Seed Starting 201 – From Sowing Seed to Organic Fertilizer for Seedlings & Transplanting

Introduction: Why Seed Starting Matters

Starting your garden from seed is one of the most rewarding—and cost-effective—ways to grow a thriving, organic garden. It gives you greater control over plant variety, timing, and the organic practices you follow from the very beginning. But transitioning from sowing seed to healthy transplants requires attention to detail, especially when it comes to light, timing, transplanting, and choosing the best organic fertilizer for seedlings.

In this guide, we’ll walk you through everything you need to know about seed starting, from the right lighting setup to fertilizing and transplanting young plants. Along the way, we’ll answer common questions about what is sowing seeds, how to care for sprouting seeds, and which organic seedling fertilizer is best for supporting robust, resilient plants.

Watch our Seedling Care video for a full visual walkthrough of these steps and more.

What Is Sowing Seeds?

Sowing seed is the process of planting seeds either directly into the garden or into containers to begin the growing cycle. For seed starting indoors, sowing usually involves using trays, pots, or soil blocks in a controlled environment. The goal is to give seedlings the best possible start before transplanting them outdoors.

You can choose to sow into biodegradable pots, plastic seed trays, or use soil blockers for a zero-waste method. Selecting the right method depends on your available space, plant type, and gardening style.

Seedlings with adequate light are upright with straight stems.	Seedlings that don’t get enough light will be “leggy” and flop over.

Light for Seedlings: The Foundation of Strong Growth

How Much Light Do Seedlings Need?

Seedlings need 16 hours of bright light per day to develop strong, upright stems and healthy foliage. Without enough light, seedlings become "leggy," stretching out and flopping over due to weak stem development.

Depending on what you're growing, seeds may require different lighting conditions to germinate:

• Germinate in the dark: Pot marigolds, verbenas

• Light indifferent: Hollyhocks, zinnias

• Light needed: Lettuce, petunias

While a bright south-facing window might suffice for some seedlings, most gardeners benefit from using grow lights for consistent results. Adjustable-height grow lights let you raise the fixture as plants grow.

Understanding Seedling Development

The first set of leaves that emerge are cotyledons (seed leaves), which help jump-start growth. The second set are true leaves—a sign that your plant is developing normally and is ready for further care, such as transplanting and fertilization.

If your seedlings suddenly collapse at the base, you may be facing damping off, a fungal issue that kills young seedlings. Learn how to prevent it with our guide on damping off.

Transplanting Seedlings: Giving Them Room to Grow

Once your seedlings have developed their first set of true leaves, it’s time to transplant them into larger containers. Start by moving them from trays into 3–4 inch pots, which you can find in our plastic pots or biodegradable pots collections.

Transplanting Tips

• Use a widger or nitpicker like the Nitpicker tool to lift seedlings gently from trays.

• Handle seedlings by their leaves—not stems—to avoid crushing vital vascular tissues.

• Replant them in a moistened soilless mix and firm gently around the roots.

• Water immediately after transplanting to help them settle.

If you're using soil blocks, nest smaller blocks inside larger 4-inch soil blocks to give roots room to expand naturally.

Organic Fertilizer for Seedlings: Feeding for Success

When to Start Fertilizing

Once your seedlings are transplanted and true leaves are fully formed, it's time to introduce organic fertilizer for seedlings. These early stages are critical, and choosing the right organic plant food for seedlings can make all the difference in development.

Best Organic Fertilizer for Seedlings

We recommend the following high-quality, easy-to-use organic liquid fertilizers for seedlings:

• Peaceful Valley Organic Liquid Fish Fertilizer – A nitrogen-rich formula ideal for green leafy growth.

• Organic Liquid Kelp Fertilizer – Encourages root development and stress tolerance.

• Maxicrop Kelp Extract – A concentrated kelp extract that boosts germination and plant vigor.

TIP: Instead of following a set fertilizing calendar, use 1/4 of the recommended fertilizer amount every time you water. This “low and slow” method prevents nutrient burn and promotes steady growth.

These formulas are ideal fertilizer for seedlings organic in nature, providing gentle nutrition without harming delicate roots. For long-term success, look for the best organic fertilizer for seedlings that balances nitrogen, phosphorus, and potassium without synthetic additives.

