picture of Knawel
was asked to send picture but somehow edit could not go thru. I asked if the Knawel which are relatively young and easy to pul out but is everywhere can be scraped out with a tool from Beets Industry that just goes under the root on the ground scraping it out but becomes mixed with soil and knawel is difficult to isolate from the soil. It seems that if there is no flower from Knawel that I can see with my naked eye, it would be OK to scrape them and leave on ground as opposed to pulling them out from their taproots as there is no chance to spread if there are no flowers as log as the tap root and plant is completely pulled out? Of course where it is mingled with other weeds, I Have to pul out the other weeds that has flowers.
Knawel is an annual that will sprout from seed in warm or cool weather. (In a warm winter, it will flourish all winter.) You will not be able to see the flowers; they are too inconspicuous. However, it flowers from may to October, so during that time period you will not want to pull and leave plants on the surface of the soil because of the danger of the plants having seeds and reseeding.
Yes, you can use a hoe-like tool to kill immature seedlings. If they are immature and have no seeds, then, yes, you can leave them on the surface.
There is probably already a build up of seeds in the soil (called a seed bank.) Even if you prevent any plants from going to seed, these old seeds in the soil can germinate for years. The problem with hand pulling and hoeing is that it disturbs the soil and turns up buried seeds, which can then germinate.
We recommend that you prevent germination altogether. Cover the bare soil in the beds with 3-4 layers of newspaper, overlapping. Then top that with 1-2" of mulch. When the newspapers and mulch decompose, repeat. Do this for the next few years at least.