Hemp mat / Moisture mat Rectangle

In the Worm Café, Urban Worm, or Frutero, the rectangular hemp mat forms a cover over the entire surface of the active tray. It holds moisture in at the top of the bin, lets the bedding breathe, and makes fresh food scraps harder for fruit flies to reach.

You can skip the rectangular mat and use brown cardboard or a cotton cloth instead, but cardboard needs replacing far more often than high-density hemp (0.2–0.24 in, or 5–6 mm, thick). Our mat is 100% natural, biodegradable, and designed and made in France.

All our tips: What accessories does your worm composter need?

Yes, they love it. On the wide trays of the Worm Café, Urban Worm, or Frutero, the rectangular hemp mat covers the entire surface and holds in the moisture the worms need, so they come up to feed and work more efficiently.

Hemp is one of their favorite places to lay eggs. Small yellow cocoons appear on it, a sign of a growing colony. The rectangular mat also protects the worms from the cold and from temperature swings. Because it's all-natural, the worms gradually eat it.

Spread the rectangular hemp mat flat over the worms, covering the entire surface of the top tray. To feed, lift one side of the rectangle, add the food scraps and carbon-rich material under the mat, then lay it back down.

There's no need to soak it: put it in dry, and it will naturally absorb moisture from the fresh food scraps. If you like, mist it from time to time with diluted WORMboost to give your worms a boost.

The rectangular mat always stays with the active tray. When your tray is three-quarters full, set a new one on top (the Worm Café holds up to 5 trays) and move the mat up to it: this is where you'll add your food scraps from now on.

There's no need for one mat per tray; a single one is enough. If the old one is falling apart, you can leave it to break down in the tray below and lay a new mat in the top tray.

All our tips: How does a stacking-tray worm composter work?

The rectangular hemp mat lasts 2 to 3 months on average, sometimes 3 to 4, depending on the moisture level in your bin and the size of your worm population, which gradually eats it. That's simply the nature of a natural material, not a defect.

To replace it without disturbing the colony, simply lay the new rectangular mat on top of the old one: the worms will finish off whatever is left. If the old mat is still compact, crumble it slightly to make it easier for them to get through. Consider the packs of 5 or 10 if you use your Worm Café every day.