วีดีโอ

I believe and I'm no professional but... I believe it's because the crops have already established roots I.e grass or sod must be mature wouldn't want to use a preemergent if it's not at least 2 years old. The pre emergent stops seeds from forming roots.

Pre emergent herbicide only kills growing weeds not any seed that hasn't started the growth cycle.. It should only be applied upto 48 hrs after planting max otherwise you kill your newly planted seed.

Basically magic. Preemergant herbicides will prevent some crops from growing but not others, pumpkins are one that I know that doesn't survive.

- The herbicide is very effective in entering the plant but it cannot leave the plant and so it builds up and kills the plant - It is very specific to weeds and broad leaved plants rather than grasses and other similar vegetation - Hope this helps, please reply me if it does!

@@tulipcheong1179 it does. Thank you very much

@@BrandondoodGames Hope you don't mind me asking, but are you a biologu student or just interested in this field..?

@@tulipcheong1179 just interested. Did a full lawn reno and researching lots of things to keep the new lawn happy

@@BrandondoodGames Ah... I am a biology student and looking forward to take IGCSE exams next year.... Do you want to be friends?

- The herbicide is very effective in entering the plant but it cannot leave the plant and so it builds up and kills the plant - It is very specific to weeds and broad leaved plants rather than grasses and other similar vegetation - Hope this helps, please reply me if it does!

@@tulipcheong1179 Thanks for the reply. Question please: does the herbicide prevent weed seed germination or allow germination then kills the weed?

@@Mote78 "*The herbicide/weedkillers (normally contain the chemical 2,4-D as an active ingredient) kill weeds and broad-leaved plants in either form (either in seed form, seedling form, or adult form) by entering and building up inside the plant; it also increases their rate of respiration so much so that all food reserves are used up and the weed dies. So basically it kills the weeds (so it stops germinating in seed form as the embryo inside it has already been killed, or if the weeds have already sprouted the weeds will be killed as their cells stop functioning and die)*"

Sounds like you have some serious weeds to manage. If you need any help finding a retailer, please let us know.