Most commercial growers buy whatever grow mat their supplier stocks, discover it doesn't quite suit the crop, and work around it. They adjust the seeding density, water more often, accept a germination rate they aren't happy with, and assume that is simply what hemp mats do.
Usually it isn't. It's what that mat does.
A grow mat is a manufactured component with a specification, in the same way a tray or a propagation dome is. Weight, dimensions, reinforcement and treatment are all variables, and we set them per run. If you are growing at volume and the mat you're using was chosen for you by a retail shelf, there is a good chance a different specification would do the job better.
Match the weight to the seed
The single most useful thing we can tell a commercial grower is this: bigger seed wants a heavier mat.
Think about what a pea or a sunflower seed is doing in the first 48 hours. It is several times the mass of a broccoli or radish seed, it takes up far more water, and it pushes hard against the medium as it swells and sends a root down. A light mat under that load holds less water relative to the demand placed on it, and gives the root less to grip. Growers see it as patchy germination, seeds sitting proud of the surface, or a mat that dries out between waterings.
We make mats from 300 to 1200 gsm. Three weights are standard and held in stock:
If you are running sunflower or pea shoots on a 300 gsm mat, that is the first thing to change.
The rest of your process stays as it is.
And to the length of the crop
Seed size is the first variable. Crop duration is the second, and it points the same way.
A microgreen tray is cut in seven to fourteen days, and over that window the mat is mostly a moisture reservoir and a place to root. Hold a plant for longer than that — propagation, transplant plugs, anything carried for weeks rather than days — and the mat stops being a short-term reservoir and starts being the growing medium proper.
Heavier weights have been used that way: as the medium for longer-growing plants, not just a germination surface. If that is what you are doing, the specification conversation is different from the microgreens one, and it is worth having before you commit to a format.
Size and shape
Three sizes are standard. Note the actual dimensions — the standard tray sizes are cut slightly under so the mat drops in without binding at the corners.
Beyond that, we cut to order:
• Smaller than 5″ × 5″ — for plug trays and small-cell propagation
• Larger than standard — we are currently producing a 22″ × 33″ format for a customer whose benches don't take a 10 × 20
• Custom shapes — not only rectangles, if your system needs something else
This is the part most growers don't think to ask about. If your trays, benches or channels are a non-standard size, the usual answer is to cut mats down by hand and accept the waste. You don't have to. A run cut to your dimension removes the labour and the offcuts at the same time.
Reinforcement: when you need a scrim
A scrim is a light reinforcing layer that holds the mat together under handling. Two options:
BioScrim. The default. Keeps the mat fully biodegradable, which matters if the spent mat is going to compost or back onto a field.
Rayon. Specified on the 10″ × 120′ roll, and worth considering wherever durability is the constraint rather than the mat's performance in the tray. It earns its place when:
- The mat is large, so there is more of it to carry its own weight
- The mats get handled a lot — moved, stacked, loaded, repositioned
- The mats are pre-soaked before seeding, which is when a mat is at its most fragile
If your crew is pre-soaking trays of 10 × 20s and losing mats to tearing, that is a reinforcement question, not a technique problem.
Heat treatment
Mats can be heat treated to sterilize them before they ship.
For a home grower this is a nicety. In a commercial greenhouse running dense trays in a warm, humid room on a tight rotation, it is a different matter: it removes one variable from a hygiene program where a single contaminated batch can cost a full crop cycle.
If your facility has a hygiene protocol you have to document, tell us — it is worth getting specified at the order stage rather than managed on arrival.
Specifying a run
Five things get us to a recommendation and a price:
- What you're growing — crops and seed sizes, and whether the mix changes through the year
- Your tray or bench dimension — the actual internal measurement, not the nominal size
- How long the crop sits — days to harvest, or weeks if you're propagating
- How the mats get handled — pre-soaked, stacked, moved between rooms
- Volume and cadence — mats per week or per month, and whether it's a trial or ongoing
We manufacture in Drayton Valley, Alberta, which means short runs and custom formats are a production decision rather than an import problem. If you want to test a weight before committing, say so — that is a normal way to start.
