Organic Weed Control

 Crabapple LandscapExperts have noted the demand for alternatives to toxic chemicals to control weeds is rising. Consider two modes of operation: mechanical and common household chemicals. 

Mechanical Methods Organic Weed Control

Mulch

Apply mulch before the weeds get started

Organic mulches

Wood chips, pine straw, compost

Layers of newspaper

Temporary area: cover with thick opaque plastic for 3 months

Solarization

Cover soil with clear plastic (painters plastic) to steam-cook weeds

Smooth and level soil, 

Water thoroughly

Causes heat build-up under plastic, and weeds steam cook

Hand pulling/weeding by hand

Slow and steady wins the race

Remove all seed heads (trash, not compost)

Screw driver

Cobra head

Pronged weeding tools

Hoeing

Stand-up

Scuffle or Oscillating Hoe

Warren Hoe

  

Flaming or Weed Torch

xNot recommended

xBurns off tops but often roots are still alive

xDangerous, burning permit required, not within 50 feet of structures

xYouTube video where house caught fire

xHeavy

xTime-consuming

√More economical for large areas

xNeed burning training  

xHave hose and shovels ready

Common Home Chemicals Used for Organic Weed Control

Boiling water

Entirely organic with no lingering effects

Inexpensive

Simple

Boiling water in kettle or coffee carafe with pour spout

Pour slow stream directly on crown of plant

4 hours later look like cooked vegetables

Wear long pants and closed-toe shoes to avoid burning if spilt

May need to repeat if entire taproot has not been scalded

Vinegar
Acetic acid

Full-strength white table vinegar

Spray in small sprayer

Add a few drops of liquid dish soap as a wetting agent

Quick-acting, Non-selective

Can change pH of soil

Later, weeds may re-grow from roots

Some weeds are not susceptible to vinegar (waxy coating, storage roots)

Salt

High salinity causes reverse osmosis

Slow but effective

Affects soil, runoff too

Can reverse by flooding with water several times

“Sow the fields with salt” punishment for defeated cities b/c prevents regrowth of plants. Also a symbolic purification of conquered cities

Rubbing Alcohol

Draws water out of cells

Non-selective and will kill your good plants too

Bleach

Sodium hypocholorite, breaks down to water and salt

Harsher for environment than vinegar

Corn Gluten Meal

Biproduct of corn patented by Iowa State U in 1991

Pre-emergent Seeds sprout then corn gluten meal inhibits roots from growing and young seeds dehydrate

Expensive

Narrow window of opportunity: timing just as weed seeds are germinating in early spring

Doubles as 10% Nitrogen organic lawn fertilizer

Common Recipe for Organic Weed-Killing Mixture

1 Quart vinegar

1 Cup salt

Few drops liquid dish soap

Hand sprayer

Spray foliage, works best in sun