Garden shredder buying guide: zero-bias guidelines

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Shredding plant waste is possible THE ultimate way to compress all that volume. Way less endless trips to the dump! You might even cut that back to zero – chipped waste proves quite handy in the garden, whether fresh or composted! Here are our non-biased tips on choosing the right garden shredder.

→ Read also: choosing the right chipper

1- Shredders: different tools for each ouptut

Getting the power of your shredder right is crucial. Prices swing wildly based on the motor type (electric or gas), grinding speed, and output size: it’s worth your while to carefully work out what you really need.

Shredder power:

Finer ouput material is better for composting and reducing volume. But if you’re mulching, go for a coarser, rougher grind. Pieces a few inches long, for instance (5-10 cm).

Electric motor powers range from 2 to 3.5 horsepower (1500W to 2500W). To chip up branches smaller than 1.5 inches across (40 mm), go for at least 2.5 horsepower (1800W). You’ll need a 16 Amps (16A) outlet, so make sure you can access that from the garden side. Maximum branch size for most home devices range from 1.2 to 2 inches (30 to 50 mm).

Chipping / shredding system:

Cutter/grinder systems come in either of 3 technologies: blade grinder, screw grinder, and rotor grinder. The latter two pack a punch, are quieter in operation, and also crush waste after shredding it.

• A blade shredder sports sharp blades attached to a horizontal disc. It can shred wood of 1.2 to 1.4 inches (30 to 35 mm), thanks to a high rotational speed. Some designs come with wide planer-type blades for an even finer grind. These tend to be somewhat noisier and sometimes shoot chips back upward: you must hold branches firmly. They easily handle soft material like perennial stems and vegetable peelings in addition to the small branches they’re marketed for. A check valve is recommended for clearing clumps. Of all grinder types, output is the finest. Maintaining sharp blades is crucial. They can also be replaced.
• The screw grinder gobbles up all kinds of plants. It usually comes with a reverse gear, quite handy in case of blockage. This design has the advantage of being fairly quiet.
• The rotor system, packs the strongest punch. It pulls waste downwards and grinds it with a toothed rotor that spins at a slow speed. Very quiet, this technology is a top choice for devouring waste from a large garden.

Blade, screw or rotor: which grinding system suits you?

The cutting mechanism decides how fine the chips come out, how much noise you make and how thick a branch you can push in. Here is how the three technologies described above compare.

Screw and rotor machines pack more punch and run quieter, while a blade machine wins on fineness of grind.

2- Other factors to consider

• Noise pollution from a shredder can range from 68 to 106 decibels. Ear protection might come in handy (and knowing when local ordinances allow you to operate it will smooth relationships with neighbors).
• Your shredder’s stability must be impeccable for safe operation. Usually, they come with wheels, a godsend for maneuvering around the garden especially when the device is heavy. Weight is anywhere from 26 to 110 pounds (between 12 and 50 kg), depending on the brand and make.
• A wide chute opening makes feeding in branched wood a breeze, but for blade grinders it leads to clogging. A side opening, featured on some devices, is helpful for loading wider, log-like branches.
• Safety matters: Choose a device equipped with a circuit breaker to avoid burning out the motor in case of a jam.

3- What to do with the ground-up material?

The shredded material, of course, can go straight into composting, making for fantastic soil mix.

However, you might miss out on a highly sought-after commodity today. For the past few decades, a new material has found common usage as mulch. It’s Ramial Chipped Wood (RCW). This is basically wood chippings from freshly cut branches that are less than 3 inches across (under 7 cm). It’s also known under the French acronym BRF (Bois Raméal Fragmenté).

→ Note that the quantity of chipped branches should not exceed more than 20% coniferous in this mix. Steer clear of thuja and eucalyptus as they kill off useful fungi involved in wood decomposition.

RCW noteworthy features:

Apart from reducing weeding and watering chores and preventing soil erosion, this new form of mulch brings along many benefits:

• revives soil life (fauna, fungi, bacteria),
• renders soil more pliable (improving its structure)
• and more fertile (richer in humus),
• boosts yields,
• diminishes pests and diseases.

How to use RCW or BRF?

Spread it as soon as possible after shredding to prevent it from starting to ferment.

Indeed, fermentation heat can kill microfauna and microflora contained in the product. To slow down its fermentation, form not too thick and well-aerated piles.

Spread RCW. preferably in fall or early winter, at the base of trees, in shrub beds and even in the vegetable garden. Bury it to 0.8-1.2 inches (to 2-3 cm), with a broadfork or rototiller, or simply form a mulch layer 1.2 to 2 inches thick (3 to 5 cm thick).

One thing to be aware of if you’re a first-time user: RCW decomposition initially causes a temporary 2-3-month “nitrogen sink” where the nutrient is less available. This could impede growth of young plants in spring.