if i repot a plant/clone into a bigger pot, and i bury the stem up to the closest node, will the roots grow UPWARD into that dirt or only out and down from where they already are????? I have a few clones that i wanna put into 3 liters and flower but they have about 3-4" of bare stem i wanna cover, but b/c of only 3-liters of soil space i dont wanna waste any dirt if roots arent gonna reach it...