You don’t have to stick to any brand of beverage really, but Coke is popular globally. All you need is 2-liter soft drink (PET) bottles, though milk jugs and other types of large food-grade plastic bottles have a variety of gardening uses too. They’re easily recycled into more than one type of hydroponics system, along with more traditional forms of container growing.
The cost of them, as a growing container, certainly can’t be beaten. Depending on where you live, unreturned pop bottles cost 5-10 cents each, and in lots of places, they have no deposit, which means they’re free.
This is also known as a self-watering planter, or wicking – which is how seed starter trays work with the mat under the plant cells hanging into the water tray. It uses the same principle as Earthbox, but you need a wick. You’ll find people have good results with this setup using potting mix, vermiculite, and clay pellets.
One thing you really should do is paint the outside of the bottom half of the bottle to hamper algae growth in your reservoir. A lot of people leave them as they come. Why make more work for yourself when a little left over spray paint or the cheapest brand you can find solves the problem? Directions here.
Think that recycling used bottles is reserved for home growing? Not at all. A smart farmer will look for ways to make use of what’s on hand because new tools and equipment cut into farm profitability. This setup could be engineered in a greenhouse too – if you’re not blessed with living in the tropics, or used just for summer growing. This grower in Brazil has a sizable operation – all based on 2-liter pop bottles and hydroponics.
The screw top element of a soda bottle also lends itself well to a closed hydroponics system plumbed with PVC pipe. This can be small with 10 planting spots or less, and it’s also scalable to a commercial size growing operation. Here the nutrient reservoir is a separate container. Note that the portion of the recycled bottles used was painted on the outside. Don’t forget that roots are subterranean dwellers. They don’t want or need light. The sun is only supposed to shine on leaf and stem.
You’ll find plans to build this system here. As you can see it has infinite scalability. Look at all those bottles that didn’t wind up in a landfill. They will last multiple years being put to the task of growing food.
Whether you water by hand or hook up a pump, once again, the used Coke or PET bottle offers a sound planting container for growing up instead of out. You can take advantage of either method inside or outdoors.
These can work with a pump and utilize passive hydroponics too. It all depends on how you set up your system, which is many times determined by the available budget. You can also purchase a WindowFarms system, but this system design started with recycled bottles. This setup uses a pump to get water to the top tier plants, and drip irrigation to all those below.
Keeping seeds consistently moist so they will sprout is a huge challenge without the right equipment. Use the bottom half to cover the pot to keep the surface from drying out.
This works for container gardens, potted plants, and in the ground growing – depending on how you engineer your discarded bottle reservoir. The size of the bottle and your different needs will steer you to the right way to proceed. You can engineer the same setting using a drip catheter. You can jam a glass soda bottle full of water into a pot like these people. Or use the simplistic method of suspending the bottle with a tiny hole in the lid above your planters like you see here using recycled water bottles.
8. Plant Containers
What is the difference between the bottom part of a beverage bottle and a plant pot? Drainage holes, opaqueness, and perhaps a little stylishness. For some types of growing, portions of soda bottles, water bottles, and beverage jugs work great. Just make sure you’ve added adequate drainage holes first.
If you don't find her at the desk - check the gardens. When not writing and weeding, she enjoys a good book, painting junk furniture, and blending the harvest of heirloom tomatoes and chiles into salsas.