Understanding Seed Dormancy & Germination Rates for Challenging Microgreen Varieties

Microgreens are known for their rapid growth cycle and consistent yields, but not every variety behaves in the same manner. Some seeds, such as cilantro and parsley, have built-in dormancy mechanisms that can slow down germination.

These challenging varieties require specific techniques, including pre-soaking and scarifying, as well as proper blackout periods and moisture management.

In this guide, we will explore what seed dormancy is, why some microgreens are slow to sprout, and the proven methods to achieve uniform germination. We will also highlight practical examples of pre-soak times, scarification techniques, and moisture control that work for both hobby growers and commercial farms.

What is Seed Dormancy?

Seed dormancy is a natural survival mechanism that prevents seeds from sprouting until conditions are optimal. In the wild, this helps plants avoid unfavorable seasons like winter or drought. For microgreen growers, however, dormancy can be frustrating because it delays growth and leads to uneven trays.

Cilantro (coriander) and parsley are prime examples. Without intervention, they can take over 10 days to germinate, while other microgreens like radish or broccoli can sprout in just 2–3 days. To overcome this, growers use methods such as soaking, scarifying, or temperature manipulation.

Common Causes of Poor Germination

Even for easy microgreens, germination can fail if conditions are off. Here are the main factors that affect challenging seeds:

• Hard seed coats: Seeds like cilantro and beet have tough outer shells that slow water absorption.
  

• Temperature sensitivity: Some herbs prefer warm germination zones (65–75°F).
  

• Moisture inconsistency: Too much or too little water can prevent seeds from activating.
  

• Lack of pre-treatment: Many slow-germinating seeds benefit from soaking or light scarification.
  
  

Proven Methods to Improve Germination

1. Pre-Soaking Seeds

Pre-soaking helps soften the outer shell, allowing water to penetrate the seed faster.

• Cilantro: Soak for 12–24 hours in room-temperature water. Many growers even “split” coriander seeds by gently pressing them to expose the inner seed.
  

• Parsley: Soak for 8–12 hours to break natural dormancy.
  

• Beet & Swiss Chard: A 6–8 hour soak shortens germination time and improves consistency.

2. Scarification

Scarification involves scratching or nicking the outer coat to allow water in.

• Parsley: Rub gently between fine-grit sandpaper or a kitchen towel before soaking.
  

• Cilantro: Lightly press or roll the seeds to crack their hulls before soaking.
  
  

3. Proper Blackout Period

Challenging microgreens often require a longer blackout stage (4–6 days) compared to quick crops like radish (2–3 days). Cilantro and parsley, for example, need this extended dark period to establish strong roots.

4. Consistent Moisture

Uneven moisture is one of the biggest mistakes growers make. The surface of your mat or soil should be evenly damp—not dripping wet or too dry. Check out our Essential Guide to Watering Microgreens for a detailed look at the best watering systems.

5. Optimal Lighting After Germination

Once the seeds have germinated, transition them to 12–16 hours of light daily. Learn how to fine-tune your lighting setup with our Comprehensive Guide to LED Lighting for Microgreens.

Top Challenging Microgreen Varieties and Their Requirements

Here are the microgreens that often require pre-treatment and special care:

• Cilantro (Coriander): Pre-soak and split seeds. Germination time: 8–14 days.
  

• Parsley: Scarify and soak overnight. Germination time: 10–16 days.
  

• Beet: Pre-soak for 8 hours. Germination time: 6–10 days.
  

• Swiss Chard: Pre-soak 8 hours. Germination time: 6–10 days.
  

• Sunflower: Requires a 6–12 hour soak and proper weight during blackout.
  

For a complete reference on all varieties, see our 100 Microgreens Varieties Guide.

Practical Example: Cilantro vs. Radish Germination

To understand the difference, consider this scenario:

• Radish: With no pre-treatment, radish germinates in 48 hours and is ready to harvest in 7 days.
  

• Cilantro: Without soaking or scarification, cilantro may take 14 days to germinate and up to 28 days to harvest.
  

This is why growers often charge more for cilantro microgreens—it takes longer and requires extra steps.

Top Challenging Microgreen Varieties and Their Requirements

Why Dormancy Matters in Microgreen Production

For commercial growers, time is money. If one tray takes twice as long to mature compared to another, it directly affects yield per cycle and profitability. Understanding dormancy helps growers make informed decisions about which varieties to grow for both flavor and business reasons.

Some farms avoid difficult seeds because of their slow turnaround, but with the right system, even challenging microgreens can deliver strong profits due to their premium pricing and unique appeal to chefs.

The Role of Growing Medium

Many of the challenges with difficult seeds are related to inconsistent moisture and mold risks. Traditional soil mixes can make this worse. Clean, soil-free substrates like Vegbed bamboo mats provide the right balance of air and water retention, which supports better germination and reduces contamination risk.

For varieties like cilantro and parsley, where every day of delay matters, having a consistent medium can make the difference between success and frustration.

Tips for Commercial Growers

For commercial farms, slow germination can mean higher costs due to longer tray cycles and less predictable harvests. To stay profitable:

• Track germination rates for each seed batch.
  

• Use reliable mats like Vegbed bamboo fiber mats, which provide consistent moisture and reduce mold risk.
  

• Consider pre-soaking seeds in batches to streamline operations.
  

Also, for growers who plan to sell, proper certifications are crucial. Read our Guide to Certifications for Microgreen Growers to make sure you’re market-ready.

Final Thoughts

While many microgreens are easy to grow, challenging seeds like cilantro and parsley require a bit more patience and preparation. By using methods such as pre-soaking, scarification, and controlled moisture, you can achieve healthy and uniform crops.

For a deeper dive into all microgreen types, download our Microgreen Variety Table (1–100, Sorted by Difficulty). This printable chart includes difficulty levels, seed densities, sustainability scores, and yield estimates for every crop we tested.

If you want to learn more about growing microgreens, get expert tips and stay updated with the latest news, subscribe to our newsletter.