficient?+

Watch for the classic signs: hollow or browned stems in cauliflower and brassicas, cracked or corky fruit and tubers, poor pod and seed fill in groundnut and pulses, and dying growing points. A soil or tissue test confirms it before you commit to a corrective dose.

How do I apply borax evenly over a small dose?+

Because the rate per hectare is small, mix the borax with dry sand, soil or another fertiliser to bulk it up, or dissolve it for spraying. Bulking spreads the tiny quantity uniformly and avoids hot spots where over-application could turn toxic.

How often should boron be applied?+

Boron does not persist long in soil, especially light, leached or high-pH soils, so it is usually applied each season for responsive crops rather than building a reserve. Re-test periodically and only repeat the corrective dose where deficiency is confirmed.

Are the figures precise?+

They are solid planning figures based on borax being about 10.5% boron. Real boron needs vary with crop, soil type, pH and leaching, so confirm with a soil or tissue test, apply evenly, and treat the result as a careful starting dose rather than an exact prescription.

Related farming tools

Explore the toolkit

1900+ free tools, zero sign-up

Calculators, developer & SEO utilities, data, content, hardware and farming — all instant, private and in your browser.

Browse all tools
Calculator

Best Focus Hours

Open
Farming

Transplanting Labour Calculator

Free transplanting labour calculator. Enter the field area, plant density and how many seedlings one worker se

Open
Dev & SEO

Webhook Documentation Generator

Define your webhook events and sample payloads, then generate complete documentation: an event catalog, an inf

Open
Niche

Remote Work Carbon Calculator

Quantify the carbon shift from in-office to remote / hybrid work with a live home-vs-office balance scale. Use

Open
Content

Robots.txt Studio

Build and test robots.txt in your browser: RFC 9309 longest-match testing with the winning line highlighted, l

Open
Hardware

CPU & GPU Tier List Pro

The hardware hierarchy measured five ways: 130+ CPUs & GPUs (2015–2025) ranked into live S–D tiers by performa

Open
Productivity

Password Strength Tester

Open
Pro

Local LLM Hardware & Model Directory

Browse every GPU, model and best-of guide in the Local AI Advisor: what each graphics card can run, hardware r

Open
Calculator

JST to IST Converter

Convert Japan Standard Time (JST, UTC+9) to India Standard Time (IST, UTC+5:30). IST is exactly 3 hours 30 min

Open
Farming

Trellis Wire Calculator

Free trellis wire calculator. Enter plot size, row spacing, post spacing and number of wire lines to get rows,

Open
Dev & SEO

npm Dependency Analysis Fundamentals

MD5, SHA-256, SHA-512, SHA-3, BLAKE2, HMAC, PBKDF2, file hashing, verify, compare & free API — all in your bro

Open
Niche

Supply-Chain Carbon Calculator

Quantify Scope 3 Category 1 (purchased goods) emissions across tier-1, tier-2 and tier-3 suppliers with a live

Open
Content

Schema Markup Studio

Generate valid JSON-LD for Article, Product, FAQ, LocalBusiness, Event, Recipe, BreadcrumbList, JobPosting and

Open
Hardware

Silicon Architecture Explorer

Explore CPU and GPU silicon: group every part by microarchitecture (Zen, Ada Lovelace, RDNA, Ampere, Blackwell

Open
Productivity

Password Tools

Test password strength against real standards (NIST 800-63B, OWASP ASVS), check against known breaches via k-a

Open
Pro

Vigyan Bhairav Tantra

Open
Calculator

Palindrome Date Finder

Open
Farming

Triangular Planting Density Calculator

Free triangular (hexagonal) planting density calculator. Offsetting every other row into a triangular pattern

Open
Dev & SEO

Is Your JavaScript Bundle Too Big?

Drop a JS/CSS bundle or paste a webpack/Next.js stats.json and get the real gzip and Brotli size, an interacti

Open
Niche

Compliance Cost Estimators

Project full GDPR compliance cost — DPO staffing, DPIA, vendor audits, breach response, fines exposure

Open
Content

Security Headers Grader

Grade your HTTP response headers against the OWASP baseline: HSTS, Content-Security-Policy, X-Content-Type-Opt

Open
Hardware

CPU GPU Compare Pro

Compare any two CPUs or GPUs side by side: metric-by-metric table with the winner highlighted, the performance

Open
Pro

All 112 Techniques (Dharanas)

Browse the meditation techniques (dharanas) of the Vigyan Bhairav Tantra by method — breath, sound, void, ligh

Open
Calculator

Life Calendar

See your entire life as a grid of 4,680 weeks. Enter your birthday to discover how many weeks you've lived, tr

Open