FAQ : NUTRIENTS & PH

Regular hydroponic nutrients contain mineral elements (such as nitrogen, calcium, etc.) that are immediately available to the plant. Organic nutrients (such as bat guano or bone meal) must be broken down before the plant can absorb the minerals. Organic nutrients work great in soil because of the micro bacteria which increase the rate of this process. In hydroponics there are no beneficial 'helpers' so growth can be much slower as nutrients are not as quickly available to the plants. The plants are also at greater risk for nutrient deficiencies and need to be watched a bit more closely.

Another thing to be wary of with organic nutrients is their propensity to clog drip emitters, tubing and pumps. It will be easier to grow organically using an ebb and flow system (with no drippers) as opposed to a drip system with many narrow, small tubes.

Many growers use a mineral-based nutrient and supplement it with organic additives for the best of both worlds.

Organics can be great in hydroponic systems, but it is important to make sure that the root zone is protected. This can be achieved by creating a "beneficial ecosystem" in the reservoir and at the roots. To get more information look here Root Zone.

What is the difference between one-part, two-part, and three-part nutrient solutions?
The reason many nutrient solutions are separated into 'A' and 'B' formulas is because essential elements have a tendency to react with each other (thus creating insoluble, non-absorbable particles) when they are in strong concentrations. So usually the calcium containing compounds are kept separate from the phosphate and sulfate compounds. However, there are some great one-part solutions on the market made by different manufacturers who have found various ways of tackling this problem.

The three-part solution we sell is the General Hydroponics Flora Series. They have designed these nutrients to allow the grower to custom-tailor nutrient solutions to satisfy the needs of practically any type of plant during each different stage in its life cycle by varying the combination and overall strength of the mix. Thus with the three components you can provide the correct 'flavor' for every life stage of your plants.

How do I use the Flora® Series from General Hydroponics?
General Hydroponic's Flora® Series is the most commonly used hydroponic nutrient on the market. It can work extremely well if used properly. One of the beauties of the three-part solution is that you can adjust the ratios to suit your type of plant and stage of growth. General Hydroponics suggests the mixing ratios we've posted below. You will need to use an EC or TDS meter to know exactly how much nutrient to use - it depends on your desired nutrient level. Just be sure that you always mix the three nutrients in the correct ratio.

It is important to know that you should never mix the nutrients together. You should only add them one at a time into your watering solution/reservoir. Stir well between each addition to prevent nutrient lock-up.

What is the best temperature for my nutrient solution?
You should keep the nutrient solution temperature between 65 and 75 degrees F. Rremember, plants don't like rapid temperature changes, especially in the root zone. So before adding water to your reservoir, we suggest you allow it to reach the same temperature as the water in the reservoir. You can use an aquarium heater to heat the water in the winter and a "chiller" to cool the water during the summer. Also, letting the water stand in a container uncovered overnight helps dissipate any chlorine than might be in the water.

N = Nitrogen
Nitrogen is the first major element responsible for the vegetative growth of plants above ground. With a good supply, plants grow sturdily and mature rapidly, with rich, dark green foliage.

P = Phosphorus
The second major element in plant nutrition, phosphorus is essential for healthy growth, strong roots, fruit and flower development, and greater resistance to disease.

K = Potassium (Potash)
The third major plant nutrient, potassium oxide is essential for the development of strong plants. It helps plants resist diseases, protects them from cold and protects during dry weather by preventing excessive water loss.

What is pH?
pH is a measure of the acidity or alkalinity of a solution. A basic, neutral solution is numerically equal to 7. The solution gets more acidic as the numbers decrease and more alkaline as the numbers increase. The ph scale ranges from 0 pH (very acidic) to 14 pH (highly alkaline). Pure water has a pH of 7, indicating that it is neither alkaline nor acidic, but neutral. Different nutrients may be absorbed by plants at different pH levels.