Hardening Off: Preparing Seedlings for the Outdoors

Before transplanting seedlings to the garden, they need to be “hardened off”—acclimated to the outdoor environment. This prevents transplant shock and ensures they adjust to sun, wind, and temperature changes.

How to Harden Off Seedlings

• Start two weeks before transplanting.

• Move plants outdoors to a shaded area for 2–3 hours per day, gradually increasing their time in the sun.

• Avoid wind and temperatures below 45°F.

• Reduce watering slightly but don’t let the seedlings wilt.

• Alternatively, place seedlings in a cool indoor area (45°F–50°F) for gradual exposure.

Our Seedling Care video demonstrates this step-by-step hardening process.

Conclusion: Set Your Seedlings Up for Success

From sowing seed to applying organic fertilizer for seedlings, every step in the seed starting process plays a vital role in raising healthy, resilient plants. By providing proper lighting, preventing diseases, choosing the best containers, and feeding with organic seedling fertilizer, you create a strong foundation for your garden's future.

Growing from seed is both an art and a science—but with the right tools, techniques, and a little patience, you’ll be well on your way to a thriving, productive organic garden.

FAQs About Seed Starting and Seedling Care

• What is the best fertilizer for seedlings?
  • The best organic fertilizer for seedlings includes gentle, natural options like fish emulsion, kelp extract, and seaweed-based formulas. These provide a steady supply of nitrogen and micronutrients without burning delicate roots.
  • Try:

    • Organic Liquid Fish Fertilizer

    • Organic Liquid Kelp

    • Maxicrop Kelp Extract

• What is the best way to start a seed?
  • Start seeds in trays or soil blocks using sterile, moistened seed starting mix. Place them in a warm, well-lit location. Use grow lights for consistent light exposure (16 hours daily), and cover with a humidity dome until germination.
• What is seed starting formula?
  • Seed starting formula refers to a growing medium or fertilizer blend specifically designed for young seedlings. It often includes a fine-textured, low-nutrient soil and a mild organic liquid fertilizer for seedlings to encourage root development.
• What is the best way to sow a seed?
  • Place seeds at the depth specified on the seed packet, usually 1–3 times the diameter of the seed. Use a moist, well-draining seed starting mix, and cover lightly. Keep soil consistently moist but not soggy until germination.
• How do you take care of seedlings?
  • Provide 16 hours of light, consistent moisture, and gentle airflow. Watch for signs of damping off, and begin feeding with organic plant food for seedlings after true leaves develop. Transplant to larger pots as needed and harden off before outdoor planting.
• How to successfully grow seedlings?

  • Use sterile, high-quality seed starting mix

  • Provide proper light and temperature

  • Prevent damping off with airflow and hygiene

  • Transplant at the right time

  • Use fertilizer for seedlings organic to support strong early growth

• How to take care of a sprouting seed?
  • Keep the soil lightly moist, provide light if needed (depending on the seed), and avoid overwatering. Once the sprout emerges and develops cotyledons, begin monitoring for true leaves and prepare for transplanting.

🌱 Resource Area:

Integrated Pest Management (IPM)

Apply a systematic approach to prevent and manage indoor plant pests using natural methods:

• What Is Integrated Pest Management (IPM)? – Covers monitoring, prevention, and targeted treatments for pests.
• Organic House Plant Care and Pest Control – A guide to natural pest control methods for indoor plants.

Mastering the Calculator

Start by understanding how to use the Seed Planting Calculator to accurately schedule your indoor and direct sowing dates:

• Step‑by‑Step Guide to Using Our Seed Starting Calculator – Detailed guidance on using the calculator effectively.
• How to Use the Seed Starting Calculator – Shows how to calculate ideal planting dates based on frost timing and crop needs.

Transplant Shock-Free Transitions

Make planting day smooth with acclimation techniques, timing tips, and soil guidance:

• How to Transplant Your Seedlings & Small Plants – Details on timing, root preparation, and reducing transplant stress.
• Harden Off Your Seedlings – A must-read for minimizing transplant shock and prepping plants for garden life.