This is a fun and simple way to get into hydroponics gardening. 2 liter bottles make excellent hydroponics containers and they're cheap. I've had excellent results growing lettuce in them, and you don't have to water very often at all. Like my other favorite hydroponics methods, these fit my requirements:
- Low maintanence
- Easy to find parts at local stores
- High yield
- Leak proof for indoor use
2 Liter Bottle Hydroponics
As you can see, the lettuce is very happy growing in 2 liter bottles. No mess and easy to setup.
This method will work well for all herbs, including basil, flat leaf parsley, cilantro, chervil, dill, fennel, and any other plant the produces lots of leaves.
Cut your 2 liter bottles in half. Many people recommend painting the neck half black under the misguided perception that the roots will not do well if exposed to sunlight. This is simply not necessary. It is hard to tell in the picture above, but I have done painted vs unpainted trials, and both did exceptionally well with no noticeable difference between the two. In fact, I think that painting the plastic is a bad idea because you risk getting paint in your root zone, which could result in chemicals in your veggies.
Painted vs Unpainted
You can see that the painted bottles did not help the plants out any appreciable amount.
Stuff a piece of cotton t-shirt material in the neck of the top of your bottle to act as a wick. The wick will pull nutrient solution up from the water reservoir below and keep the growing media moist, but not so wet that the roots rot. Put the upside down neck in the bottom water reservoir and fill with a good hydroponic growing media.
I like to use a mix of coco coir and perlite. Anywhere from 50/50 to 75% coco 25% perlite will work. If you are using the General Hydroponics bricks (1 brick expands to 3-1/2 gallons), then plan on 1 brick per planting tray. Mix in perlite to fit. You can rehydrate the coco coir with a very diluted nutrient solution if you want to, but it's not at all necessary. In fact I've messed up more batches by mixing in nutes at the seedling stage than I can count. When in doubt, just start with plain tap water. Here's a compressed brick of coco coir.
After soaking it in water you get expanded coco coir.
Once it expands it's light and fluffy. This is one of the best media for hydroponics.
Coco-coir and perlite mix
Perlite is available in a plastic bag at your local garden center. Mix the coco coir and perlite together and you have perfect media to grow in.
You can mix coco-coir and perlite together to make a very nice growing medium. Mix roughly equal parts and it should look something like this.
Seeds or Transplants
This method is good for both seeds and transplants. If you put transplants in, and they were started in soil you should be sure to clean all of the soil off the roots before planting them. If you plant seeds in your 2 liter bottles cover them with plastic wrap until the germinate.
Feeding Your Plants
Use a quality hydroponic fertilizer such as Pure Blend Pro Grow mixed at the rate listed on the bottle. It is important to use a hydroponic fertilizer because a traditional fertilizer will not work without soil. The microbes that are present in soil will not be present in your hydroponic grow media, so you need a nutrient source that the plant can metabolize on it's own.
You will not have to water that often at first, maybe once every coupld of weeks or less. Make sure that there is always water in the bottom of the bottles and the wick will keep the growing media moist.
Eventually the roots grow down into the reservoir (empty in this picture) and feed the plants.
This is an excellent method for getting started in hydroponics. I've had exceptional results with it.