Growing Microgreens Without Soil: Comprehensive Home Growing Guide

After years of trial and error (and plenty of moldy trays!), I’ve finally perfected a foolproof system for growing microgreens without soil. This comprehensive guide walks you through every step of the soil-free growing process – from setting up your first tray to maintaining continuous harvests. Whether you’re a complete beginner or looking to refine your technique, this step-by-step method will help you grow beautiful, nutritious microgreens in your own kitchen with minimal mess and maximum results.

If you’re wondering which varieties to grow first, check out my guide to the Top 5 Microgreens for Soil-Free Growing, where I cover the best-tasting and easiest varieties for beginners.

If you’re looking for variety-specific growing guides, you’ll find detailed tutorials on the blog for different microgreens, such as my Step-by-Step Guide to Growing Broccoli Microgreens Without Soil.

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🛠️Essential Equipment

• Growing Trays: Here’s a wonderful surprise – you don’t need to buy special trays for growing microgreens!
  
  You’ll need two containers per batch: one with drainage holes for growing your microgreens and a solid bottom tray to catch water. The good news is that plastic produce containers from the grocery store work perfectly for this purpose. These containers are already food-grade (important since you’re growing food) and often come with a clear lid you can use during germination.
  
  Setting up is simple: just create drainage holes in one container using a drill or something sharp, and use a second container without holes as the bottom tray. Other good options include shallow food storage containers or any clean flat containers you already have in your home – just ensure they’re food-grade plastic.
  
  This is a perfect example of how you can grow microgreens without investing in expensive specialized equipment!

• Growing Medium: After trying several options, I settled on bamboo fiber growing mats from VEGBED. I chose them because they hold moisture well without becoming soggy, and they make harvesting much cleaner. They’re also made from biodegradable materials, which I appreciate from an environmental perspective. I get mine from VEGBED’s Official Site and have arranged a special discount for my readers with code DINASGARDEN.

• Lighting: Natural light from a window is perfectly fine for growing microgreens, and I’ve had many successful batches grown on a sunny windowsill. However, if you have limited natural light or want more consistent results year-round, a simple LED grow light can be helpful. You don’t need anything fancy – my inexpensive light (under $30) works great when positioned about 12 inches above the trays with a basic timer.
• Watering Tools: A simple spray bottle for early stages and a small watering can for bottom watering later.

Cleaning & Setup

I always start with clean trays, washing them with a simple vinegar solution between uses. This extra step might seem fussy, but it’s prevented countless mold issues – definitely worth the five minutes!

Next, I place my grow mat in the tray with drainage holes, then nest this tray inside the solid bottom tray. This two-tray system allows excess water to drain while preventing mess and enabling bottom watering later.

I thoroughly moisten the grow mat before adding seeds – either spray it well with a spray bottle or pour about half a cup of water evenly across the surface and let it absorb for a few minutes. It should be damp throughout but not dripping wet.

Seed Preparation

Now comes the seed prep, which varies by variety. My sunflower and pea seeds need an 8-12 hour soak in room temperature water before planting. It’s amazing to watch them plump up and sometimes even begin to split – that’s when you know they’re ready! The smaller seeds like radish, broccoli and mustard can skip the soaking step.

Sowing Seeds

Spreading the seeds evenly is critical – I learned this the hard way after several moldy batches caused by clumping! Different varieties need different spacing – sunflower and pea shoots generally need more room compared to smaller seeds like broccoli, radish, and mustard. Experiment to find what works best in your environment. After spreading the seeds, mist lightly to ensure good contact with the growing medium.

Germination Phase

For successful germination, all microgreens need complete darkness initially. Simply cover your tray with another tray or a dark lid to block all light. To create better seed-to-medium contact, place a small weight on top – I usually stack another empty tray on top and put something moderately heavy in it like a few books or a water bottle.

Keep your trays at room temperature (around 68-75°F) during germination. Most varieties will sprout in 2-3 days, though some like mustard might appear in just a day while pea shoots can take 3-4 days.

During this phase, check moisture daily with a quick peek under the cover. The mat should stay evenly damp but never soggy. A light mist is all that’s needed if things look dry.

If you want to see this process in more detail for a specific variety, I’ve documented the entire germination process step-by-step in my Broccoli Microgreens Growing Guide, which shows exactly how the seeds develop from day to day.

Light Exposure

The most exciting moment is when you remove the cover and reveal your sprouts reaching for light! I place them in bright indirect light – either under my LED grow light or near a bright window without direct sun (which can scorch tender seedlings). Most varieties do fine at normal room temperature (68-75°F), though I’ve noticed mustard prefers things slightly cooler (65-70°F).

Watering Technique

Now comes what I consider the most crucial secret to success: proper watering. Once roots reach the bottom of the tray (usually by day 3-5), I switch completely to bottom watering:

1. Add just enough water to the bottom tray (about ¼ to ½ inch)
2. Let the roots draw it up naturally
3. After about 15 minutes, pour off any remaining water to prevent root rot

This technique single-handedly eliminated most of the mold problems I used to experience!

Air circulation

Don’t overlook air circulation – especially for broccoli and pea shoots. I keep a small fan nearby and run it on low for about 15-20 minutes twice daily. This gentle air movement prevents mold formation and helps develop stronger stems. When I skipped this step, I definitely noticed the difference.

Harvesting

Most microgreens are ready to harvest when they’ve developed their first true leaves, typically between 7-14 days after planting. The smaller seed varieties like radish and mustard tend to mature faster (around 5-10 days), while larger seeds like sunflower and pea shoots usually take a bit longer.

The perfect time to harvest is when the plants look vibrant and have reached 2-3 inches in height. I use clean, sharp scissors and cut just above the growing medium, being careful not to include any of the growing mat in my harvest.

Storage

While I prefer harvesting right before meals for maximum freshness, you can refrigerate your harvest for 5-7 days. Just store them between slightly damp paper towels in a container with the lid slightly ajar to allow some airflow.

Maintaining Continuous Harvests

To keep a continuous harvest, I start new trays every 3-4 days. After harvesting, I remove the spent grow mat with roots, clean my trays, and start the process all over again. This rotation system ensures I always have fresh microgreens available.

The combination of quality growing mats and proper bottom watering completely transformed my success rate. Before figuring out this system, I was throwing away moldy trays regularly. Now I maintain steady harvests with almost no failures – my fridge is always stocked with fresh microgreens!

🆘 Troubleshooting Common Issues

Even with a perfect system, you might occasionally encounter some challenges. Here are solutions to the most common problems:

Mold Issues

If you see white fuzz on your seeds or growing medium:

• Increase air circulation immediately (use a small fan or move trays to a well-ventilated area)
• Reduce humidity by removing any dome or cover
• Ensure you’re not overwatering
• Try slightly less dense seeding next time

Leggy, Pale Seedlings

This indicates insufficient light:

• Move closer to a window or lower your grow light
• Ensure they’re getting at least 6-8 hours of good light daily
• Consider supplementing with an inexpensive LED grow light

Slow Germination

If your seeds are taking too long to sprout:

• Check the temperature (too cold slows germination)
• Ensure seeds have good contact with the moist growing medium
• Make sure pre-soaking time was sufficient for larger seeds
• Check seed quality and expiration date

Frequently Asked Questions