Hydroponics for Kids: Build a 2 Liter Bottle Garden

Ed Wike
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Hydroponic Gardens: A Great Experiment For Kids

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Young kids love growing their own plants. The prospect of watching a seed or small plant grow into a mature plant with a bounty of fresh fruit or veggies is captivating to children who are just beginning to understand and appreciate the natural world. The excitement is amplified when the plants produce food that can be eaten. Children feel a real sense of accomplishment and connect more strongly to nature as they watch and help to nurture plants.

What Your Child Will Learn

In this process, they will learn that food can come from anywhere. These gardens are sustainable and self-contained. They do not contribute extra plastic waste into the earth and benefit both people and the planet. Depending on your child’s age, creativity, and the variety of greens they choose to grow, they can experience a variety of learning outcomes.

Using these gardens can help your child learn how to grow their own food and start a hobby of gardening. These backyard gardens also help your child start a lifelong hobby of gardening. They will also help your child learn that it is possible to grow food without all the chemicals and pesticides. Finally, they will be able to take a product that most would discard and turn it into a usable garden.

Gardening with your child can also help you teach them about environmental awareness, growing their own food, and how to become self-sufficient.

This garden will also provide an opportunity for learning about the appropriate use of electricity and air conditioning. While it is likely that it is going to get hot in the summer, in these climates, having an option for your plants to get air conditioning from a window AC unit is nice for ensuring that your plants have a longer growing season.

You should also encourage your child to use the second hand stores and watch for a future unit that they can disassemble and use for their garden.

The Materials You’ll Need

Materials Breakdown

This hydroponic system is very easy to set up and is inexpensive.

Small clay pots are generally used for hydroponic systems, however in this system you could also use small plastic cups or any small container that is lightweight and will fit in a 2 liter bottle without a problem.

The next thing you need to decide is what kind of plant you plan to grow. Most any plant will do, although those that have very specific light and temperature requirements should be avoided. This hydroponic set up is best suited to leafy vegetables, herbs, or small flowering plants.

The best vegetables to grow in your plastic bottle garden include leaf lettuce, basil, and chives. Other good herbs are mint, parsley, and any type of flower that you are looking to grow.

The seeds or plants you choose are the second thing you will need to gather for this hydroponic vegetable garden.

The third thing you will need is a clear plastic bottle. One that is in the shape of a 2 liter bottle is the best choice, however just about any size clear plastic bottle will work for this project.

Fill the bottle with water and allow the excess to turn into a neck at the top of the bottle. Make sure it is not too big to fit over the rim of the bottle.

Step 1: Prepare 2 Liter Bottle

There are two holes that need to be cut out: the first on the bottom of the bottle where the opening is, and the second on the side, near the top, where the water will drain out.

Make sure to make the holes a bit on the smaller side and to make the first hole smaller than the second, to make it easier for the water to drain.

The simplest way to cut the holes out is with scissors. You'll want to make sure that you cut slightly inside the bottle, as you don't want the edges of the bottle poking out.

Now you're ready to plant your seeds.

Step 2: Plant Your Seeds

You'll want to fill your bottle about ¼ of the way up with a little bit of dirt.

Next, take the seeds you want to plant and put them at the bottom of the bottle.

Carefully fill in the rest of the dirt.

You can also plant any flowers you want.

If you think you'll be adding extra bottles, you can space them out.

You'll just want to make sure they have enough room so that when they grow, they don't touch.

If the bottle you use has a very small opening, you can cut the top of it off, and make the filling process a lot easier.

Step 2: Prepare The Water

What you'll need:

5 cups of rain water

5 cups of de-chlorinated water

The 2L Bottle

All ingredients should be mixed into the water with the exception of the bottle itself. Only the bottle needs to be sterilized. Complete sterilization is required, otherwise mold and bacteria will start to grow.

Take the bottle and soak it in a solution of 1 part bleach and 5 parts water. Keep the bottle in this solution for at least 15 minutes. You should then rinse the bottle in water that is at least 99 degrees Fahrenheit. Finally, you need to dry the bottle by shaking it out or by leaving it out to be air dried.

The container that you just made is now ready to be used for the plants and the microbes. The jug of ingredients should be stored in your fridge and it should be used within 1 week. The jug can be used to make another solution after that point … but you should never put plant cutting into the old solution that was used to sterilize the bottle in the first place.

Step 3: Add Wick and Growing Media

Take your clay pellets and fill the bottom of the 2 Liter Bottle using a measuring cup. You should fill the bottom 1/3 of the bottle.

Add the clay pellets until the bottom of the 2 Liter Bottle is nearly full.

Place the screen over the 2 Liter Bottle and place the plant seeds between the planting holes.

Fill the rest of the planting holes with more clay pellets.

Place ONE small drop of water on the clay pellets to make them wet.

Cover the top of the 2 Liter Bottle with the plastic part.

Poke some holes in the top of the plastic to allow for water to come in.

Sandwich the plastic and the top of the 2 Liter Bottle with a zip tie.

Poke 4 discs into the sand. These discs allow the wick to reach the clay pellets.

Step 4: Plant Your Seeds!

