The topic of hydroponics would take a library to cover in full, but we will discuss some of the basics here so that you can get a better understanding. You will find it to be intriguing and fascinating as you learn that plants really do not have to have soil in which to grow. In essence, soil serves only two main purposes: (1) to nourish and (2) to support the structure of the roots. Both of these can be provided without the mess by taking advantage of hydroponics. Many people do not realize that roots need oxygen just like humans do. When the roots are buried in thick and compressed dirt or clay, the roots get very little to no oxygen. Hydroponics will often times produce a larger and more supple crop because it allows a much better airflow as well as a perfect balance of nutrients. The better exposure to oxygen virtually eliminates the chance of fungus and thus the need for fungicides. Because most hydroponic systems are used indoors (or in a greenhouse), most pests are non-existent as well. The end result is a crop that never had to be exposed to any chemicals of any kind, which leads to healthier plants and fresh organic produce. So now let’s take a look at how it all works.
In hydroponics, dirt is never used. Even when starting your plants from seed, an alternate medium is used. Any media can be used as long as it is inert (no nutrient value and with a neutral pH). The most common forms of media include hydroton, peat moss, perlite, rock wool, pea gravel, marbles… Every grower has his or her preference for certain reasons. Hydroton is clay pebbles that have been heated to form hard round pellets, and it is definitely a very popular medium. Because airflow is key in hydroponics, the medium should be able to retain moisture without remaining saturated. Hydroton absorbs moisture but because of the marble-like stacking, air space is ample.
When starting your plants from seed, peat moss or rock wool provides a great germinating atmosphere. It locks in moisture just as soil would to allow the seed to sprout and to give the roots something solid to grasp. When the seedling has grown enough root structure to be transplanted, the entire rock wool cube or peat moss pellet can be transferred as well. Mesh pots are used to house the root system for the remainder of the plant’s life when grown in hydroton. This allows the nutrient solution and oxygen to have full access to the entire root system. Over time, the roots will expand through the mesh pots and into the bare solution. You will also notice that the root structures will be smaller than in dirt, which explains why hydroponics takes so much LESS space than in conventional field cultivation.
The nutrient solution is probably the most sensitive part of the entire hydroponics topic. It’s not complicated to understand, but it does require an understanding that not all plants require the same balance of nutrients. The balance of solution is displayed with the N-P-K units. N – Nitrogen; P – Phosphorus; K – Potassium. An example would be: 20 – 20 – 20. The numbers are percentages of each corresponding element (20% N, 20% P, 20% K). Most solutions have other trace elements in them as well that are very necessary for plant growth but in less quantities than nitrogen, phosphorus, and potassium. There are about 17 elements that are needed, including oxygen. The NPK units need to be of different ratios depending on what your plant is and at what stage of growth it is. We can help you with all of those decisions.
Most solutions come in a powder concentrate, liquid concentrate, or dissolvable pellets. Each of these has various pros and cons. The powdered form requires less of a shipping cost and is highly soluble in water, so this is our preference and what will be shipped with our systems by default. If you’d like another form, just let us know.
The nutrients can be measured for the concentration value in PPMs (parts per million). PPMs are very important to monitor, because if the plant requires a range of 700 to 1200 PPMs, but you are only providing it with 500 PPMs, you will not get the same healthy and fruitful benefits that you could be getting out of that plant. In some cases, you may create nutrient deficiencies which can change the color of the leaves or even starve the plant. It’s as simple as adding more nutrient to the solution to adjust this. The other example is for having the PPM too high. Say your plants can only withstand a range of 500 to 700 (ideal for lettuce), but you’re supplying it with a PPM around 1200; you will burn your plants. This would be a nutrient burn that will almost always result in the complete loss of that plant, which is very common in seedlings when you try to give them an early jumpstart. Also note that your solution should never be allowed to get too hot during the summers, otherwise the roots will not be too happy with you.
The pH of the nutrient solution mixed in water is important to monitor as well. Most vegetable and herb plants prefer a range of 5.5 to 6.5. If your water is higher than this, don’t get too upset just yet. The nutrient solution usually buffers the pH and will make it safe for your plants. If it’s still too high, there are pH buffers available. There are also inexpensive meters to measure both PPM and pH levels. You will want to change out your nutrient solution every 3 to 4 weeks, but don’t just flush it or anything. That used-solution is still more nutritious than anything your outside plants are getting right now. Go ahead and let them have it all.
In hydroponics, there are various branches and methods to get the same job done. Each of them has strengths and weaknesses and is better for certain kinds of plants.
Ebb & Flow Method
There are a variety of system designs to use with this method. The most commonly used design is to use growing trays filled with a medium such as pea gravel or hydroton. The plants are usually planted directly in the medium without the use of mesh pots. A pump inside the nutrient reservoir turns on and fills the growing tray up to the base of the plants. After about 10 to 20 minutes, the pump is shut off, and the solution naturally flows back down into the reservoir. A timer is used in this method to keep a steady feeding schedule every day. An air pump may or may not be used to keep the solution and the roots oxygenated.
