support

take string, and tie it up loosely on the stem of your main cola. attach the string to nearest structural surface, i.e. ceiling.

or you can use a broom stick or a yard stick or any kind of stick and affix it to the growing medium right next to the plant and use string or twisty ties on the stem.

or you can get a string or rope trellis and put it in your grow room (assuming you're growing indoors) horizontally which will create a grid that will stabilize all of your plants at once.

I would just get a long steak like thing and stick it in the soil close to the plant and loosely tie the two together. Or get a tomatocage