To Soak or Not to Soak? Your Definitive Guide to Microgreen Seed Prep

If you’ve spent any time online looking up how to grow microgreens, you’ve probably fallen down the rabbit hole of seed prep. One forum says to soak everything, a blog post says to soak nothing, and a video shows a 12-step process that seems more complicated than building a rocket.

It’s confusing. And when you’re excited to start growing, that confusion can be frustrating.

So let's cut through the noise. As growers who are passionate about getting incredible results every single time, we’ve turned this process into a science. This is your definitive, no-nonsense guide to prepping microgreen seeds. We’ll show you exactly when to soak, when to skip it, and a few pro-level techniques that will take your harvest to the next level.

Why Bother with Seed Prep? (It’s Not Just for Show)

So, why do we even bother with all this? It’s simple: you’re giving your seeds a massive head start. Proper preparation, especially soaking, dramatically increases germination rates and leads to a more uniform, healthy crop.

Think of it this way: a seed is a tiny plant in a deep sleep, wrapped in a protective coat. Your job is to wake it up. Soaking does three critical things:

1. It Softens the Armor: For larger seeds like sunflowers and peas, soaking softens their tough outer shell, making it much easier for the sprout to break free.

2. It Washes Away Inhibitors: Many seeds are protected by natural compounds that act like a 'stop sign' for germination. This is a key part of what's known as seed dormancy, a survival trait that keeps them from sprouting at the wrong time. Soaking effectively washes these inhibitors away, giving the seed the 'green light' to grow.

3. It Fires Up the Engine: Water activates the enzymes inside the seed, which start converting stored starches into the energy needed for that initial growth spurt.

By doing this, you’re not just hoping for the best; you’re setting your seeds up for success from day one.

The "Must-Soak" List: Seeds That Need a Drink

Alright, let's get to the specifics. For these larger seeds with tough hulls, soaking is a non-negotiable step for a great harvest. It’s the difference between a sparse, uneven tray and a lush, dense canopy of greens.

Once you see the incredible results from properly soaking your sunflower and pea seeds, you'll naturally start to ask, 'What else can I grow?' That's the exciting part.

While this guide gives you the crucial how-to for these popular seeds, our Ultimate Guide to Microgreens: 100 Varieties is your perfect next step. It’s your comprehensive library for discovering and mastering dozens of other delicious and nutritious microgreens, from amaranth to wheatgrass.

The "Do Not Soak" List: How to Avoid a Slimy Mess

Just as important as knowing when to soak is knowing when not to. If you’ve ever ended up with a tray of gelatinous, clumpy seeds, you’ve probably met a mucilaginous seed.

When these seeds get wet, they develop a slimy, gel-like coating. This causes them to stick together, makes even sowing a nightmare, and creates a perfect environment for mold.

For a successful, clean grow, never soak these seeds:

• Basil

• Arugula (Rocket)

• Chia

• Cress

• Flax

• Mustard (most varieties)

Additionally, most tiny seeds like broccoli, kale, and cabbage don't need a soak. While it might speed things up by a few hours, it makes them incredibly difficult to spread evenly. You’ll get much better results by sowing them dry onto your moist Vegbed mat.

Your Go-To Soaking Protocol

Ready to put it all into practice? Here is the simple, step-by-step process we use for a perfect soak every time.

1. Quick Rinse: Before anything else, give your seeds a quick rinse in a strainer with cool water to wash off any dust.

2. Sanitize (Optional but Recommended): For mold-prone seeds like sunflower and pea, perform the 5-minute sanitization step with food-grade hydrogen peroxide now, followed by another thorough rinse.

3. The Soak: Place your clean seeds in a bowl and cover them with plenty of cool, room-temperature water. A 4-8 hour soak is the sweet spot for most varieties.

4. Final Rinse: After the soak, drain the seeds and give them one last thorough rinse with cool water.

5. Plant Immediately: Your seeds are now awake and ready to grow! Don’t let them dry out. Sow them right away onto your prepared Vegbed mat for the best results.

Beyond Soaking: Two Techniques to Level Up Your Grow

Ready to move beyond the basics? These two professional techniques will help you tackle tricky seeds and ensure your harvest is as clean and healthy as possible.

1. Seed Sanitization: Start Clean, Grow Clean

You wouldn't cook in a dirty kitchen, so why start your grow with dirty seeds? Seed hulls, especially on larger seeds like sunflower, can carry invisible mold spores. A quick sanitizing step is your best defense against a moldy tray.

• How to do it: A brief, 5-minute soak in a 3% food-grade hydrogen peroxide solution is a simple and highly effective method. It’s crucial to use food-grade H2O2, as the common brown bottle has stabilizers you don’t want on your food. After the 5-minute soak, give the seeds a very thorough rinse with cool water before moving on to your main water soak or planting.

Seeds That Need Extra Attention on Sanitation

• Sunflower: Their ridged hulls can carry a high load of field contaminants, making them prone to mold without proper cleaning.

• Peas: A larger seed that often carries field dust and bacteria, which can cause issues during their long soak time.

• Cilantro: Breaking the husk during scarification can introduce pathogens, so sanitizing afterward is a key step.

• Buckwheat: The hard, angular hulls can trap contaminants, increasing the risk of mold in the dense crop.

2. Scarification: For the Extra-Tough Seeds

Ever had a seed that just refuses to sprout? It might have an extra-tough, water-impermeable coat. Scarification is simply the process of gently scratching or weakening this outer shell to let water in.

• How to do it: For home growers, mechanical scarification is the safest bet. You can gently rub larger seeds on a piece of sandpaper or a nail file—just enough to scuff up the surface without damaging the seed inside. This little bit of tough love can make all the difference for stubborn seeds like nasturtiums.

Seeds That Need Scarification

• Cilantro/Coriander: Its husk contains two seeds; gently crushing it open is essential for good germination.

• Beets & Swiss Chard: These are hard, clustered fruit pods, and abrading the tough outer shell helps water penetrate.

• Spinach: The tough, irregular coating on these seeds can block water absorption if not broken down.

• Nasturtium: Their large, wrinkled seeds have a very tough coat that needs to be scuffed to ensure proper hydration.

And that’s it! You’re now armed with the knowledge to prep your seeds like a pro. By understanding which seeds need a little extra attention, you can take the guesswork out of germination and look forward to a consistently lush, healthy, and delicious harvest.

Happy growing!