What pH level should my nutrient solution be at?
The ideal range is different for different plants, but the general range for plant survival is between 5.0 and 7.5. Any lower and delicate plant tissues can be burned; higher and some nutrients may precipitate out of solution, making them unavailable for uptake. It is also important to take into consideration the fact that different nutrients can only be absorbed at certain pH levels. The optimum pH range seems to be between 5.8 and 6.5. . If you want to get real fancy, tweak the pH of your solution to allow more nitrogen in the growth phases and then readjust during the bloom phase for more phosphorous uptake. You'll need to manually test and adjust your pH daily, unless you use an automated controller.

What is PPM/TDS?
TDS stands for Total Dissolved Solids and is measured in ppm or parts per million. One ppm is one part by weight of the mineral in one million parts of solution. In a laboratory, TDS is found by allowing the liquid to evaporate and weighing the particles left over. In hydroponics TDS is estimated using a conversion from the measure of electrical conductivity (EC). TDS is currently the standard of measurement that most US growers use. This will probably begin to change in the future as hydroponic manufacturers begin changing their products to EC.

What is EC?
EC stands for Electrical Conductivity and is measured in mS/cm or miliSiemens per centimeter. An EC meter measures an electrical current in the solution and reads the conductivity produced from the motion of the mineral ions. Low conductivity means low nutrient concentration, often resulting in nutritional deficiencies and slow plant growth. High conductivity means more food for your plants. But be careful not to get overzealous with the concentration of your nutrient solution; very high conductivity can burn or kill your plants.

Which is the best way to to measure amount of nutrient in solution?
In Europe, EC has been used exclusively. In the US, most growers have been using TDS. The problem is that, as explained earlier, TDS is a conversion from EC, and different manufacturers use different conversion rates. Different TDS meters may show a discrepancy of as much as 600 ppm when reading the same solution. Last June at the Hydroponic Merchants' Association conference is was decided that the industry will begin to switch over to EC. This switch could take years however.

American growers still seem to want to use TDS meters most often and we supply a wide range of quality ones. Be sure when calibrating these meters to use the correct calibrating solution from the correct manufacturer.

How do I convert my readings from TDS to EC and vice versa?
To get the approximate TDS value, simply multiply the EC reading (in milliSiemens/cm) by 1000 and divide by 2. To get an EC value, multiply the ppm reading by 2 and divide by 1000.

For example if your EC is 1:
1 x 1000/2 = 500ppm

And if your ppm is 500:
500 x 2/1000 = 1E

What nutrient level should my solution be at?
For seedlings, your nutrient level should be between 400ppm (800ms) and 600ppm (1,200ms). For vegetative growth, the level should be between 800ppm (1,600ms) and 1,100ppm (2,200ms). For bloom, the level should be between 1,000 ppm (2,000ms) and 1,400ppm (2,800ms). These of course are very general levels.

How do I calibrate my TDS or EC meter?
It depends on the meter. You should follow the calibration instructions in the manual of your particular meter. Fortunately standard reference solutions are used. Nutrient bottles are marked with the conductivity (EC) value in microSiemens/cm and the corresponding ppM values for sodium chloride (NaCl) and potassium chloride (KCl) solutions, and sometimes a "442" reference mixture. Because the conductivity of sodium chloride solutions is close to that of hydroponic minerals, a "1000 ppM NaCl" standard the frequent standard for calibrating your meter.

My plant leaf tips are curling down and there are small rust colored dead spots beginning to appear in the middle of the leaves. What's going on?
The symptoms you describe are consistent with salt toxicity. Your plants are not able to take water up through their roots because there is too much salt in the solution. There are also probably too much salts lingering in plants roots etc.

The solution to this problem is to drain the reservoir immediately and fill it up with fresh water. You will use this fresh water to leach the salt from the plants over a period of days. You can use a flushing agent such as Final Flush or Clearex to speed up the process. Keep an eye on the TDS readings of your reservoir. If they go very high, you may want to drain the reservoir again and keep flushing. After a few days you should notice signs of more normal growth and can switch back to your regular nutrient schedule

What are some reasonably priced fertilizers/foods for my plants. Could you suggest one for vegetable growth and one for when I start flowering?
For starters, if you are looking for simplicity, we suggest the one part Flora Nova from General Hydroponics. It has a one part grow solution and a one part bloom solution. You can always add Hygrozyme for the roots or Liquid Karma for general health and metabolic enhancement. But of course you don't need them because Flora Nova is a complete nutrient unto itself.

