You could make a flowering fence with these if you were so inclined.
I got the initial idea for this instructable from this one called "bottle towers". However, mine are a little different in that they are free-standing and have a wicking system
Step 1: Supplies
About 6 empty plastic bottles, such as 2 liter soda bottles, or in this case Fiji water bottles. The only restraint is they have to be able to stack concentrically once their bottoms are removed.
hot knife and/or scissors
Step 2: Notch the Stake
Work a notch into the top of your stake if you can.
Tie the twine to your stake so it passes through the notch to help secure it there.
Step 3: Wrap Wrap Wrap
Wrap the twine around the stake as much as you care to. Just make sure the mouth of your empty bottle can still pass over the wrapped stake.
This will encourage water to follow the twine down the stake to the very bottom.
Step 4: Cut Doors Into Bottles
Cut an upside down U shaped flap in the sides of five of the bottles to create little doors.
You can do just one side, or all four sides of the bottle, it's up to you.
Step 5: Cut Off the Bottom
Cut off the bottom of all six bottles. You won't need the bottoms for this project, so you can toss or recycle those if you like.
Step 6: Pound Stake Into Ground
With a hammer or a big rock, pound the stake into the ground so it stands up straight by itself.
Step 7: Add Bottles
Slide one of the five bottles with doors cut out onto the stake, with the mouth pointing downwards.
Fill it with soil.
Open the doors up and drop a few seeds behind each door.
Add the next bottle in the same way, taking a moment to slide them together so the top of the second bottle fits concentrically and snugly into the open bottom of the previous bottle.
Repeat with the remaining four door bottles.
Step 8: Add the Watering Bottle on Top
This will be the container into which you will pour water to feed the system.
Fill it with water and watch the water cascade down through the successive bottles.
Step 9: Keep the Slugs Off of It
To keep the slugs away from the planter, I surrounded the bottom of it with ashes from the fireplace. I am told that slugs will not try to cross over the stuff.
Step 10: Wait About Two Weeks
I'm not really sure how often to water these. Because it's very hot right now and I put these in a bright sunny place with no shade, I've been filling the top bottle with water once a day. However, depending on the weather and shade, you may only want to water them once a week.
Depending on the seeds, in a few days you should be able to see the seeds sprouting through the clear plastic doors.
When they start to get leafy, open the doors a little to help them find their way out.