Learning Objectives:

Understanding the moisture-wicking ability of wool-containing yarn
The important of reusing materials
What plants need to survive
Space and money-saving methods for gardening

Target Audience:

Younger children - Approx. Grades 3-5

Standard for Technological Literacy:

Standard 15 - Students will develop an understanding of and be able to select and use agricultural and related biotechnologies

Creating this fun self-watering pot is a great opportunity for you and your kids or students to discuss the benefits of finding cost and space saving methods of gardening indoors when faced with not having access to outdoor land suitable for growing plants. Additionally, this project brings up the topic of reusing. It is important to explain how the concepts of reducing, reusing, and reducing (specifically reusing in this case) are so important to humanity's survival in the future.

Supplies

1 Plastic Water Bottle (with cap)
Wool Yarn (at least 10 inches long)
Scissors
Knife
Soil and Plant

Cost Estimation: 0$ - 15$

Many of these supplies are common household objects, but you may need to purchase the yarn, plant and soil if you don't already have access to these.

Step 1: Cutting Your Pot

First, choose where on your water bottle to cut it open. Make sure to select a spot on where the diameter of the bottle is widest, if you don't the soil-holding portion of the bottle will be small enough to fall through to the bottom of the bottle. Next, you're going to cut the bottle all the way through at this mark with your scissors or knife. I found it easier to make the cut with the knife and then clean up the edge with scissors.

Step 2: Cutting the Cap

Next, you will be cutting a hole in the center of the water bottle cap just wide enough for your yarn to fit through. For this, I suggest securely holding the cap down while testing and pressing down gently with the tip of the knife. The knife should gradually create an indent and then a slowly widening hole in the cap. Make sure to watch your fingers!

Step 3: Inserting the String

Next, take your piece of yarn (about 10 inches long) and pull it through the hole in the cap. If you find this difficult, you can widen the hole as needed or even thread it through with a bobby pin. On each side of the cap, you're going to want about equal portions of the yarn.

The reason you have to use wool yarn for this step is because of the absorbent properties of wool. Typical wool is able to absorb up to 30% it's own weight in water, and by selecting a yarn that contains wool you are ensuring that the yarn will absorb the water and it will in turn be absorbed by the soil in the upper pot in order to maintain equilibrium in terms of moisture.

Step 4: Adding Soil and Your Plant

Next, fill up the top part of your pot with your chosen soil and add your plant! For mine, I have chosen a basic potting soil along with a small spider plant that I had been rooting in water beforehand.

Step 5: Adding Water

Fill the bottom part of the pot with water, but make sure the water level stays below the cap where the yarn is coming from. If your water reaches this level, the soil will become too moist. One the other hand, make sure there is enough water to submerge enough of the yarn.