Late Summer Fertilizer Tips for Healthy Fall Transitions

As August rolls in, plants are nearing the end of their summer growth cycle—but that doesn’t mean your fertilizing duties are over. In fact, late summer is one of the most important times to apply the right nutrients. Proper late-season feeding helps lawns recover from heat, encourages long-lasting blooms, and sets up trees and perennials for a smooth transition into fall.

In this blog, we’ll explore what makes late summer fertilization unique, which fertilizers are most effective, and how to apply them to maximize results without overstimulating soft, vulnerable growth. With the right approach and premium products from Supply Solutions LLC, you can finish the season strong.

Why Fertilize in Late Summer?

Many gardeners assume fertilization should taper off by mid-summer, but late-season applications offer key benefits:

• Lawns need nutrients to recover from foot traffic, heat stress, and drought.
• Vegetables are in peak production mode and require consistent feeding.
• Perennials and trees begin storing energy for winter dormancy.
• Late-planted crops like kale, spinach, or broccoli need a nutrient boost to get established quickly.

The right late-summer fertilizer strengthens plants without encouraging excessive leafy growth.

The Best Fertilizers for Late Summer

1. 10-10-10 with Micronutrients

• Provides a balanced NPK for lawns, ornamentals, and edibles
• Micronutrients promote strong color, disease resistance, and flavor
• Suitable for both in-ground and container plants

2. 12-6-6 Ornamental Blend

• Focuses on steady vegetative growth for shrubs and foliage plants
• Ideal for evergreens preparing for cooler months

3. 15.5-0-0 Calcium Nitrate

• Supports fruiting crops like tomatoes, peppers, and eggplants
• Prevents blossom end rot and aids in strong skin development

What to Avoid in Late Summer Fertilization

• Excessive nitrogen on trees and perennials: Encourages soft growth that won’t harden before frost.
• Heavy feeding of already stressed plants: Focus on recovery first with water and mulch.
• Fertilizing during drought: Always water well before and after application.

Lawn Fertilization Tips for August

If your lawn has thinned, yellowed, or suffered heat stress, now is the time to apply a slow-release fertilizer to aid recovery.

• Use Ammonium Sulfate (21-0-0-24S) to improve greening while also lowering high soil pH.
• Reapply every 4–6 weeks until mid-September.
• Mow high and water deeply to minimize future stress.

Feeding Fall Crops Started in August

• Broccoli, kale, spinach: Benefit from balanced 10-10-10 applications.
• Radishes and lettuce: Light weekly feedings with diluted 10-10-10 or 12-6-6 work best.
• Late-season tomatoes and peppers: Apply calcium nitrate every 7–10 days.

Late Summer for Trees, Shrubs, and Perennials

• Use a diluted 12-6-6 feeding to help shrubs rebuild energy stores.
• Stop fertilizing trees after mid-September to allow hardening off.
• Don’t fertilize plants that are already dropping leaves.

Tips for Best Results

• Time applications for early morning or late evening.
• Water in immediately to prevent nutrient burn.
• Apply before expected rainfall for natural incorporation.
• Mulch around the base of plants to retain moisture and regulate root temperature.

Final Thoughts

Late summer fertilizing helps you wrap up the season with stronger plants, greener lawns, and a head start on fall productivity. With products like 10-10-10, 12-6-6, and calcium nitrate, you can ensure a healthy transition into the cooler months ahead.

Need help choosing the right product for your late-summer goals? Connect with the experts at Supply Solutions LLC.

Call us at 503-451-1622
Email sales@mysolutionssupply.com
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Let Supply Solutions LLC help you maximize your summer garden before fall arrives.