Soil, coir, mats or water? What the research shows about microgreen growing media
The Microgreens World research database holds 300+ papers on what microgreens grow in. Here is what happened when researchers grew the same crops side by side in different media, what changed, and where the evidence stops.
The short answer
- There’s no single best medium. Peat, coco coir, vermiculite and most fiber mats all grew good crops in side-by-side trials. Di Gioia 2016 Hoang 2022
- The crop matters as much as the medium. Rocket gave its best yield on jute, and red basil its worst, in the same trial. Negri 2021
- The medium changes the details: nitrate, minerals and plant size. Peat-grown rapini held twice the nitrate of mat-grown rapini. Di Gioia 2016
- It changes food safety too. Germs lasted longer on hemp and Biostrate mats than in coir or peat, and hydroponic radish carried far more E. coli than peat-grown radish. Misra 2020 Xiao 2015
- Cheap, local and recycled materials can stand in for peat. Jute, recycled textile, coir blends and rice straw all held up in trials. Di Gioia 2016 Saurabh 2025
Which growing medium is best for microgreens?
Short version: most of them work. The differences show up in the details, and they flip from crop to crop.
Here’s what happened when researchers grew microgreens side by side in different media.
| Crops | Media compared | What they found | Source |
|---|---|---|---|
| Rapini | Peat, recycled textile mat, jute-kenaf mat, Sure to Grow (polyester) | Peat and both fiber mats averaged about 1.5 kg per square meter. The polyester mat came in 13% lower. | Di Gioia 2016 |
| Broccoli, red beet, black radish | Vermiculite, perlite, peat mix, filter paper, cotton textile, agril | Vermiculite and the peat mix gave the highest yields. | Balik 2024 |
| Five Brassica and radish crops | Four hydroponic pads, including hemp | Hemp mat grew the tallest, heaviest shoots, with the most potassium but the least nitrogen. | Li 2021 |
| Green basil, red basil, rocket | Vermiculite, coconut fiber, jute | Yields of 2 to 3 kg per square meter. The medium changed yield, dry matter and nitrate. | Bulgari 2021 |
| Purple cabbage | Four commercial substrates | The substrate made no difference to yield. The nutrient solution did. | Wieth 2019 |
| Brassica crops | Coir blends vs imported peat | Coir with lime and humic acid matched peat. Coir mixed with soil and sand raised disease. | Hoang 2022 |
| Seven crops | Soil vs cocopeat | Cocopeat gave better growth, yield and nutrient values than soil. | Gunjal 2024 |
Does the medium change nutrition?
Yes, for some things. The biggest effects show up in nitrate and minerals.
- Nitrate. Peat-grown rapini held about twice the nitrate of rapini grown on mats: 1,959 vs 940 mg per kg Di Gioia 2016. Coconut fiber changed nitrate levels in basil and rocket too Bulgari 2021.
- Minerals. Cabbage and lettuce microgreens grown on vermicompost held more of most minerals than ones grown on hydroponic pads Weber 2016. Compost-grown broccoli microgreens beat grown broccoli on more minerals than pad-grown ones did Weber 2017.
- Mixes and spacing. One seedling mix gave the highest yield at 12 seeds per cell. Another gave more vitamin C and glucosinolates at 4 seeds per cell Ntsoane 2023.
But don’t overread it. In the basil and rocket trial, the species drove most of the quality differences, not the medium Bulgari 2021. Want the nutrition side in full? See Are microgreens good for you?
Which media are safest?
This is where the medium matters most, and the research mostly comes from labs that add germs on purpose.
| What they tested | What they found | Source |
|---|---|---|
| Salmonella and Listeria on four mats, no plants | Both held steady for 10 days on hemp and Biostrate. They faded in coco coir and peat. | Misra 2020 |
| Germs moving into sunflower and pea shoots | More moved from Biostrate mats than from peat. | Deng 2021 |
| E. coli from seeds, peat mix vs hydroponic | Hydroponic radish carried far more E. coli on the leaves. | Xiao 2015 |
| Daikon on compost-soil, vermiculite-perlite, Biostrate pads | Compost-soil grown plants carried less Salmonella than pad-grown ones. | Chen 2023 |
| Natural contamination, no germs added | Peat-grown rapini had the most gut bacteria and the only E. coli found. | Di Gioia 2016 |
See the pattern? Mats and water systems tended to keep germs alive or move them more in the spiked lab tests. Peat did better there, but it carried the most bacteria when nothing was added. No medium is safe on its own. Clean seed and clean water matter more. The safety hub covers the rest.
