Sowing Seeds

Growing Seedlings in Hemp Fibre Cubes

Constantly on the lookout for the most eco-responsible gardening products possible, I’m sharing with you my experience of sowing in hemp fiber cubes. These little cubes, made from natural fibers, allow us to sow without using plastic containers.

Description

Produced and marketed in Canada under the Terrafibre brand name, hemp fiber cubes come in the form of 10″ x 20″ cushions (the size of a standard seed tray) divided into numerous smaller cubes (98 cubes for the 1.5″ x 1.5″ cushions). You can use the whole cushion at once, or cut it up according to the number of cubes you need and the shape of the tray you’ll be putting them in. For example, I find it wise to cut the cubes into groups of the same seeded variety.

Photo: Terrafibre.
The underside of the hemp fiber cubes. Photo: Terrafibre.

Use

Sowing is very easy with hemp fibre cubes, thanks to the pre-drilled hole in which the seed is placed. Once the seeds have been sown, water the cubes until they are saturated and then wait! In my experience, the use of a dome is not necessary. Since hemp fibers hold 1000 times their weight in water, the frequency of watering young seedlings is considerably lower than with potting soil. As the plants grow, liquid fertilization can be added, as the hemp fiber cubes have no nutrient reserves.

New shoots in hemp cubes. Photo: Julie Bussières, Vert Métal.
The seedlings now have two leaves and are ready for transplanting. Photo: Julie Bussières, Vert Métal.

Once the seedlings are well developed, we separate the cubes and transplant each cube and its seedling directly into a pot with potting soil. In my tests with tomato seedlings, using scissors to separate the cubes works perfectly, without damaging the roots. Depending on the sowing date, some crops, such as lettuces, can also be transplanted directly into the garden.

The material is ready to separate the cubes. Photo: Julie Bussières, Vert Métal.
Once the cubes have been separated. In my experience, scissors work well for cutting hemp fiber.Photo: Julie Bussières, Vert Métal.
Hemp cubes once transplanted. Photo: Julie Bussières, Vert Métal.
Some time later, we notice that the seedlings have grown well. Photo: Julie Bussières, Vert Métal.

To identify seedlings, the more traditional identification labels (plastic tags or wooden sticks) are almost impossible to prick into hemp. So you’ll need to find another system for identifying your crops, such as writing on the tray, using something thin and sharp – a toothpick, for example – or making a plan on paper.

Hydroponics

Hemp cubes can also be used in home hydroponic systems (indoor or tower gardens). Hemp fiber is also used in commercial hydroponics. In domestic hydroponic systems, filters need to be checked regularly. Hemp can release more particles into the water than other media used in hydroponic systems, so it can damage your system’s pump if it isn’t fitted with a good filter or if you don’t maintain it at least as regularly as prescribed.

Why Is Hemp an Eco-Friendly Material?

In addition to reducing the use of plastic containers, hemp fiber is also extremely environmentally friendly. In Canada, hemp is mainly grown for its seeds, which are used in the cosmetics and food industries. The seeds are extracted from the ends of the stalks, but the rest of the plant is a residue. Made from these crop residues, hemp fiber cubes are part of the circular economy, reusing the unused part of the plants. At the end of cultivation, hemp will decompose directly in the garden, and for other uses such as hydroponics, it can be composted, which is not the case for other materials such as rock wool.

Photo: Terrafibre.
Photo: Terrafibre.

Growing cubes are just one of the many products made from hemp fibers: mats for growing microfoams, animal bedding, insulating panels, anti-erosion mats, mulch… hemp is an eco-responsible product that is gaining recognition in horticulture and other fields.

Julie Bussière is a biologist specializing in peatland ecology. She is co-owner of Vert métal, an ecoresponsible horticultural boutique and manufacturer of gardening accessories. She is also the founder and manager of the Jardin communautaire de L'Ancienne-Lorette. Vert métal distinguishes itself by manufacturing plant walls and horticultural objects made of stainless steel. Also specializing in metalwork for landscaping, this eco-responsible company offers practical products for designers, landscapers, florists and all plant lovers.

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