Hydroponic Soda Bottle System

Hydroponics is growing plants without dirt. Plants are grown with their roots in an inert medium. The medium can be perlite, rockwool, coconut husk, or rocks. They key is you keep the roots exposed to a nutrient rich water solution.

Hydroponic systems come in many didn't shapes and sizes. Today I'm going to demonstrate how to make a simple system using mostly things you have around the house. I did this with my 7 year old daughter on a recent snow day so it's also a great indoor winter activity.

visit captainhydroponics.com for more hydroponic system ideas or to just learn more about it.

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Step 1: Gather Supplies

Before you start any project, it's smart to gather everything you need to avoid any mid-project surprises. Below is what you need today. Most items should already be in your house and the last 3 can be picked up at a local Home Depot.

Empty 2 liter soda bottle
An old sock (you can use any cotton material)
Black marker
Small mixing bowl
Cling wrap
Perlite (available at your local Home Depot or Amazon)
Peat Moss (available at your local Home Depot or Amazon)
Seed of your choice (I'm using lettuce in this example)

Step 2: Prepare the Soda Bottle

Rinse your 2 liter soda bottle, draw a black line ~ in the middle of the bottle, and cut the bottle in two.

Step 3: Create the Wick

Stick the sock halfway through the soda bottle top. You may need to cut the sock down but use a piece large enough to fully block the hole so your medium doesn’t fall into the water reservoir.

Step 4: Mix the Medium

Mix the perlite and peat moss in a 1:1 ratio in your mixing bowl. You only need about 1 cup of each to fill your 2 liter but if you mix extra like I did you can save it for your next hydroponic DIY project. Tip: the reason I used the Miracle Grow products is that they already have the required nutrients for at least 3 months of growing so you don’t need to worry about adding fertilizer to your water.

Step 5: Fill Reservoir

Fill the bottom half of the 2 litter with water.

Step 6: Attach Grow Tray

Place the top half of the bottle upside down into the water. The wick should extend at least 1 inch into the water. You also want to ensure the sock is completely blocking the hole.

Step 7: Fill Growing Tray With Medium

Fill your new planter with your perlite/peat moss mix. If some dirt falls into the water don’t worry. Just dump your water out and refill.

Fun learning tip: At this point my daughter and I watched the wicking action. Here’s how much water was absorbed by the sock and medium in about 10 minutes.

Step 8: Water the Medium

Moisten your medium by slowly pouring 1 cup of water over the top of the medium.

Step 9: Sow the Seeds

Tuck several seeds just under the top layer of medium. I would suggest about 1/8 of an inch.

I used lettuce in this example but another great idea is Basil or any other herb that your family likes and uses.

Step 10: Create a Mini Greenhouse

Wrap the top of your bottle in cling wrap to help the germination process.

Step 11: Store in a Warm Place

Seeds like it a little bit warmer than room temperature and usually don’t need light so I put our bottle in our utility closet with our heating system. It kept our DIY hydroponic system at about 80 degrees.

Step 12: Move to a Natural Light Source

Once the seeds sprout up about an inch, place the 2 liter on a window sill for continued growth. This took about 3 days for my lettuce seeds.

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    14 Discussions


    5 months ago

    This is fun but it takes a little while to grow but still fun!!!!!!!!!

    2 replies

    Question 6 months ago

    is it hard to make


    Question 1 year ago on Step 5

    Do you recommend tap water, distilled water, or well water? Does it really matter?

    Can a liquid fertilizer (such as 'Ultra Thrive') be added to the water?

    Jane Ward

    1 year ago on Step 12

    Really grand idea, thank you. Would it be OK if I shared this on the zero waste blog? Jane


    3 years ago

    I'm kinda new to the whole hydroponics thing, but isn't this self watering and not hydroponics? I mean, because of the peat moss? If it were, say, perlite an vermiculite I would see the connection better, but you''re using dirt....

    1 reply

    Reply 3 years ago

    I believe this is a SIP - Sub-Irrigated-Planter


    3 years ago

    How often should I water the medium? And do I need to change the water reservoir often? I made three of these for a school project! They are awesome and thank you so much!