Microgreens are small but powerful plants harvested at an early stage for their intense flavor, color, and nutritional content. From chefs to health-conscious home gardeners, these tiny greens have found a place on plates across the world. What makes microgreens even more accessible is the ability to grow them without soil. That’s right—whether you're in a small apartment, a kitchen with limited space, or you're trying to keep things clean and simple, soilless microgreen cultivation is an ideal solution.
Learning how to grow microgreens without soil opens up possibilities for anyone to produce fresh greens year-round. This article dives deep into the process, materials, growing mediums, lighting, harvesting, and troubleshooting so you can successfully grow vibrant microgreens from your countertop, windowsill, or shelf.
What Are Microgreens?
Microgreens are the young seedlings of herbs and vegetables, harvested just after the cotyledon leaves (the first set of leaves) appear, and often before the first true leaves develop. They’re not sprouts and they’re not baby greens—they’re somewhere in between.
Unlike sprouts, microgreens require light and airflow, and they grow upright. Their roots are anchored in a medium (even when it's not soil), and you harvest the above-ground parts.
Common Microgreens to Grow Without Soil:
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Broccoli
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Kale
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Arugula
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Radish
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Mustard
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Sunflower
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Pea shoots
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Basil
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Cilantro
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Beet
Benefits of Growing Microgreens Without Soil
Soilless cultivation provides several advantages, especially for indoor gardeners.
1. Clean and Mess-Free
No dealing with dirt, no soil spills, and no worry about cleaning stubborn soil stains from trays or surfaces.
2. Reduces Risk of Contamination
Without soil, there's less chance of pathogens like mold or bacteria developing if proper hygiene is maintained.
3. Easier Harvest
Cutting clean greens above the mat or medium is simpler and more efficient than picking them out of soil.
4. Ideal for Small Spaces
Soilless setups are compact and easy to manage in kitchens, shelves, or on countertops.
What You Need to Grow Microgreens Without Soil
Let’s break down the essential tools and supplies required.
1. Growing Trays
Flat trays with shallow sides are ideal. Choose trays approximately 10”x20” with or without holes depending on your watering method.
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With holes: Good for bottom-watering setups.
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Without holes: Useful if you plan to mist or pour water manually.
You’ll need at least two trays—one to hold the growing medium and one beneath to catch water.
2. Growing Medium (Soilless Options)
You still need a substrate to support the roots. Some excellent soilless media include:
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Coconut coir mats: Biodegradable, holds moisture well.
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Hemp mats: Sustainable and clean, ideal for delicate seeds.
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Bamboo fiber mats: Another eco-friendly and sterile option.
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Grow felt or synthetic mats: Durable and reusable, often made of food-safe polyester.
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Paper towels or unbleached paper: Suitable for experimentation or ultra-low budget methods.
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Hydroponic grow pads: Designed for professional soilless production.
Each medium has its strengths. Coconut coir and hemp mats are most popular for their ease of use and consistency.
3. Seeds
Use seeds specifically labeled for microgreens. These are untreated, non-GMO, and germinate well in dense sowings.
4. Light Source
Microgreens require light to thrive. Depending on your space and budget, you can choose:
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Natural sunlight (south-facing window is best)
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LED grow lights (full-spectrum, 12–16 hours per day)
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Fluorescent lights (T5 or similar tubes work well)
5. Spray Bottle or Misting Tool
For maintaining moisture during germination and growth.
6. Humidity Dome or Cover
Clear plastic domes or even lids help retain moisture during the first few days.
Step-by-Step Guide to Growing Microgreens Without Soil
Step 1: Prepare the Tray and Growing Medium
Start by placing your grow mat or pad into the bottom of the tray. Cut it to size if needed. Pre-moisten the mat with a spray bottle or by soaking in clean water. If using paper towels, fold them into 2–3 layers and dampen them evenly.
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Do not over-saturate.
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Ensure uniform coverage with no dry patches.
Step 2: Seed Selection and Soaking
Some seeds benefit from a short soak (4–8 hours) before sowing, especially:
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Sunflower
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Pea
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Beet
Smaller seeds like broccoli, arugula, or basil usually don’t require soaking.
Rinse soaked seeds thoroughly in clean water before planting.
Step 3: Sowing Seeds
Sprinkle seeds evenly over the moist grow mat. A dense sowing is typical for microgreens, but avoid overcrowding, which can lead to mold.
