Upcycled Hydroponics Planter
What Will You Learn?
Learn how to make a hydroponic planter with a wicking system that allows plants to use less energy to get the nutrients that they need.
Prepare the Planter
First, we need to create our planter. To do that we’ll modify a clean water bottle.
Start by measuring about 2 1/2 inches from the top of the bottle. Mark it. Use your scissors to cut the top from the bottle. The bottom of the bottle will be a reservoir for your nutrient solution. The top will hold the growing media and seeds.
Next, use the awl (or a Phillips head screwdriver) to pierce a hole in the center of the cap.
Make the Wick
Now we need to make a wick for our planter. The easiest thing to do is to upcycle an old, unmatched washed cotton sock. If you don’t have one an old towel or piece of felt will work. Use a sock made of natural fiber, as polyesters and nylons won’t wick your nutrient solution well.
Cut a strip from the sock that is between 1/2″ to 1″ wide. It doesn’t have to be perfectly straight. Do not use the ribbed portion of the sock. The length should be approximately as long as the bottom section of the bottle.
Tie a knot in one end of the strip of fabric, about 2 inches from the end. Leave a tail roughly the length of the bottle on the other side.
Push the unknotted end through the hole you made in the cap so that the knot is on the inside of the cap. If needed, widen the hole to allow the strip to pass through, but take care not to widen it so much that the fabric falls out of the cap.
Place the cap back onto the neck of the water bottle.
Prepare the Hydroponic Reservoir
Place some gravel in the bottom of the water bottle. This will help keep your planter from falling over, especially if you have pets. Small rocks or glass marbles also work. Make sure you clean and rinse the gravel well before adding it to the water bottle.
Mix your nutrient solution as described on the bottle. Usually, hydroponic nutrient solution will come as a liquid concentrate. One solution is a base, with potassium, phosphorous, and nitrogen needed by all plants. You then supplement with a second solution for the type of plant you are growing — flowers, vegetables, etc. Often you will make a dilute solution to start with and increase the concentration of nutrients as the plant grows.
Add the solution to the bottom of the bottle, your reservoir. Do not fill it all the way. Invert the top of the bottle and place it on the reservoir, so that the wick hangs down into the nutrient solution. You may need to trim your wick.
Tip: Depending on your water and what you plan to grow, you may need to adjust the pH of your nutrient solution.
Prepare your hydroponics matrix
Fill the inverted top of the bottle with growing media, leaving some space between the top of the media and the rim of the bottle. Be sure that the tail from the knot of your wick extends into the growing media, to help wick the nutrients from below. Gently press it down.
For this project, you want something that is a mix of an inert material like coconut coir, perlite, or vermiculite, which will hold water and provide support for the plant. Grain or foam hydroponic media won’t work for this project. Check your local gardening center or home improvement store for supplies.
For your seeds, there are many options. I recommend a pinch of lettuce seeds for classroom projects. They germinate quickly and easy to grow. You can try herbs, like dill or basil. Smaller flowers work nicely too. Cucumbers and tomatoes will work as well, though you may want to scale up to a 2-liter bottle planter. Bare-root strawberries can be grown in larger planters as well. Whatever you do, don’t crowd your plants.
Once you’ve added your seeds, gently add sprinkle some of your nutrient solution over the growing media.
Grow your Veggies
Because the nutrients in the solution can be degraded by light, cover the reservoir with aluminum foil. Then place a bit of plastic wrap (or a used, cleaned sandwich bag) over the top. The plastic creates a greenhouse effect, keeping the growing media warm and moist while the seeds germinate. Once the first green leaves appear, remove the wrap.
Place your planter in a sunny spot and let the seeds do their thing. Check the reservoir every week to make sure it doesn’t run dry. Also check to make sure it isn’t too wet, as that can cause roots to rot. For coconut coir and similar media, it should look somewhat dry on the surface, but release water when you pinch the soil. If your planter is getting too wet, reduce the width of your wick or try changing to a different material.
Over time, wicks may transport less and less water, as minerals build up in the fabric. Replace your wick each time you replant.
As your plants grow, increase the concentration of nutrients according to the manufacturer’s directions.
Prefer video? No problem! Here are short instructions to create your planter!