Torsion Weeders

Mode of Action	uproots weeds
Required Bed Preparation	loose, level soil relatively dry and workable not effective on heavy or hard soils as clay increases, cultivation efficacy typically decreases
Row Spacing	10" minimum
Optimum Weed Stage	cotyledon - 2 true leaves
Optimum Crops	crops must be extremely well-rooted with sufficient row spacing
Optimum Crop Stage	2+ true leaves, very well-rooted
Speed	2 - 7 mph
Settings	torsions must be relatively centered on crop as tip distance increase, cultivation aggressiveness decreases crop damage will typically increase with tractor speed higher disturbance if torsions are set to overlap, but crops must be well-rooted to avoid injury a slight downward angle for the torsions is optimal 7 mm torsions for lighter soils, 10 mm torsions for heavier soils
Crop Damage	crops will be uprooted if not sufficiently established
Combinations with Other Tools	especially effective combined with interrow tools such as hoes, tines, sweeps, side knives, etc can be combined with finger weeders to control larger intrarow weeds can stack effectively in the order of torsion-finger-row tine harrows (see Brown & Gallandt below)

Modified from van der Schans et al. (2006). Practical weed control in arable farming and outdoor vegetable cultivation without chemicals. Wageningen UR, Applied Plant Research: Lelystad, Netherlands.

Videos

Tilmor torsions via Michigan State University Extension

Hand torsion tool via The Market Gardener

Magic Cultivator as sold by Small Farm Works

In the Literature

Brown, B, and ER Gallandt. (2018). Evidence of synergy with 'stacked' intrarow cultivation tools. Weed Research 58(4):284-291