You will need: an empty non-colored 2-liter soda bottle, a power rotary tool (aka a "Dremel"), X-ACTO knife / box cutters. A) Rinse out the soda bottle, and then remove the label. B) Use the rotary tool to cut an incision in the base of the bottle from a vertical "valley" to the underside of the bottle (see pic #2). Do not try to use scissors, a chef knife, or the X-ACTO knife / box cutters; the plastic in the base is extremely strong and you may injure yourself if you try to use a lesser tool. C) Move to the adjoining "valley" and make the same incision. You are trying to cut a "foot" loose from the soda bottle (see pic #3). Due to the thickness of the plastic in the base of the bottle, you may not be able to make the incisions all the way to the center of the underside of the bottle. In pic #4, you will see that I had to stop several mm from the center, resulting in the removal of a pentagonal (because my bottle had 5 "feet") piece of plastic from the center of the underside. D) Repeat step C until all the "feet" are cut free. E) Bend the feet back and splay them out like an upright octopus (see pic #5). Your Critter Shield is complete.
Step 2: Apply the Critter Shield
Place your new Critter Shield around your tender sunflower seedling (you can apply the CS before the seed sprouts for maximum protection). As shown in pic #1, put large rocks or bricks onto the feet of the CS to anchor it. This will prevent strong winds, rainstorms, and smart critters from knocking over the CS. The CS allows sunlight in to your plant, and will trap heat and moisture. However, you will most likely need to water your sunflower by hand to ensure steady growth. When your sunflower reaches the top of your CS, use the X-ACTO knife / box cutters to cut the top off the bottle (see pic #2). There is no need to discard the CS; it should continue to repel birds and rodents even with the top removed, and the girth of the CS should be sufficient to accommodate all future growth.