Isolate weeds when spraying herbicides. To improve your odds of killing only the plant you want to rid of, cut a two litre soda bottle in half over the weed you need to spray. Then direct your pump's spraying wand through the opening in the bottle and blast away. After the spray settles down, pick up the bottle and move on to your next target.

Try undiluted apple cider vinegar to kill off everything from poison ivy to crabgrass. Use it on a windless, sunny day and protect any nearby plants from accidental exposure.

Be weather- wise. Herbicides work best when temperature are mild- 21 to 27 degree celsius and soil is moist. Don't apply spray before a rain, which will wash them away.