Greenhouses are great for growing plants because they provide a controlled environment, they retain heat when it's cold and they protect the plants from invaders such as pests, bugs or diseases. It's an ideal way to grow a plant, especially when it gets cold during the winter. Even better, you can make a miniature greenhouse in your own home from common household products and be growing your new favorite plant in no time.
Strip the plastic bottle. Remove the cap and recycle it, then remove any labels or other packaging on the bottle. It needs to be bare.
Clean the bottle. It's best to use a heavy duty cleaner such as bleach to make sure that your soon-to-be greenhouse is as clean an environment as it can be. Leave it upside down in the sink until it dries.
Mark where you want to cut. Look for two things in finding where to cut. You want the end product to be as tall as possible, so you should be cutting near the bottom of the bottle, but you also want the greenhouse to be as wide as possible, so make sure you're cutting at the bottle's widest point, too. Mark the spot with the permanent marker.
Use a scissors or knife to cut the bottom of the bottle off. If you can't start cutting with your scissors alone along the line, use a knife to puncture the bottle, and then put the scissors through the hole and start cutting.
Ready your greenhouse. Take the soil, the seed or plant you plan on using and whatever fertilizer you like and put it in the pot. Depending on the size of the pot, the greenhouse can either completely encase the pot or it can be stuck into the soil to cover the plant---both ways are fine.