Block Weeds Organically Using Opaque Plastic Mulch Films:
- Block sunlight and prevent weed seed germination without chemicals
- Eliminate annual and most perennial weed competition
- Used for more than 30 years in commercial agriculture
Opaque plastics block the sunlight that causes most weeds to germinate. Plastic mulch is extremely effective in controlling weeds. About the only plant that can grow under opaque mulches is nutsedge which stores extensive energy in its underground "nuts," and can germinate in darkness.
Here is a quote from Rutgers Univeristy:
Weed Control for Crops Commonly Grown on Plastic Mulch Plastic mulch, usually used with trickle irrigation, has many horticultural benefits for summer vegetable crops, and black plastic controls most annual weeds. Mulch does not solve all the weed problems in the field, and creates new challenges for the grower. Yellow nutsedge can poke through black plastic mulch. Yellow nutsedge pokes through black plastic mulch and thrives under mulch and trickle irrigation. Clear plastic is used to obtain the greatest advantage in earliness, but weed control under clear plastic can be difficult and challenging. Although black plastic controls many weeds, yellow nutsedge can pierce black plastic and thrives in the mulched and trickle irrigated environment. Nutsedge pokes through black plastic in the absence of light and day/night temperature changes which signal the weed to stop growing upward and to grow leaves. Fields with heavy nutsedge infestations should be avoided, if possible, when choosing fields for crops to be grown on plastic mulch.