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Old Cobblers Farm™ Wicked Growth Annual Flowers Fertilizer
High-phosphorus 15-30-15 fertilizer for flowering annuals. Application rates, best flowers, and seasonal tips from Old Cobblers Farm.
Old Cobblers Farm™ Wicked Growth Annual Flowers Fertilizer
Old Cobblers Farm™ Annual Flowers Fertilizer is a high-phosphorus commercial fertilizer with a 15-30-15 NPK ratio. The 30% phosphorus content — the highest in the Wicked Growth lineup — is specifically calibrated for flowering annuals that complete their entire lifecycle in a single season and need maximum bloom energy.
Gardeners choose this formula because annuals have a limited window to flower and set seed. High phosphorus drives prolific blooming and strong root establishment, while balanced nitrogen and potassium support healthy foliage and plant resilience throughout the growing season.
NPK
15-30-15
Type
Non-Organic
Derived From
Urea, Monoammonium Phosphate (MAP), Muriate of Potash (MOP), Pelletized Lime
Best For
Petunias|Marigolds|Impatiens|Zinnias|Geraniums|Begonias|Cosmos|Snapdragons|Alyssum|Nasturtiums|Calendula|Lobelia|Torenia|Sweet Peas|Cleome|Dianthus|Verbena|Annual Phlox|Morning Glory|Calibrachoa
Brand
Wicked Growth
NPK Breakdown
N
15
15% Nitrogen promotes strong green growth
P
30
30% Phosphorus supports root development and prolific flowering
K
15
15% Potassium enhances plant resilience, stem strength, and bloom longevity
What Is It ?
Old Cobblers Farm™ Ground Flower Fertilizer for Flowering Annuals features a powerful 15-30-15 NPK ratio, designed to deliver maximum flower production and deep root development. With high phosphorus content (30%), this fertilizer is ideal for flowering annuals that need a boost during active growing and blooming phases. The fast-acting formula supercharges blooming for annuals in garden beds, borders, and containers, supporting continuous flower production from planting through frost. Whether you're growing petunias, marigolds, zinnias, or any of the dozens of annual varieties that bloom hard and fast all season, this high-phosphorus blend provides the floral energy your plants need.
When To Apply ?
For garden beds, use 1 tablespoon per square foot of garden space. For container plants, use 1 teaspoon per 6-inch pot and adjust proportionally for larger containers. Apply at planting or when new growth begins in early spring, then reapply every 4-6 weeks during growing season. Avoid late-season feeding to help plants harden off before dormancy.
How to Apply ?
1.
Pre-Moisten Soil
Water soil lightly if dry before applying fertilizer to avoid fertilizer burn on tender annual roots.
2.
Measure
Measure fertilizer using recommended quantities for your bed size or number of plants.
3.
Apply
Evenly apply to the soil surface around plant bases, keeping granules off stems and foliage.
4.
Incorporate
Gently rake into the top 1–2 inches of soil to improve contact and reduce runoff.
5.
Water In
Water thoroughly with a watering can or hose spray nozzle to activate nutrients and move them to roots.
6.
7
Apply
Evenly apply to the soil surface around plant bases, keeping granules off stems and foliage.
How To Store
Store in a cool, dry place away from children and pets. Wear gloves if preferred during application. Keep away from water sources to prevent nutrient runoff.
FAQs
1.
What is the best fertilizer for annual flowers?
The best fertilizer for annual flowers is a high-phosphorus formula like 15-30-15 that powers prolific blooming and strong root establishment. Annuals have a single season to grow, bloom, and set seed, so they need intense nutritional support — especially phosphorus — to maximize flower production. The 30% phosphorus drives explosive bloom counts, while nitrogen (15%) supports lush foliage and potassium (15%) enhances bloom color and longevity. Old Cobblers Farm™ Wicked Growth Annual Flowers Fertilizer 15-30-15 is specifically designed to help petunias, marigolds, zinnias, impatiens, geraniums, and other annuals produce their best displays all season long.
