Miniature Deep Water Culture Hydroponics: a Pictorial Walkthrough

This is a step by step pictorial walkthrough of how to build and set up your own cheap, easy, and effective Deep Water Culture hydroponic system. It will work with any small leafy vegetables like herbs, lettuces, and leafy greens. It can also be placed at the base of a trellis and be used to grow vertically trainable plants like tomatoes, cucumbers, peppers, and berries. It can be used outside under the sun, or inside under a grow light.

Here are three Ruby Red Swiss Chard seedlings that are about 3 weeks old. They were germinated in a paper towel, and then placed in Jiffy-7 peat pellets to root. I have them placed in clear plastic containers with vermiculite to begin their root system before putting them in the hydroponic system. I've given them plain water at a pH of 5.5 (more on that later), with two light feedings (at one week and two weeks from seedling transplant) to help them push roots and start leaf growth. I can see roots on the inside of the clear container, so they're ready to go!

This is a 1 gallon Rubbermaid tub from Walmart that I have covered in a double layer of black duct tape to make it light-proof. The rest of the materials are three 3" net pots, a bag of lava rocks, and black plastic 1/4" hose all from the local garden center/hydroponic store for around $12, and the elbow and T fittings, air stones, and air pump, also from Walmart. Total Walmart purchase was approximately $20.

Total investment: approximately $32

Two aquarium air stones, some elbow and T fittings, 1/4" irrigation/air hose, and a small aquarium air pump, rigged in place with a braided wire to keep it centered on the bottom of the tub.

Here you can see the bubbles that will provide the oxygen needed for healthy plant growth (more on this later). These bubbles will keep going 24/7, as long as the plants are in there.

Even after thoroughly rinsing the lava rocks, I've ran the system with plain water for the last 24 hours to rinse out any remaining dust from the rocks. This step should be done with all natural aggregate media like gravel, or hydroton. The dust won't cause a problem in a DWC system; it just makes the reservoir dirty. In an active hydroponic system with water pumps and irrigation lines, the dust can clog the lines and damage the pump.

BioThrive Grow is a vegan organic nutrient solution that provides all of the major nutrients needed for vegetative plant growth. BioThrive also has a Bloom formula for use during the flowering or fruiting phase of plant growth, but since I am only growing lettuces, greens, and herbs in the vegetative growth cycle, I only need the Grow formula.

Full strength is 3 teaspoons per gallon, but I use just 1t for the first feeding to be gentle on the plant and give it time to acclimate to the nutrients. This nutrient is all you really need to grow herbs and leafy lettuces, though I also use few other ingredients. I use a measuring syringe made for baby medicine to precisely measure the nutrients. You can find them in the baby medicine section of your local drugstore.

FloraBlend is a vegan plant booster that supplies the micronutrients, enzymes, and organic acids needed for strong, vigorous growth. It isn't necessary, but it helps to increase plant health and growth rate.

Regular dosing is 1.5t per gallon, but for the first feeding I only use .5t.

CaMg+ is a calcium and magnesium supplement. These minerals are necessary for building a strong cellular structure, increasing nutrient uptake, and helping the plant to fight off illness and disease. Calcium and magnesium are usually present in high enough quantities in soil, but hydroponic nutrient solutions need a boost for optimum plant health.

Regular feeding is 1-2t, but I use .5t for the first feeding.

Hygrozyme is an organic enzyme solution designed to maximize the health of the roots. The enzymes are formulated to decompose dead organic matter. This helps the plant by cleaning away any dead or rotting root matter, which stimulates clean, healthy, vigorous new root growth. It also helps the roots to break down the nutrients in the solution to better absorb them. Not necessary for growing, but I consider it a secret weapon. It's like a natural, organic plant steroid (Organic Materials Research Institute -OMRI- approved!).

It can be used as much as 3t per gallon, but I start with just .5t for the first feeding.

*shake shake shake shake*

It is time to check the pH of the nutrient solution. Plants need the nutrient solution to be within a certain range to properly absorb nutrients; between 5.5 and 6.5 for hydroponics. If the pH is too high or too low (the liquid is too acidic or basic) the plant cannot absorb nutrients, and will begin to show deficiencies even though there are plenty of nutrients in the reservoir. Checking pH is not as big of an issue for growing in soil (except in the extremes), but maintaining the proper pH is an absolutely critical part of growing hydroponically. If you skip this step, your plant will not grow well, if it grows at all.

I fill a test tube half way with nutrient solution.

I use a chemical pH testing kit made by General Hydroponics to test my pH. You can buy an electronic tester, but it costs quite a bit more.

If the reagent turns the solution red, it is acidic. Green is basic. Yellow is right in the middle, where I want to be.

It seems that the solution is quite acidic, as it has a very low pH at <4.

General Hydroponics makes two chemicals, pH Up and Down, which are food-safe base and acid solutions that are designed for adjusting the pH of hydroponic systems. They are highly concentrated, so I only add a little bit at a time to dial it in.

*shake shake shake shake*

I wanted yellow, not yellow green!

This is the counterpart to pH Up. They are very conveniently color coded to prevent confusion.

My arm is getting tired.

The pH test sample is yellow, which is 6.0, right where I want it.

I swish the seedling in the water to rinse off the vermiculite. I want to get rid of as much as possible, since I don't want it floating around in the nutrients.

Spraying the roots helps to clean the vermiculite particles off of the fine delicate feeder roots.

After rinsing the seedlings as clean as possible, it is time to set up the system!

I like to pour the nutrients from a height of a few feet. It is an old trick I picked up from home brewing. The bubbles and splashes help to fully oxygenate the liquid. It isn't necessary, but I do it to have as much oxygen in the water as possible from the beginning.

I'm sure you've heard of someone killing a plant by over watering, but that term is actually a misnomer. The plant actually dies from suffocation once it absorbs all of the oxygen from the stagnant water. It is the lack of oxygen, not the presence of water, that kills the plant. This fact is the key to hydroponics. By maximizing the amount of oxygen in the nutrient solution, the plants roots can absorb the optimum amount of nutrients without ever being over watered.

Hydroponic plants grow much more vigorously than their soil-grown counterparts. This is because hydroponic environments are simply more ideal for plant growth. In soil, a plant must expend a large amount of energy on growing roots to search for water and nutrients in the ground. In hydroponics, all of the water, oxygen, and nutrients needed for the plant to grow are readily and easily available, which not only means that the plant can absorb more nutrients, but it also allows the plant to devote far more energy to the vegetation, rather than sending out an expansive root system. HOORAY FOR SCIENCE!

Be sure that you don't let the roots dry out for even a second. They are very delicate, and can die if they dry out.

I begin by putting a layer of lava rocks into the first net pot, skaing it down to make sure that it is even and compact, filling in as much space as possible.

Ready to go into their new home.

These are the fine, delicate feeder roots. Some of the roots have turned a pretty red color; a characteristic of the Ruby Red Chard.

I place the peat pellet onto a layer of lava rocks that is deep enough so that the top of the pellet is just below the level of the top of the pot.

I pour in lava rocks, making sure to fill the gaps as well as possible. I have to be gentle with the roots though, as they are extremely fragile.

And now we grow! Updates to come.