Methods such as the Bato Dutch Bucket system use this hydroponic concept. Hydroton is usually not used here while another medium such as perlite or pea gravel takes its place. Mesh pots are also usually not used. A growing tray or bucket is the supporting structure for the medium. Plants sit in the perlite or gravel with a small drip tube resting somewhere near the base of the plant. The idea is to have a constant slow drip so that the medium is just moist enough to sustain the plant without complete saturation. The nutrient flows through the medium and down into a trap-reservoir at the base of the growing tray or bucket. This is NOT the reservoir that holds the source nutrient, but it collects the used nutrient and sends it back to the source reservoir by way of natural gravity flow and/or siphoning. Using this method is necessary for most root crops and vine crops which usually have larger and thicker root systems as well as larger foliage.
NFT (Nutrient Film Technique)
When people think of hydroponics, this is usually the most popular idea that comes to mind. The NFT systems use less water flow but usually run 24 hours per day. In practice, any crop could live in this environment, but it is most commonly used for leafy crops, such as lettuce, spinach, water cress, Swiss chard, celery, etc. The “film” part of the term comes from the fact that the nutrient is flowing through the pipe at such a slow rate, that it appears as thin film. The “film” effect is created by the use of an adjustable or weaker pump, or you could use a strong pump but dilute its flow with additional pipes. The roots absorb the moisture and will eventually grow out through the mesh pot. As the plant grows, the roots will reach the film of solution and have better access to absorb more nutrient and oxygen.
Raft Float Method
This is the absolute easiest and most maintenance-free method of all. Any container will do as long as light cannot get to the roots, but the most popular are tubs and aquariums that have been wrapped to block light. Roots do not like light too much because it encourages algae growth. The container holds the nutrient solution for the entire growing period, and a foam raft floats on top as the nutrient level changes over time. Mesh pots are fitted into the raft to be held afloat, and an air pump provides fresh oxygen to your solution and roots. This method can only be used to grow leafy plants that like to sit in water their entire lives. The only maintenance needed is rinsing the container and changing the solution once every 3 to 4 weeks. This is a very inexpensive way to have a constant supply of fresh greens.
True aeroponics actually uses NO growing medium. The roots would ideally be supsended in air while a mister or fogger hydrates them. Neoprene inserts are used to hold the base of the plant to the mesh pot while the roots dangle freely in the air. Aeroponics has so many methods of its own that a lot of people consider it to be a completely different form of growing and completely detached from hydroponics altogether. However, aeroponics is still a branch of hydroponics. The greatest advantage of aeroponic methods is that the roots are exposed to fresh oxygen 100% of their life while still being fed the perfect balance of nutrients at just the right times. Some aeroponic systems use media such as hydroton in the mesh pots while still calling it “aeroponics.” This is because the nutrient is misted directly at the media and roots (rather than submerging them, as in other methods) while still allowing oxygen to them at all times, even while feeding. It is common to still use an air pump to aerate the nutrient at the bottom of the reservoir; however, any system that allows the solution to fall back into reservoir will create bubbles upon impact and naturally keep the solution aerated.
The use of a fogger creates 100% humidity which creates a natural fog within the system. A fog-rich solution is said to be the best plant-ready source of nutrients to deliver to your roots. Some systems use the mister method in conjunction with the fogger method.
This method is perhaps the coolest of them all. This is exactly like the Ebb and Flow method in every form, but the major difference is that it uses fish to supply the nutrients. This is also known as “aquaculture,” because you grow both vegetables and fish within the system. Gardeners have used fish waste (also known as fish emultion) forever as fertilizer. It is this same concept that is used more efficiently. In hydroponics, this is one of the most organic methods possible. Any coarse, inert growing medium can be used, such as hydroton and even lava rock. When the nutrient rich water is pumped from the fish tank into the growing bed, the water is filtered through the growing medium and dumped back into the fish tank much cleaner. The fish emulsion is retained in the medium where the plants’ roots feed. Since the plants and fish absolutely depend on each other to survive, the result is a self-sustaining ecosystem that produces healthy fish and crops. Since the nutrients are naturally provided, the only thing the grower must contribute to the system is fish food and electricity to keep the pump running. There are many kinds of fish that can be used in this system.
I have started an aquaponics system, and I have had great success with it so far. For now, you can see pictures and track my progress in the photo gallery.
Enough Reading! Start Your Own Hydroponic Garden Today!
If you have any questions about hydroponics or our products, please feel free to ask! There is definitely a lot of information to absorb, but we hope this helps you to see how awesome hydroponics really is. Check out our Photo Gallery and Product Catalog to see what you could have at your own house!