SetBounds worked for me but these two ways
PHP Code:
ents[i] SetBounds(100, 1000);
ents[i] SetContents(1);
are making the exact same thing, just for the first one not necessary to spawn a triggerPHP Code:
level.plants[0].trigger = Spawn("trigger_radius", ents[i].origin, 0, 100, 1000);
level.plants[0].trigger SetContents(1);