Garlic is not very competitive, so good weed control is critical. Mulch will control weeds and conserve moisture. If the mulch is removed, cultivation will likely be needed. Cultivation should be shallow so as not to damage roots.
Stale Seedbed
The following herbicides are nonselective and are used to control weeds that are present in a field prior to planting or before the crop emerges, which is especially useful for the Stale Seedbed Technique (see the Weed Management section for more information).
- glyphosate (Roundup Power Max): PHI 14d, REI 4h, Group 9.
- paraquat (Gramoxone SL 2.0*): PHI 60d, REI 48h, Group 22. May be fatal if swallowed or inhaled. *Restricted use: Applicators must complete an EPA-approved paraquat training every 3 years: https://www.epa.gov/pesticide-worker-safety/paraquat-dichloride-training-certified-applicators.
- pelargonic acid (Scythe): PHI 1d, REI 12h, Group 0.
Preemergent Herbicides (before weeds germinate)
HRAC Group 0:
bensulide (Prefar 4E): 5 to 6 qt/A; REI 12h. 1 application per year. Apply before planting or after planting before crop has emerged. Grass control only.
HRAC Group 3:
pendimethalin (Prowl H2O): 1.5 to 3.2 pt/A; PHI 45d, REI 24h. Do not exceed 3.2 pt/A. Apply after planting but before crop emergence, after crop emergence when garlic is in the 1- to 5-true leaf stage, or at both timings. Contact with crop will cause damage.
HRAC Group 14:
flumioxazin (Chateau EZ): 1.5 to 6 fl oz/A; REI 12h. 1 application per year. Apply within 3 days of planting.
HRAC Group 15:
dimethenamid (Outlook): 7 to 21 fl oz/A; PHI 30d, REI 12h. Do not exceed 21 fl oz/A per year. See label for single vs. split application rates. Apply to garlic that has 2 fully expanded true leaves.
s-metolachlor (Dual Magnum): PHI 60d, REI 24h. MA, ME, and NH only. Restricted label: Make sure the label for your state is available for download before using this product. Full label instructions are supplied to growers who apply through the website www.syngenta-us.com/labels/indemnified-label-login and agree to a waiver of liability. Main target weeds for this registration are galinsoga and yellow nutsedge.
Pre- and Postemergent Herbicides
HRAC Group 27:
bicyclopyrone (Optogen): 2.6 to 3.5 fl oz/A; PHI 45d, REI 24h. 1 application per year. Apply before transplanting or to row middles after planting. Contact with crop will cause damage.
Postemergent Herbicides (after weeds germinate)
HRAC Group 0:
pelargonic acid (Scythe): 3% to 10% solution; PHI 1d, REI 12h. Apply for vegetative burndown during site preparation, prior to crop emergence from soil, as a directed and shielded spray during crop growth, or as a harvest aid and dessicant. Contact with crop will cause damage.
HRAC Group 1:
clethodim (Select Max): 9 to 32 fl oz/A; PHI 45d, REI 24h. Do not exceed 64 fl oz/A per year. Apply to actively growing grasses.
fluazifop (Fusilade DX): 6 to 24 fl oz/A; PHI 45d, REI 12h. Do not exceed 48 fl oz/A per year. Apply to actively growing grasses.
sethoxydim (Poast): 0.5 to 1.5 pt/A; PHI 30d, REI 12h. Do not exceed 4.5 pt/A per year. Apply to actively growing grasses. BASF has stopped production and will discontinue the registration at the end of 2027.
HRAC Group 9:
glyphosate (Roundup PowerMax): 10 oz to 3.1 qt/A; PHI 14d, REI 4h. Do not exceed 5 qt/A per year. Apply during fallow intervals, prior to planting, at planting, before crop has emerged, or to row middles with a hooded or shielded sprayer or wiper applicator. Spray contact can cause crop death. Spray additive recommendation varies with formulation—see label.
HRAC Group 14:
carfentrazone (Aim EC): 0.5 to 2 fl oz/A; REI 12h. Do not exceed 6.1 fl oz/A per season. Apply as a preplant burndown no later than 30 days before planting by seed, or with a hooded sprayer to row middles. Contact with crop will cause damage.
oxyfluorfen (Goal 2 XL): 2 to 4 fl oz/A; PHI 60d, REI 48h. Not for use on garlic grown for seed. Apply to garlic that has at least 3 fully developed true leaves. Do not exceed 32 fl oz/A per year. Temporary chlorotic leaf banding may occur but should not reduce yield. Do not use spray additives.
HRAC Group 22:
paraquat (Gramoxone SL 3.0*): 1.7 to 2.7 pt/A; PHI 60d, REI 48h. 1 application per year. Apply before crop has emerged as a broadcast application. May be fatal if swallowed or inhaled. *Restricted use: Applicators must complete an EPA-approved paraquat training every 3 years: https://www.epa.gov/pesticide-worker-safety/paraquat-dichloride-training-certified-applicators.
HRAC Group 24:
bromoxynil (Broclean): 1.5 to 2 pt/A; PHI 112d, REI 12h. Apply to garlic after emergence, before it is 12” tall.