How do you make "cement or concrete filled containers to hold flowers outside on tables for weddings as decor.

I need to make little bases for holding flower and balloon arrangements outside as decorations for tables. I need something fairly heavy so they don't fall over. Can I use cement or concrete of some kind and which does the best job. I would like to fill little flower pots with the "cement" and then put small arrangements of balloons and flowers inside. These will be used for several occasions. What are your suggestions?

How do you make "cement or concrete filled containers to hold flowers outside on tables for weddings as decor.
Several ways to go here, depending on exactly what you want. You could fill the little containers with gravel(building supply stores sell bags of it) if it won't be seen through the containers. You can also buy at craft stores those little glass stones, same purpose but prettier looking and more expensive. You can then stick the flowers in either of those. If you want to weight a container with something solid, plaster of Paris is what you want. It will make a solid lump in the bottom, decide how much to put in to hold up whatever it is. If you put some plastic wrap in the pots first, you should be able to pull the lump of plaster out after if you want.
Reply:Since you will be reusing the pots, go the cement route. Try this, put a skinny plastic or glass cup in the center (maybe a lab supply store will have this) and then pour your cement around it - or just jam it in the center after you pour the cement! This way, you can have a center channel to place the flower stems in. You can also put an "eye hook" into the cement so you have something to tie the balloons too!