The Reusable Silicone Microgreen Grow Medium – 1.2mm, 10x20 is a food-grade silicone mat that replaces soil and coco coir for home and commercial growers who want a clean, soil-free setup. Pre-cut to 19.65" x 9.5" to fit standard 10x20 trays, the 1.2mm hole pattern holds small seeds while supporting moisture retention and root aeration. Reusable for 20–30+ grow cycles with proper care.
Why choose silicone for your 10x20 trays?
Unlike soil and coco coir that get replaced after every harvest, one silicone mat covers 20–30+ grows — cutting waste and ongoing supply costs. The flexible surface makes seeding, handling, and cleanup easier than rigid materials, and trims to size with household scissors for custom trays.
Specifications
- Material: food-grade, platinum-cured silicone with a fiberglass core
- Compliance: 3rd-party tested for FDA compliance; LFGB tested & compliant
- Hole size: 1.2mm (sized for small seeds; supports root development)
- Pre-cut dimensions: 19.65" x 9.5"
- Fits: standard 10x20 microgreen trays (including Bootstrap Farmer 10x20)
- Reusability: 20–30+ grow cycles per sheet with proper care
- Growing method: soil-free / hydroponic (add liquid fertilizer — the medium is inert)
- Customizable: trim with household scissors for custom tray sizes
- Cleaning: warm water + silicone-safe, food-safe dish soap
- Sanitizing: boiling water, 1–2 minute soak, then air dry fully
- Storage: lay flat to prevent creases
- Warranty: 1 year (manufacturing defects, material failures, premature deterioration)
- Shipping: U.S. only; free over $65
Best for
- Growers who want a reusable, low-waste medium instead of buying soil or coco coir each harvest
- Small-seeded crops: broccoli, kale, cabbage, arugula, radish, kohlrabi, mustard, and most brassicas
- Clean indoor setups, home or commercial, where soil mess and disposal are a problem
Not for
- Swiss chard, beets, and cilantro — these perform better in soil or coco coir
- Peas with aggressive root systems — often best grown bare on a mesh tray with no medium
- Growers wanting a nutrient-carrying medium — silicone is inert, so you supply liquid fertilizer
Seed compatibility
✅ Works well with:
Sunflower, Pea, Radish, Broccoli, Kale, Cabbage, Arugula, Basil, Mustard Greens, Kohlrabi, and most Brassica varieties.
⚠️ More challenging:
Amaranth can grow successfully at 75°F with a seedling heat mat during germination. Very fine seeds may need adjustments depending on your setup.
❌ Not recommended:
Swiss Chard, Beets, and Cilantro (these perform better in soil or coco coir).
💡 Best without a medium:
Pea varieties with aggressive root systems often perform best directly on mesh trays without a grow medium.
Detailed seed compatibility infographics are included in the product photos.
Care & maintenance
Cleaning: After harvest, use our Microgreen Medium Scraper/Cleaning Tool to remove root residue. Wash with warm water and a free-and-clear dish soap (or another silicone-safe, food-safe soap). The flexible surface makes root removal quicker than rigid materials.
Sanitizing between grows: For deeper sanitation, carefully pour boiling water over the mat or submerge it for 1–2 minutes (use caution with hot water). Allow the mat to air dry fully before reuse. Many growers sanitize in batches after harvest.
For more tips, stain troubleshooting, and long-term care, read our complete silicone care guide.
FAQ
What trays does the 1.2mm 10x20 silicone medium fit? It's pre-cut to 19.65" x 9.5" and drops into standard 10x20 microgreen trays, including Bootstrap Farmer trays.
Which microgreens grow well on it? Small-seeded crops do best: broccoli, kale, cabbage, arugula, radish, kohlrabi, mustard, sunflower, and most brassicas.
Which seeds aren't recommended? Swiss chard, beets, and cilantro grow better in soil or coco coir. Peas with aggressive roots do best bare on a mesh tray.
How many times can I reuse it? 20 to 30+ grow cycles per sheet with proper cleaning and flat storage. Commercial use may need more frequent replacement.
Do I still need fertilizer? Yes. The silicone is inert and adds no nutrients, so feed with a liquid fertilizer the same way you would on coco coir.
How do I clean it? Rinse with warm water and a silicone-safe, food-safe dish soap. A medium scraper tool removes root residue quickly.
How do I sanitize between grows? Pour boiling water over the mat or submerge it for 1–2 minutes, then air dry fully before reuse.
Is the silicone food-safe? Yes — it's food-grade, platinum-cured silicone, 3rd-party tested for FDA compliance and LFGB compliant.
Can I cut it to a custom size? Yes — trim it with household scissors. Replace the mat if cuts, tears, or wear expose or compromise the fiberglass core.
Does staining affect performance? No. Some seeds cause natural surface staining on the silicone, which doesn't affect how it grows.
How should I store it? Lay it flat, ideally inside a spare 10x20 or 10x10 tray, to prevent creases and folds.
Do you ship internationally? We currently ship within the U.S. and Canada only. Free U.S. shipping over $65.
Start small, scale confidently
New to reusable grow mediums? Start with a 2-pack to test the setup in your environment. Once you're dialed in, 10-packs offer better value for higher-volume growing.
Want to compare materials? Try our 10x10 Sampler Pack featuring both silicone and stainless steel samples to find your match.
Discontinued: stainless steel 10x20 version
As of January 2026, we've discontinued the stainless-steel 10x20 grow medium indefinitely to focus on silicone, the preferred option for most growers. We still carry the 10x10 Stainless Steel Reusable Grow Medium.
More sizes available
Looking for different tray sizes? We offer silicone and stainless steel in multiple pre-cut dimensions. Browse all reusable grow medium sizes here.
1-year warranty
All silicone mesh screens are backed by our 1-year warranty, covering manufacturing defects, material failures, and premature deterioration under normal use.
You may find these blogs helpful:
- Which Microgreen Seeds Work on Reusable Grow Mediums?
- Silicone Reusable Microgreen Grow Medium – Complete Overview
- How to Grow Microgreens in 10x20 Trays: Reusables, Soil, and Coco Coir
- How to Clean and Sanitize Microgreen Trays and Reusable Grow Mediums
- Microgreens and Mold: Prevention, Identification, and Treatment
- Knowing the Right Time to Transition Microgreen Trays from Weight to Blackout
- Common Mistakes When Growing Microgreens (And How to Avoid Them)
- Looking for the Best Microgreen Growing Advice? Start with On The Grow
- Frequently Asked Questions
Important product disclaimers
- Please review our Reusable Grow Medium Safety Disclaimer before purchasing.
- Commercial use may require more frequent replacement and quicker deterioration.
- Trays, seeds, and other items shown in photos are NOT included.
- Silicone staining: some seed varieties may cause natural staining on the surface — this doesn't affect performance.
- Fiberglass core: replace your mat if you notice tears, deep cuts, or significant wear that could compromise the fiberglass core. Learn more about replacement timing.
- Variable results: growing success depends on your environment, experience, and methods. Test with small packs before committing to larger quantities.
- Nutritional content disclaimer: this product is an inert growing medium that does not add or remove nutrients from your crops. We make NO claims about nutritional content or nutrient density of microgreens grown using it. Nutrient density depends on factors outside our control — seed variety, water quality, light, fertilizers, and growing conditions — not the medium itself. We have not conducted laboratory testing and are not nutritionists. For the complete nutritional disclaimer, see our Safety Disclaimer page.