Hydroponic microgreens: do they need soil at all?
No. Several trials grew strong crops with no soil. Basil and rocket floating on water over vermiculite, coconut fiber or jute yielded 2 to 3 kg per square meter Bulgari 2021. Hemp, jute and other pads all produced harvestable crops Li 2021.
Two trade-offs show up. In both of Weber’s studies, compost-grown microgreens came out ahead of pad-grown ones on minerals Weber 2016 Weber 2017. And the water system carried more E. coli in the one direct test Xiao 2015. For the how-to side, see growing microgreens without soil.
Can you replace peat?
Peat and synthetic mats are the standard, but both cost money and neither is renewable Di Gioia 2016. These swaps held up in trials:
- Jute-kenaf and recycled textile mats matched peat on yield, with lower nitrate Di Gioia 2016.
- Coco coir with lime and humic acid worked as well as imported peat Hoang 2022.
- Coir dust mixed with leaf compost gave the top sunflower yield. Most waste-based mixes carried Bacillus cereus above the standard limit, though, except peat and plain coir for sunflower Thepsilvisut 2023.
- Treated rice straw held plenty of water, though less than cocopeat, and grew the longest, heaviest cabbage. Vermiculite gave more iron, zinc and manganese Saurabh 2025.
What do growers actually use?
In a survey of 176 US microgreen growers, peat, soil and coco coir were the top three media Misra 2021. Larger farms were more likely to test their growing media at least once a year.
What the research doesn’t show yet
- Most trials test only a few crops. Results flip by species, so a winner for rocket may lose for basil Negri 2021.
- Few compare cost. The papers report yield and nutrients. Almost none weigh the price of the medium against the crop.
- The safety findings are mostly lab tests. Germs were added on purpose, at high levels.
- Brand and batch vary. “Coco coir” or “hemp mat” in one paper may not match the bag you buy.
Key papers to start with
Eight papers that carry most of the weight on this page. Each title opens the paper at the publisher.
Physicochemical, agronomical and microbiological evaluation of alternative growing media for the production of rapini microgreens
Peat vs three mats on yield, nitrate and germs. The most cited media comparison in the database.
Quality evaluation of indoor-grown microgreens cultivated on three different substrates
Vermiculite, coconut fiber and jute in a floating system under LEDs.
Shoot production and mineral nutrients of five microgreens as affected by hydroponic substrate type and post-emergent fertilization
Four hydroponic pads. Hemp grew the biggest shoots.
The performance of growing-media-shaped microgreens: The growth, yield, and nutrient profiles of broccoli, red beet, and black radish
Six media side by side. Vermiculite and peat mix led on yield.
Survival of Salmonella Javiana and Listeria monocytogenes is dependent on type of soil-free microgreen cultivation matrix
Germs lasted longest on hemp and Biostrate mats.
Proliferation of Escherichia coli O157:H7 in soil-substitute and hydroponic microgreen production systems
Hydroponic radish carried far more E. coli than peat-grown radish.
Nutrient content of cabbage and lettuce microgreens grown on vermicompost and hydroponic growing pads
Vermicompost beat hydroponic pads on most minerals.
Efficacy of agricultural and food wastes as the growing media for sunflower and water spinach microgreens production
Waste-based swaps for peat, with yields and a food safety check.
Newest papers on this topic
- Newest papers load from the research database.
Questions people ask
What is the best growing medium for microgreens?
No single medium wins. In side-by-side trials, peat, coco coir, vermiculite and most fiber mats all grew good crops. Results changed by crop, so the best choice depends on what you grow, your budget and how you water.
Can you grow microgreens without soil?
Yes. Trials grew strong crops on coconut fiber, vermiculite, jute, hemp and other pads, including floating hydroponic systems with yields of 2 to 3 kg per square meter.
Are hemp mats good for microgreens?
For growth, yes. Hemp mats grew the tallest, heaviest shoots of four pads in one trial. For food safety, take care: Salmonella and Listeria lasted longer on hemp mats than in coir or peat in a lab test.
Is coco coir better than peat for microgreens?
Usually about the same. Treated coir matched imported peat in one trial, and cocopeat beat plain soil in another. Coir is renewable and often cheaper where peat must be imported.
Are hydroponic microgreens as healthy as soil-grown?
They can be lower in some minerals. Two studies found more minerals in compost-grown microgreens than in ones grown on hydroponic pads. Vitamins and other compounds depended more on the crop.