If you are looking for en even better nutrient I would go with Advanced Nutrients Sensi Grow and Sensi Bloom. It is a 2-part nutrient, but easy to use. You need to add equal parts of A and B to the reservoir. You never want to mix them together unless it is diluted in the reservoir or watering container. So, to clarify, if you add 5 teaspoons of A then you will add 5 teaspoons of B as well. This method will give you a slight performance advantage over the Flora Nova nutrients. You can also take a look at the rest of the Advanced Nutrients line

How can I tell what nutrient deficiencies or excesses my plants are suffering from?

How can I tell if I am using too much VHO?
VHO is primarily made of Auxins - which is one of the primary growth hormones in plants. If you are using too much you can see a slew of disorders; necrosis, strange twisted growth, halting growth all together, etc. If used properly you will see the results that the bottle claims. You'll get more rapid shoot growth, more lateral branching, and more cuttings.

I've heard that the chemical nutrients used in hydroponics can be bad for me, is this true?
Not at all. The "chemical nutrients" that are on the market for plants are not toxic. They are mineral based nutrients that are mined and refined in a lab under strict standards. They do not contain any toxic materials. However if you are at all worried you can go with an organic nutrient line such as Pure-Blend Pro. We recommend; Pure Blend Pro Gro , Pure Blend Pro Bloom , Cal-Mag Plus, Liquid Karma, Hygrozyme, and HydroGuard. If you understand that the chemical based nutrients really are natural and are comfortable using them then we suggest either Canna or Advanced Nutrients.

What are metabolic enhancers? Do I need to use them?
Although hydroponic formulas have come a very long way in providing total plant nutrition, many vital compounds and biological agents are available to the plant in healthy soil are absent. When used correctly, metabolic enhancers can bridge the gap between organic and mineral nutrition. They can help the achieve full plant potential at every stage of growth.

• Better seed germination
• Stronger seedlings
• Faster growing, more vigorous clones
• Massive root systems
• Healthier vegetative growth
• Better resistance to pests and diseases
• Bigger plants, higher yields

What are flushing agents?
Flushes are used to rid plants of mineral and salt buildup. They can be used periodically during a growth cycle or just before harvest. Many hydroponic growers flush their plans with plain water, but salt leaching solutions can do a much more thorough job of it. Our current favorite flushing agent is Final Flush which also comes in flavors- you can flush out the salt and leave a sweet flavor if you so wish. (Many growers swear by this!)

Why do I need plant enhancers?

Although hydroponic formulas have come a very long way in providing total plant nutrition, many vital compounds and biological agents are available to the plant in healthy soil are absent. When used correctly, enhancers can bridge the gap between organic and mineral nutrition. They can help the achieve full plant potential at every stage of growth. Plant hormones and enzymes can greatly increase the metabolic functions within the plant, above and beyond what would occur naturally. Root enhancers do an incredible job of stimulating fuzzy white root growth, and promoting a healthy rhizosphere.

There are so many different things that can be added to my nutrient solution, where do i begin?
You should begin by understanding the different categories of additives that are available. Once you have this understanding, you will have a better grasp on what the individual additives do and which ones would be right for you to use.

There are many different products to choose from. We suggest prioritizing what is most important to you. Start with only one or two additives in addition to your regular nutrient. Watch for results and decide whether or not to add more. Be careful some products are not recommended for use with each other. As a rule of thumb, organic products can be used together, but the more concentrated mineral based products should be used more cautiously.

Preventatives
These products help protect plants against diseases and pest infestations. They do this by inhibiting pest and disease growth and by strengthening plant defenses

There are so many different products on the market, where do I begin?

