Excalibur IX vs VI vs Boost: Choosing the Right Formula for Your Plumeria

The Excalibur fertilizer line includes three specialized blends developed for plumeria: IX, VI, and Boost. While each contains a similar base of balanced nutrients and chelated micronutrients, their release duration and timing make them ideal for different climates, pot sizes, and growth phases.

This article compares the three Excalibur formulas and provides customized suggestions tailored to season length, growth stage, and performance goals.

Overview of the Excalibur Line

• Excalibur IX (11‑11‑13):
  A long-season fertilizer designed to release nutrients gradually over 9 months. Best for warm climates and uninterrupted growing cycles.
• Excalibur VI (11‑11‑14):
  A 6-month version with slightly more potassium, ideal for:
  • Shorter growing seasons
  • Cooler climate zones
  • Mid-season refeeding if plants show strong active growth
• Excalibur Boost (10‑12‑14):
  A short-duration, faster-acting blend formulated for:
  • Pre-bloom feeding
  • Transplant recovery
  • Pruned or grafted trees needing a short-term nutrient lift

All Excalibur products utilize a moisture-activated, osmosis-based release system, which is tested under conditions that mimic real-world growing environments—85°F and seasonal Florida-style rainfall. This ensures release timing matches the demands of plumeria in containers or tropical zones.

📊 Nutrient and Use Comparison

When to Use Each Formula

✅ Excalibur IX (Long Season)

• Apply in early spring as your primary seasonal feed
• Ideal for growers in Zones 9–11 or regions with long growing periods
• Works well in large containers or in-ground plantings

✅ Excalibur VI (Flexible Mid-Range)

• Choose VI if:
  • You live in a shorter-season zone (e.g., Zone 8 or cooler Zone 9)
  • Your season runs only 4–6 months before dormancy
  • You need a mid-season refresh after heavy rain, fast vegetative growth, or post-bloom recovery
• Also great for smaller containers or plants with sensitive roots

✅ Excalibur Boost (Targeted Supplement)

• Use Boost when:
  • Buds are forming and you want to push flower development
  • A newly rooted cutting or graft needs extra energy
  • You’re recovering from heat/drought stress or transplanting
• Boost can be reapplied every 6–10 weeks in high-demand periods

Application Recommendations

Apply around the root zone—not directly against the trunk—and water in thoroughly.

Combining Formulas Across the Season

You can layer Excalibur products for full-cycle success:

1. Start with IX in spring (or VI in shorter zones)
2. Add Boost during bloom spike or recovery period
3. Reapply VI mid-season only if heavy rains or aggressive growth call for it

Avoid overlapping VI and IX simultaneously. Space applications by 4–6 weeks and reduce dosage when supplementing.

Regional and Seasonal Strategy

✅ Final Takeaway

Whether you grow in-ground, in containers, or across different climates, the Excalibur trio provides precision and flexibility, feeding your plumeria exactly when and how it needs it.