Which growing medium is safest?
None is safe on its own. In lab tests, germs lasted longer on hemp and Biostrate mats and spread more in a water system than in peat. But peat carried the most bacteria when nothing was added. Clean seed and clean water matter most.
Keep reading
Sources
- Di Gioia, De Bellis, Mininni, et al. (2016). Physicochemical, agronomical and microbiological evaluation of alternative growing media for the production of rapini (Brassica rapa L.) microgreens. Journal of the Science of Food and Agriculture. doi.org/10.1002/jsfa.7852
- Bulgari, Negri, Santoro & Ferrante (2021). Quality evaluation of indoor-grown microgreens cultivated on three different substrates. Horticulturae. doi.org/10.3390/horticulturae7050096
- Negri, Bulgari, Santoro & Ferrante (2021). Evaluation of different growing substrates for microgreens production. Acta Horticulturae. doi.org/10.17660/actahortic.2021.1305.16
- Li, Lalk, Arthur, et al. (2021). Shoot production and mineral nutrients of five microgreens as affected by hydroponic substrate type and post-emergent fertilization. Horticulturae. doi.org/10.3390/horticulturae7060129
- Balik, Dasgan, Ikiz & Gruda (2024). The performance of growing-media-shaped microgreens: The growth, yield, and nutrient profiles of broccoli, red beet, and black radish. Horticulturae. doi.org/10.3390/horticulturae10121289
- Wieth, Pinheiro & Duarte (2019). Purple cabbage microgreens grown in different substrates and nutritive solution concentrations. Revista Caatinga. doi.org/10.1590/1983-21252019v32n414rc
- Hoang & Vu (2022). Selection of suitable growing substrates and quality assessment of Brassica microgreens cultivated in greenhouse. Academia Journal of Biology. doi.org/10.15625/2615-9023/16833
- Thepsilvisut, Sukree, Chutimanukul, et al. (2023). Efficacy of agricultural and food wastes as the growing media for sunflower and water spinach microgreens production. Horticulturae. doi.org/10.3390/horticulturae9080876
- Saurabh, Roy, Shubha, et al. (2025). Transforming rice straw into eco-friendly growing medium for microgreens: a solution for agricultural waste management. Frontiers in Sustainable Food Systems. doi.org/10.3389/fsufs.2025.1556396
- Weber (2016). Nutrient content of cabbage and lettuce microgreens grown on vermicompost and hydroponic growing pads. Journal of Horticulture. doi.org/10.4172/2376-0354.1000190
- Weber (2017). Broccoli microgreens: A mineral-rich crop that can diversify food systems. Frontiers in Nutrition. doi.org/10.3389/fnut.2017.00007
- Ntsoane, Manhivi, Shoko, et al. (2023). The phytonutrient content and yield of Brassica microgreens grown in soilless media with different seed densities. Horticulturae. doi.org/10.3390/horticulturae9111218
- Misra & Gibson (2020). Survival of Salmonella enterica subsp. enterica serovar Javiana and Listeria monocytogenes is dependent on type of soil-free microgreen cultivation matrix. Journal of Applied Microbiology. doi.org/10.1111/jam.14696
- Xiao, Bauchan, Nichols-Russell, et al. (2015). Proliferation of Escherichia coli O157:H7 in soil-substitute and hydroponic microgreen production systems. Journal of Food Protection. doi.org/10.4315/0362-028x.jfp-15-063
- Deng, Misra, Baker & Gibson (2021). Persistence and transfer of foodborne pathogens to sunflower and pea shoot microgreens during production in soil-free cultivation matrix. Horticulturae. doi.org/10.3390/horticulturae7110446
- Chen, Yin & Patel (2023). Influence of contamination source and cultivation matrix on survival of Escherichia coli O157:H7 and Salmonella enterica on daikon microgreens. LWT. doi.org/10.1016/j.lwt.2023.115165
- Misra & Gibson (2021). Characterization of microgreen growing operations and associated food safety practices. Food Protection Trends. doi.org/10.4315/1541-9576-41.1.56
- Gunjal, Singh, Kaur, et al. (2024). Comparative analysis of morphological, nutritional, and bioactive properties of selected microgreens in alternative growing medium. South African Journal of Botany. doi.org/10.1016/j.sajb.2023.12.038
Read the papers yourself
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Search the growing media papersThis page summarizes published research for education. Results come from specific crops, media and conditions, and may differ in your own setup.
