how to prevention of cracks from vegetation?

Answer 1

POUR TABLE SALT ON THE YOUNG SPROUTS,THUS KILLING THE WEED, BEFORE THEY GROW AND ENLARGE/EXPAND THE CRACKS WIDE OPEN/APART!!!

Answer 2

Buy weed-killer, weed-out etc from any garden center. Destory and eliminate roots. Drain water away from walls with sloping ground if vegetation is climbing into the walls. Better yet pave a foot around fondation with cement blocks, bricks etc. Lay the bricks or stones over crushed stone, covered with plastic or the black tarp available from garden centre for this purpose.