The two most important enhancers are something for the roots and something for the yield. If you are on a budget and are looking to simply keep your reservoir sterile and that no pathogens hurt your precious root system, then go with Dutch Master Zone. It is cheap, and very effective. However, if you are looking to take your roots to the next level, we suggest giving Roots Excelurator from House and Garden a try. We have never ever ever seen a product this good in the hydro market place. It will blow your roots way out and give them a shiny fuzzy healthy glow that stays with them throughout their life span. (Do not use these two products together.)

Just about every grower is interested in bloom stimulants. These increase the number, size and density of fruits and flowers. Every line has their own set of bloom stimulants. Our favorite for early to mid bloom stage is Big Bud and for late stage, Overdrive. Both of these are from Advanced Nutrients. If you are want to kick it up another notch, we recommend Phosphoload for the early stage and Final Bloom for the late stage.

Be careful as some products are not recommended for use with each other. As a rule of thumb, organic products can be used together, but the more concentrated mineral based products should be used with more caution. We always suggest half strength applications at first, and never introducing too many new things at once as you build your nutrient routine.

Why do I need plant enhancers?

Although hydroponic formulas have come a very long way in providing total plant nutrition, many vital compounds and biological agents are available to the plant in healthy soil are absent. When used correctly, enhancers can bridge the gap between organic and mineral nutrition. They can help the achieve full plant potential at every stage of growth. Plant hormones and enzymes can greatly increase the metabolic functions within the plant, above and beyond what would occur naturally. Root enhancers do an incredible job of stimulating fuzzy white root growth, and promoting a healthy rhizosphere (root environment).

Do you recommend any specific products? What are some winning combinations?
For beginners we really recommend using SM-90. It's very easy to use in the reservoir and it discourages root disease while encouraging new growth. We've had great results with it and have seen its amazing capabilities for giving new life to severely damaged roots. SM-90 does not work well with other biologically active products. We suggest using it with a regular nutrient throughout the growth cycle, and then if at the end you are hoping for large fruit or flowers, adding Monster Bloom. (These two products do not interfere with each other and can be used together.) Monster Bloom's high phosphorous content promotes rapid and lush bloom sets. It's another of those products that we know REALLY works. For the last four days of your harvest you could use a flushing agent such as Final Phase. This should remove all excess salt from your final product.

A second combination that we often use relies on organic substances to add that 'organic' flavor to the harvest. Organic additives are not as strong or concentrated as refined mineral additives and therefore there is a bit more leniency when it comes to dosage concentrations and combinations. We suggest adding one organic additive at a time. As you get good results from the first, go ahead and add the second. Always watch your plants to see how they react. In addition to our nutrient solution we have had good results combining fulvic acid with Fossil Fuel (with humates). As soon as flowering starts, Kelp can be added to this mixture. You may also choose to add Pro-Silicate to promote healthy cellular growth. A final additive you might choose is BananaMana (this is great for any kind of fruits or flowers that produce resin).

When I add certain solutions to my reservoir, I see a blue cloud. What does this mean?
If the solution you are adding is colorless and you see a cloud forming, what you are seeing is ions reacting with each other to form insoluble salts. This reaction makes nutrients unavailable to your plants. In order to prevent this kind of reaction you should dilute the solution you are adding and add it very slowly while stirring. This will help to disperse the ions and will prevent them from clumping up.

How is hydrogen peroxide used in hydroponics?
Hydrogen Peroxide (H202) is made up of oxygen and water. When it breaks down, a single atom of oxygen is released along with a single water molecule. It leaves no residue or waste behind. The single atom of oxygen is what makes it so useful.

Hydrogen Peroxide has two main uses in hydroponics: disease fighting and aeration. It can be added regularly to nutrient solution in order to increase the amount of dissolved oxygen in solution. It can also be added to help fight root rot. At higher concentrations it can be used to sterilize growing medium, gardening tools, and plastic trays and pots.

