I found 2 methods on-line for using soda bottles as seed starting containers and I decided to give both methods a try in a (semi-controlled) test to see which worked the best. The 2 sites I used were: seattlesundries.com. and homeguides.sfgate.com.
My list of items needed was short:
An empty bottle
A drill (or a hammer and nail)
Wood (or something to protect your table)
Hole punch (optional)
For our 1st project....
Using a drill (or a hammer and nail) make a hole in the lid large enough to thread the string through. This is most easily accomplished with the cap turned upside down. A piece of wood protects the table underneath
Thread both ends of the string through the upside down cap and tie a bow in the top of the string.
Using a sharp knife (and a pair of gloves for safety) cut off the top portion of the bottle.
Screw the cap on bottle
If you have a hole punch you can make a hole about an inch below the top of the "base" of the planter. This will help you add water easily later on. Place the top half into the bottom (base) of the bottle.
Add soil and plant your seeds. The string will wick up water to keep the soil moist, but if the top dries out you will want to add a little water from above.
For our 2nd project....
Use your knife to cut the top off of the bottle
Use the drill (and the wood) to drill drainage holes in the bottom of the base.
Use a pair of scissors (or your sharp knife) to make a couple of 1 inch long cuts up the side of the top portion of your bottle.
Fill the base with soil and plant your seeds. Screw the cap on the bottle. I placed the top portion inside the bottom half. The cuts made this rather easy. You may want to place the top portion outside the base, but personally, I found this a little difficult, and the small gap in the cuts I made would have allowed moisture to escape.
I'm anxious to see which of these methods germinates my seeds most quickly, as well as how effective my self-watering pot is. I'll keep you posted.
Be well, and Happy Gardening.