Choosing the right growing medium is one of the most consequential decisions a microgreens grower can make. It affects germination rates, root development, moisture management, harvest cleanliness, and the overall sustainability of your operation — whether you are growing on a single tray at home or scaling across hundreds of flats in a commercial facility.
For years, soil was the default. Then coco coir emerged as a cleaner alternative. Hydroponic pads followed. Each medium brought improvements, but also limitations. Today, there is a growing consensus among serious microgreens growers: hemp fibre grow mats represent the most complete solution available.
The growing media landscape: what are your options?
Before evaluating which medium is best, it helps to understand what the main contenders are and how they work.
Soil and potting mix
Soil is familiar, nutritious, and forgiving for beginners. However, it introduces significant drawbacks in a microgreens context: it is messy to handle, prone to harbouring pests and fungus gnats, and can make harvesting more difficult when roots cling to the substrate. Soil also adds weight to trays and complicates cleanup between grows.
Coconut coir
Coco coir is a popular soil alternative derived from coconut husks. It is lighter than soil, relatively clean, and has decent water retention. However, it comes with a number of limitations worth considering. It is not biodegradable in a meaningful timeframe, quality can vary significantly between suppliers, and it still requires hydration and preparation before use. There is also the question of carbon footprint — coconut husks are a byproduct of tropical agriculture, meaning coco coir is typically shipped from Southeast Asia or Sri Lanka before it reaches a Canadian grow room. For growers who factor environmental impact into their purchasing decisions, the shipping distance is a meaningful consideration when a locally grown, locally manufactured alternative exists.
Rockwool / stonewool
Rockwool is widely used in hydroponic systems. It provides excellent structural support and moisture retention, but it is made from spun volcanic rock fibres using an energy-intensive process. It is not biodegradable, can irritate skin and lungs during handling, and raises concerns about sustainable disposal after use.
Burlap and jute mats
Natural fibre mats made from jute have been used as a growing medium, but they tend to be loosely structured. Roots often slide along the surface rather than anchoring into the fibres, which can compromise plant stability and result in uneven stands during the blackout phase.
Hemp fibre grow mats
Hemp grow mats — including Terra Fibre's own product line — are produced from the fibrous byproduct of industrial hemp cultivation. The fibres are separated through a chemical-free decortication process, then needle-punched into a reinforced, biodegradable mat. The result is a consistent, clean, and structurally sound growing medium with exceptional water retention and root support.
Head-to-head comparison
The table below evaluates each major medium across five key performance criteria:
What makes hemp fibre the superior choice?
The comparison table highlights the performance differences at a glance, but the reasons behind each result are worth understanding in depth.
1. Water retention that works with your grow, not against it
Hemp fibres are capable of absorbing and holding up to 1,050% of their own weight in water. This extraordinary water-holding capacity means seeds stay hydrated throughout the critical germination window without requiring constant attention. Unlike soil, which can compact and create uneven moisture distribution, hemp mats wick moisture evenly across the entire surface — ensuring consistent germination across every seed.
2. Root anchoring that supports strong, upright growth
One of the most important — and often overlooked — factors in microgreens production is root anchoring. The loose, fibrous weave of a hemp grow mat allows radicles (the first root emergence from a seed) to penetrate and grip the medium immediately. This early anchoring provides the structural stability needed for seedlings to lift their seed casings during the blackout phase, and to grow upright and uniform through to harvest.
This is a meaningful advantage over jute mats, where roots frequently slide along the surface rather than penetrating the medium, and over coco coir, which can compact and impede root development.
3. Harvesting is cleaner — and faster
Harvest cleanliness matters enormously, both for the quality of the end product and for the efficiency of your operation. With soil-grown microgreens, roots grip substrate and often bring soil up with the cut stems, requiring additional washing and introducing variability in the final product. Hemp grow mats produce a clean separation at harvest — roots remain embedded in the mat, greens lift away cleanly, and the cut surface is free of debris.
For commercial growers in particular, this cleanliness translates directly into time saved per tray and a more consistent, market-ready product.
4. Sustainability without compromise
Terra Fibre grow mats are made from 100% industrial hemp fibre, grown, processed, and manufactured in Canada. The decortication process uses no chemicals, and the finished mat is fully biodegradable and compostable. At the end of its useful life, the mat — roots and all — can go directly into a compost bin.
Compare this to rockwool, which cannot be composted or recycled and raises disposal challenges, or coco coir, which is often shipped long distances and degrades only partially over time.
5. pH neutral, chemical-free
Terra Fibre hemp mats are pH neutral and free from phenols, dust, and added chemicals. This is particularly relevant for growers following organic practices, or those supplying to markets where input traceability matters. With soil, organic certification of the medium itself requires additional verification. With a hemp grow mat, the medium is inherently clean.
6. Compatible with any growing system
Terra Fibre grow mats are available in the standard 10" x 20" format to fit 1020 trays, as well as 5" x 5" sizes and bulk rolls for custom cutting. They are compatible with standard bottom-watering trays, stacked blackout setups, and vertical hydroponic systems — making them suitable for every scale of operation from a home kitchen setup to a multi-rack commercial grow room.
The case for starting with grow mats from day one
Many growers begin with soil because it feels familiar and requires no additional purchase. But growers who make the switch to hemp grow mats consistently report that they wish they had started there. The benefits compound quickly:
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Cleaner workspace with no soil spillage or dust
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Faster tray turnover — mats are lighter and easier to move
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More consistent germination across the mat surface
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Simpler composting at end of use — no contaminated soil to dispose of
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Less risk of soil-borne pests such as fungus gnats
PRO TIP
If you are new to hemp grow mats, begin with a species known for reliable germination — radish, broccoli, or sunflower. These varieties anchor quickly into hemp fibre and provide an excellent benchmark for comparing your results against soil-grown trays.
The growing medium you choose shapes every aspect of your microgreens operation — from the first hours of germination through to the quality of what ends up on the plate. Soil remains a viable option for beginners willing to manage its limitations. But for growers who prioritise consistency, cleanliness, root development, and sustainability, hemp grow mats are the clear step forward.
Terra Fibre grow mats are made in Canada from 100% industrial hemp fibre, without chemicals, and without compromise. Whether you are setting up your first home tray or optimising a commercial facility, they offer the performance foundation that serious microgreens growing demands.