{1}. Gently remove the lid from the bottle.
{2}. Pour your seeds into the bottle. You can put as many seeds as will fit in the space. If the dressing cap fits tightly, you can't put as many in it as the other bottles.
{3}. Add water to the bottle, making sure the cap is still loose (as you don't want it to flood).
{4}. Add the lid tightly.
{5}. Shake the bottle periodically to help ensure even germination.
{6}. Wait, wait, wait.

Finished Product

The 2 liter bottle hydroponics garden is a very attractive science / educational project for kids. Every stage in the process of growing and watering plants comes full circle with this project. It is also a great way to reinforce science and math skills with the help of your kids.

Here is what you need to begin:

Clear 2 Litre Bottle (Since glass is a solid substance, you can place this in your garden without worrying about it tipping over.)

16 oz. of colored water (blue, red, yellow, etc.) (The colors represent the different nutrients required of plant life.)

Rubbing alcohol (You need only a drop.)

Water (Pure and unfiltered is best.)

Aqua globes (The liquid mold that you place inside the water beads.)

Activated Charcoal (This absorbs the light around your plants, which allows photosynthesis to take place.)

Potting Soil (Most are enriched with nutrients to help the growth of your plants.)

Plants

Step 1:

Cut the bottom off the 2 liter bottle, and fill it with soil.

Step 2:

Add aqua globes and water.

Step 3:

Start with one color water, and fill up to the desired amount with another color.

Step 4:

Maintenance

By this point in my hydroponic journey, I had become somewhat of a water snob. The perfect weight, clearness, and pH are now among my major concerns.

However, I once again had to take the road less traveled in order to teach my gardening classes. As it turns out, a great deal of patience is required in order to help the less experienced grow healthy and happy plants. Their most frequent concern is simple: what do I do now?

My Hydroponic Gardening for Kids project at the Susan W. Vigon Cultural Center was, as always, a great success. I think it's safe to say that the kids learned a lot, and got a great deal of enjoyment out of it, as well.

The best way I could think to help them was to obey nature's golden rule: Give it adequate water and grow it in a place that gets adequate sunlight. With that in mind, let's build some gardens …

Plant Details

Container: 2 liter bottle with the top cut off and enough space left to accommodate a plant.

Vegetable: Lemon Balm (used fresh or dried), Pink and Red Cherry Tomatoes, Red Basil.

Soil: Compost is recommended, but for kids we used coconut fiber (coir) from whole coconut with the husk and sawdust and other trimmings mixed in for a more pleasing texture. This looks similar to soil and can be reused to grow more plants with minimal cleaning.

Spray Bottle: Water is added at a ratio of 1 part water to 1 part water from the spray bottle. We used a 20:1 ratio: 1/4 cup water at 20:1 from spray bottle.

Light: Given the height of the bottle a fluorescent light with a fluorescent bulb was positioned over the bottle. You can substitute a lamp with a shade to further protect the light for the plants from the heat of the bulb.

Food: Liquid seaweed was watered into the water when it was added to the bottle. The seaweed comes in a liquid form in a spray bottle.

Germination

Remove the cap and the label from the bottle and peel away the label from the cut edge.

Next, rinse the cap and label thoroughly to remove any remaining glue residue.

Fill the bottle with potting mix to within 1" of the top and firm the potting mix down by firmly squeezing the bottle.

Place the cap on the bottle, ensuring the opening of the bottle is well below the surface of the potting mix. This will help to improve oxygen levels.

Using the scissors, carefully remove the plastic sleeve from around the cap and any staples leaving the cap exposed.

Fold the sleeve to reduce it by half or to just one staple.

Place the bottle on the seedling heat mat and ensure that the cap is correctly positioned on the bottle.

Lighting

T5 fluorescents are great because they're energy efficient and produce plenty of light.

A typical T5 fixture, like the bulbs, last about 10,000 hours.

These fixtures can be purchased in a 4” size, which will work for a 6 liter container. A good place to purchase them is at Home Depot or Lowes.

You'll need to mount the fixture to the lid of the bucket, so that the light radiates directly down onto the plants.

The plants don't get enough energy from light to grow horizontally, so they grow upward toward the light. Mounting the fixture to the lid helps the light to shine directly down onto the plants.

The light should be mounted in the center of the lid, equidistant from the edges. This way, light will be reaching the plants from every side.

If you want to be able to adjust the height of the light, you can mount it to a board, which can sit on top of or be secured to the rim of the bucket.

T5 bulbs should be purchased based on the size of the plant, the height of the plants will be, and the amount of space you have available in your bucket to allow for growth. Be sure to get one T5 bulb for every 4" of plant height.

Watering

You will get the best results if you use nutrient-extracting plant food in place of regular water. However, if you're up to it, you can substitute 30% of the water with plain drinking water and 70% with nutrient-extracting plant food. But why take the automatic route? With real water, you can monitor the PH and nutrient levels of your water to ensure quality growth.

Your 2-liter bottle should be watered daily. When the top of the water line begins to fade into the soil, then it's time to refill. Also, because of the environment inside the bottle, you should change a quarter to a third of the water about every two to four weeks.

Harvesting

Cut the tomato from the vine and put it into the refridgerator to slow the ripening. Then mark the date you started picking when you write the date on the label.

Don't let your tomato go too long in the fridge however. Tomatoes can easily become moldy, so keep an eye on them. But storing them in the refrigerator will slow down how quickly they ripen and will make the tomatoes taste more flavorful once you decide to eat them.