2.
How often should I fertilize annual flowers?
Fertilize annual flowers at planting time and reapply every 4–6 weeks throughout the growing season. Annuals are heavy feeders that bloom continuously and deplete soil nutrients quickly. Container-grown annuals may need even more frequent feeding — every 2–3 weeks — because nutrients leach rapidly from pots with regular watering. Stop fertilizing in late summer as plants naturally wind down. Consistent feeding is the single biggest factor in keeping annuals blooming from spring through fall. Old Cobblers Farm™ Wicked Growth Annual Flowers Fertilizer 15-30-15 delivers fast-acting, bloom-boosting nutrition with every application.
3.
What fertilizer makes zinnias bloom more?
Zinnias bloom most prolifically with a high-phosphorus fertilizer like 15-30-15. Phosphorus is the nutrient most directly responsible for flower bud formation and bloom production. Apply at planting and reapply every 4–6 weeks during the growing season. Deadheading spent blooms also encourages zinnias to produce more flowers. Avoid excessive nitrogen, which promotes tall, leafy stems with fewer blooms. A balanced approach with bloom-boosting phosphorus produces the most colorful, abundant zinnia displays. Old Cobblers Farm™ Wicked Growth Annual Flowers Fertilizer 15-30-15 supercharges zinnia bloom production for vibrant, cutting-garden-quality flowers.
4.
Is 15-30-15 good for petunias and geraniums?
Yes, 15-30-15 is ideal for petunias, geraniums, and other flowering annuals that bloom continuously throughout the season. The high phosphorus content (30%) directly fuels flower production, while nitrogen supports lush green foliage and potassium improves bloom longevity and plant resilience. Petunias and geraniums are especially heavy feeders that respond dramatically to regular phosphorus supplementation — you will see noticeably more blooms with richer color. Old Cobblers Farm™ Wicked Growth Annual Flowers Fertilizer 15-30-15 is formulated specifically for flowering annuals including petunias, geraniums, impatiens, marigolds, and calibrachoa.
5.
What is a high phosphorus fertilizer for flowers?
A high phosphorus fertilizer for flowers has a middle NPK number significantly higher than the other two — like 15-30-15, 10-20-10, or 5-10-5. Phosphorus is the nutrient most directly responsible for root development and flower production. It fuels the energy transfer processes within the plant that drive bud formation, bloom opening, and seed production. For annuals that need to bloom fast and hard, a formula like 15-30-15 delivers maximum bloom-boosting phosphorus. Old Cobblers Farm™ Wicked Growth Annual Flowers Fertilizer 15-30-15 is one of the most concentrated bloom-boosting fertilizers available for flowering annuals.
6.
Can I use 15-30-15 on hanging baskets?
Yes, 15-30-15 works well on hanging baskets filled with flowering annuals like petunias, calibrachoa, verbena, lobelia, and fuchsias. Because hanging baskets dry out and leach nutrients quickly, they benefit from the concentrated phosphorus that drives continuous blooming in limited soil volumes. Apply at planting by mixing into the soil, and reapply every 2–4 weeks during the growing season. Use slightly lower rates for small containers to avoid salt buildup. Old Cobblers Farm™ Wicked Growth Annual Flowers Fertilizer 15-30-15 keeps hanging basket annuals blooming vigorously from spring through first frost.
7
What NPK ratio is best for flower beds?
For annual flower beds, a high-phosphorus ratio like 15-30-15 maximizes bloom production. For perennial flower beds, a balanced 10-10-10 provides steady, all-purpose nutrition year after year. For bulb beds, a formula like 5-10-10 supports root establishment and spring flowering. The best ratio depends on what you are growing and what stage the plants are in. Phosphorus is always the most critical nutrient for flowering. Old Cobblers Farm™ offers specialized formulas for annuals (15-30-15), perennials (10-10-10), and bulbs (5-10-10) to match the specific needs of every flower garden.