How can I treat my water to prevent disease? Do I need to?
It is MUCH easier to prevent disease from occurring in the first place than to treat a full blown attack. We are very fond of using SM-90 in our hydroponic systems. It keeps plant roots healthy throughout the growing cycle and prevents disease from taking hold.

Other alternatives are using hydrogen peroxide in the solution, or Dutch Master Zone.

What is hard water? How do I know if I have it?
Any water sample containing more than 150 mg/liter of bicarbonates (HCO3) could be considered "hard". Hard water is found all over the world in different regions. It is characterized by high levels of mineral salts and it can cause problems for hydroponic growers.

Hard water usually has a very high pH and a grower will find that it takes a large amount of pH down to lower the pH. The hydroponic grower will usually add phosphoric acid (H3PO4) to lower the pH. As it takes a significant amount of phosphoric acid to lower the pH, the levels of phosphates in the solution will skyrocket. Over time, the phosphate will accumulate and the high levels will affect the uptake of other nutrients, such as zinc for instance. Major nutrient imbalances will not be far off.

You may be able to tell if you have hard water just by looking around your home. It is harder to get soap to produce a lather in hard water. Hard water also often leaves a buildup of lime on your pots and pans. The surest way to tell is to get a water quality analysis from your local water company, or if you like you could take a sample to your local hydroponic shop who could send away for an analysis.

If my water is hard, what should I do about it?
You have two choices when dealing with hard water. The first is to use a nutrient specially formulated for hard water such as Ionic, a one-part nutrient solution available in both Grow and Bloom formulations. These formulas are more acidic and are also specially formulated to take account of the minerals, such as calcium, that are usually present in hard water. By reducing these elements in the nutrient solution it is possible to ensure that the final solution comes as close as possible to ideal levels of the major elements.

A second choice is to go with a reverse osmosis unit. RO systems filter the water before it enters your reservoir, removing about 98% of inorganic salts.

How often should I change my nutrient solution?
A good rule of thumb is to always top off your reservoir with fresh water without any nutrient added. You will lose some water through evaporation and plant uptake, but the strength of the solution doesn't necessarily drop the with the level of the solution. Sometimes, as the reservoir water level drops the nutrient solution can actually become more concentrated. To avoid overdoing your nutrient, add only fresh water and then adjust your pH accordingly. The best way to know when its time to change your nutrient solution is to keep a record of how much water you're putting in the reservoir to top it off. When the amount added equals half of the reservoir capacity, it's time to change the solution and rinse the reservoir and growing medium. So, if you've got a 20 gallon reservoir and over the course of 12 days you've added 10 gallons -- it's time to change your solution.

How do I prevent/treat algae buildup?
The best way to handle algae is to prevent it from occurring. Algae needs light to grow, so keep your reservoir out of light. It should be shaded or covered with a lid. You should also take care to shade the input and output pipes and other 'wet' equipment.

If you already have an algae problem you should clean out your system thoroughly, using the method discussed below. When you refill your reservoir you may consider adding a product such as HydroShield to prevent further outbreaks in the future.

How do I clean my reservoir?
If you are cleaning your reservoir just to add fresh solution, you can follow the following steps:

• Remove all plant matter and debris that you can grab from the water.
• Drain reservoir.
• Wipe out as much residue as possible with a paper towel.
• Refill reservoir and add new nutrient solution.

How do float valves work?
Float valves work off of the same concept that your toilet works off of. When the water level of the reservoir drops, it causes the float valve to drop with it, thereby opening up the pathway for water to flow into the reservoir. When the reservoir is filled up again, the float valve rises back up with the water and closes off the pathway, thus restricting water from passing through.

A watering timer is suggested to prevent unwanted floods from occurring. When your hydroponic system is running full steam ahead, the last thing you want is the float valve to drop, allowing EXCESS water into the reservoir.

When your system turns off and drains, there would be chance of too much water in the reservoir and the system could flood. The use of a watering timer prevents that. It turns on once or twice a day, when the hydroponic system is off, and allows the float valve to fill the reservoirs.