Use a spoon or fingers to spread them evenly. Press them gently into the mat so they make contact but remain exposed to air.
Step 4: Cover for Germination
Cover the tray with another tray (or use a humidity dome) to block out light and trap moisture. This simulates soil conditions and helps seeds sprout uniformly.
Place the tray in a dark, warm place for 2–4 days. Most microgreens germinate well between 65°F and 75°F (18°C–24°C).
Step 5: Watering Without Soil
While your seeds are covered, mist them 1–2 times per day. The key is to keep the mat damp but not soggy. Once germination is visible, remove the cover and expose them to light.
Switch to bottom-watering if using trays with holes. This prevents stem rot and keeps foliage dry.
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Add 1/4 to 1/2 inch of water to the bottom tray.
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Let the growing tray absorb moisture from below.
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Empty any excess water after 20–30 minutes.
Repeat as needed to keep the mat damp.
Step 6: Lighting and Airflow
After sprouting, your microgreens need strong light to grow upright and develop chlorophyll.
Light Tips:
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Place grow lights 4–6 inches above the greens.
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Provide 12–16 hours of light daily.
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Rotate trays if using windows to avoid bending toward the sun.
Good air circulation is vital to reduce mold risks. Consider placing a small fan nearby to keep the air gently moving.
Step 7: Harvesting Microgreens
Most microgreens are ready to harvest 7 to 14 days after planting, depending on the variety.
Harvest When:
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Cotyledons are fully developed.
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First true leaves begin to appear.
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Stems are 2–4 inches tall (varies by type).
Use clean scissors or a sharp knife to cut the greens just above the mat. Avoid pulling roots or disturbing the substrate.
Step 8: Rinse, Dry, and Store
After harvesting, rinse your microgreens gently in cool water to remove any seed hulls. Use a salad spinner or clean kitchen towel to dry them thoroughly.
Store in a sealed container in the refrigerator. Most microgreens stay fresh for 5–7 days when kept dry and cool.
Reusing the Growing Medium
Depending on what you used:
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Single-use mats (hemp, paper towels) should be composted or discarded.
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Synthetic mats can be rinsed and sanitized with a mild bleach solution and reused.
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Avoid reusing mats that had mold issues or poor drainage.
Common Challenges and Solutions
1. Mold or Mildew
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Cause: High humidity, lack of airflow, overwatering.
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Solution: Use a fan, reduce watering, sterilize trays between uses.
2. Uneven Germination
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Cause: Inconsistent moisture, poor seed contact with the mat.
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Solution: Ensure even seeding, press seeds into the mat, and mist regularly.
3. Weak or Leggy Growth
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Cause: Inadequate light.
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Solution: Move trays closer to light, increase duration, or use stronger lights.
4. Seeds Not Sprouting
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Cause: Old seeds, dry mat, incorrect temperature.
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Solution: Use fresh seeds, pre-soak large ones, monitor temperature.
Microgreen Nutrition: Why Soilless Doesn’t Mean Less
You might wonder: do microgreens grown without soil still offer the same benefits?
Yes—studies have shown that hydroponically grown microgreens are just as nutrient-dense as those grown in soil. Since the plant only grows to the cotyledon stage, it doesn’t pull extensive minerals from the medium.
Instead, its nutrition comes from the seed’s stored energy, making even paper towel-grown greens healthy and rich in:
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Vitamins A, C, K, E
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Minerals like potassium, iron, and magnesium
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Antioxidants and polyphenols
Scaling Up: Growing Microgreens Without Soil for Profit
Many small farms and urban gardeners are now growing microgreens commercially using hydroponic methods. The low setup cost, fast turnaround, and high market value make it a profitable venture.
Tips for Small-Scale Commercial Setup:
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Use vertical shelving with LED grow lights.
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Automate watering with capillary mats or ebb-and-flow systems.
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Maintain strict hygiene to avoid crop loss.
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Diversify with specialty greens like red cabbage, sorrel, or nasturtium.
Final Thoughts
Learning how to grow microgreens without soil is a skill that blends simplicity with innovation. From clean harvests to compact setups, the method offers a modern approach to self-sufficiency and fresh nutrition. Whether you're supplementing your diet with fresh greens, teaching children about food, or even building a small business, soilless microgreens are accessible, affordable, and satisfying to grow.
All it takes is a tray, a mat, some light, and a few seeds—and in just two weeks, you can have a vibrant harvest right from your windowsill.