At Todd's Nursery in Puyallup, we've seen these mistakes lead to yellowing leaves, burned roots, weak growth, or even environmental issues like runoff into local waterways. The good news? Most are easy to fix.
Building on our guides to what NPK numbers mean, how to fertilize step-by-step, and when to fertilize in the PNW, here are the top mistakes we see — and exactly how to avoid them.
1Over-Fertilizing (The #1 Killer)
Too much fertilizer is "more is better" thinking gone wrong. Excess nutrients burn roots (looks like scorched leaf tips/edges), cause leggy growth with few flowers/fruits, disrupt soil microbes, and lead to runoff — a big concern in rainy western Washington.
✅ How to avoid it:
- • Follow bag rates (or WSU guidelines: max 2–4 lbs actual N per 1,000 sq ft/year for lawns)
- • Start low — especially in clay-heavy Puyallup soils that hold nutrients longer
- • Use slow-release formulas to feed gradually
- • A soil test can confirm if you even need fertilizer
2Fertilizing at the Wrong Time
Applying too early (late winter/early spring) pushes tender growth vulnerable to frost. Late summer high-N feeds create weak shoots that freeze. Skipping fall misses the best root-building window.
✅ How to avoid it:
- • Follow our PNW timing guide: Fall (Sept–Nov) for roots, early spring (April–May) for green-up
- • Avoid mid-summer unless deficiency is clear (heat stresses plants)
- • For trees/shrubs: Stop by mid-summer to prevent frost-sensitive new growth
3Guessing Instead of Testing
Guessing leads to imbalances — adding phosphorus when your soil already has plenty (common in PNW landscapes) wastes money and risks water quality issues.
✅ How to avoid it:
- • Test every 2–3 years if you want to be precise (pH, NPK, micronutrients)
- • In Puyallup/Bonney Lake areas, many soils are low in P/K but acidic — a test reveals exactly what to add
- • Skip P-heavy fertilizers for trees/shrubs unless test shows need
- • That said, most gardeners do fine with a balanced all-purpose fertilizer
4Applying on Dry Soil or Not Watering In
Dry soil + fertilizer = concentrated salts that burn roots. Skipping post-application water leaves nutrients on top (wastes them or runs off in rain).
✅ How to avoid it:
- • Apply to moist (not soggy) soil
- • Water lightly right after (or time with rain) to move nutrients down
- • In our wet climate, natural rainfall often helps — but don't rely on it during dry spells
5Using the Wrong Type or Ratio
High-N on blooming plants = lots of leaves, no flowers. Wrong formula for acid-lovers (rhododendrons/azaleas) causes yellowing.
✅ How to avoid it:
- • Match to plant needs (see our NPK guide)
- • High-N for lawns, balanced/low-P for trees/shrubs
- • Choose slow-release/organic for PNW to reduce leaching
- • Ask at Todd's — we recommend products suited to local clay soils
6Fertilizing New Transplants Too Soon
Fresh transplants have damaged roots — fertilizer stresses them more.
✅ How to avoid it:
- • Wait 1 year for trees/shrubs (focus on watering and mulch first)
- • Use starter/low-P fertilizer for new plantings if needed
7Ignoring Runoff and Environmental Impact
Excess P/N from over-application runs into streams and lakes, causing algae blooms — regulated in Washington (e.g., no P in turf fertilizers without soil test).
✅ How to avoid it:
- • Sweep up spills on pavement
- • Use only what's needed; apply away from water sources
- • Opt for organic/slow-release to minimize runoff issues
Quick Fixes for Fertilizer Problems
My leaves look burned — what now?▼
Is under-fertilizing a problem too?▼
Can I fix salt buildup from synthetics?▼
Fertilize Smarter This Season
Avoid these pitfalls, and your yard will reward you with healthier plants and fewer headaches. Need help picking the right product or fixing an existing issue? Stop by Todd's Nursery in Puyallup — our team knows South Sound conditions inside out.
Questions? Give us a call at (253) 841-3280 — we're happy to help Puyallup, Orting, Sumner, and Bonney Lake gardeners! 🌱
— The Team at Todd's Nursery & Landscaping