Plant care calculator

Plant Fertilizer Calculator

By Bougainvillea Editorial Team ·

Analyze your fertilizer NPK ratio to ensure it promotes Bougainvillea blooms rather than just green leaves.

Quick Answer

If your fertilizer has a higher first number (Nitrogen) than the middle number (Phosphorus), it is wrong for a blooming Bougainvillea. The ideal ratio is 1:2:2 or 1:2:1 (e.g., 5-10-10).

Enter your details

Enter the labeled values below. Results appear without leaving this page.

Optional. Enter in °C for Metric or °F for US Standard. If blank, the season selection is used.

Recommended Output

Method

Dose = reference label dose x pot-volume factor x plant nutrient demand x growth-stage modifier x health safety modifier x temperature modifier x selected strength.

Reference Table

Static Bougainvillea NPK Fertilizer Calculator Reference

Visible baseline values

These baseline ratios and decision rules are included directly in the page so visitors can review core guidance before using the interactive calculator.

Scenario Baseline Rule Safety Note
Foliage plant baseline Reference label dose x pot-volume factor x plant demand x stage x health x temperature x selected strength. Apply to moist soil and avoid feeding stressed or recovering plants.
Succulent baseline Use a very dilute balanced feed; demand multiplier is low compared with foliage and flowering plants. Overfeeding succulents is a common cause of weak growth and root stress.
Dormant or recovering plant Recommended output is pause feeding / do not fertilize. Correct light, drainage, pests, or root stress before adding fertilizer salts.

Formula summary: Dose = reference label dose x pot-volume factor x plant nutrient demand x growth-stage modifier x health safety modifier x temperature modifier x selected strength.

The Problem

Many plant owners guess at their care routines, leading to root rot, burned leaves, or stunted growth. Generic advice doesn't factor in specific plant species and local climate.

When to Use This Tool

Use this calculator when you bring home a new plant, when seasons change, or if your plant is showing signs of distress.

Who is this for?

  • Beginner Bougainvillea owners looking to avoid common mistakes
  • Advanced collectors wanting to optimize growth rates

Stop feeding your Bougainvillea the wrong nutrients.

Why NPK Matters

The three numbers on your fertilizer bag represent Nitrogen (N), Phosphorus (P), and Potassium (K). For Bougainvillea, Phosphorus is the most critical element for developing those vibrant, papery bracts (flowers). Potassium ensures strong stems and drought resistance.

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Next Best Actions

Use the result in a real care workflow with plant profiles, guides, and personalized quizzes.

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Bougainvillea 'Barbara Karst' is a vigorous, popular cultivar prized for its brilliant magenta-red bracts and prolific, nearly year-round blooming habit. One of the hardiest bougainvilleas, it thrives in hot, full-sun gardens, on fences and trellises, and in large containers across tropical and subtropical climates.

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Chilli Red

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Duck Feet

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Troubleshooting Guide

1 Plant produces massive green vines but no flowers

Cause: Fertilizer contains too much nitrogen relative to phosphorus.

Switch to a high-phosphorus bloom booster (e.g., 5-10-10) and withhold water slightly to induce flowering.

Glossary of Terms

NPK Ratio
The percentage of Nitrogen (N), Phosphorus (P), and Potassium (K) in the fertilizer.
Bloom Booster
A fertilizer formulated with high Phosphorus to promote flower development.

Scientific References

  1. Plant Nutrition and Fertilizers — FAO
  2. Understanding Plant Nutrients — NC State Extension

Frequently Asked Questions

What NPK ratio is best for Bougainvillea flowering?
Look for a ratio where the middle number (Phosphorus) is equal to or higher than the first number (Nitrogen). Good options include 5-10-10 or 5-10-5. Avoid 20-20-20 or any formula where N is the dominant element during the blooming phase.
Can I use a tomato fertilizer on Bougainvillea?
Yes — tomato fertilizers are typically high in Phosphorus and Potassium, which makes them surprisingly well-suited for triggering Bougainvillea blooms. Check the label and confirm the middle and third numbers are higher than the first.