Hydroponics FAQ
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What are hydroponics and DWC?Hydroponics is the act of growing plants, but not using soil, instead the medium is mostly water. Deep Water Culture refers to a specific style/technique of hydroponics systems where the majority of the root system is submerged in oxygenated water and nutrients. In soil, plants send out a network of roots to seek out water and nutrients. In hydroponics the water and nutrients are "delivered" to the root base with little energy expended by the plant to produce roots to obtain water and nutrition. This results in superior growth rates and bigger yields with plants grown successfully in hydroponics.
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What kind of water should I use?
The best possible water choice would be distilled. With a TDS PPM of zero (aka distilled water) allows us a "clean canvas" on which to "paint" our feeding schedule on. Obviously distilled water is expensive and not readily available, so we go with very well filtered water, preferably RO (Reverse Osmosis) filtered water tends to be the best overall choice as it is cheap as well as a low TDS PPM (usually less than 10).
Municipal water is filled with all kinds of contaminants. Chemicals such as chlorine, fluoride, pesticides, lead, and copper are very common and are extremely harmful to your plants. Many of these chemicals interfere with the absorption of nutrients. Tap water has a high likelihood of interfering with the pH of your nutrient water.
This is not to say that all non filtered water sources are inadequate, however, if any of the above mentioned symptoms show up, change the water source immediately.
Municipal water is filled with all kinds of contaminants. Chemicals such as chlorine, fluoride, pesticides, lead, and copper are very common and are extremely harmful to your plants. Many of these chemicals interfere with the absorption of nutrients. Tap water has a high likelihood of interfering with the pH of your nutrient water.
This is not to say that all non filtered water sources are inadequate, however, if any of the above mentioned symptoms show up, change the water source immediately.
Which nutrient recipe is right for me?
Nutrient regiments are really a personal preference as there are thousands of products on the market to fulfill this function leaving us with an almost infinite amount of nutrient combinations and feeding regiments.
First timers should stick to simple nutrient recipes. A complete one part nutrient formulation (GH FloraNova), any A/B liquid two part or liquid three part (grow, bloom & micro) on the market at the moment will suffice. Do this until the use of the chosen nutrient base has been mastered. The idea here is to have the least amount of components possible, so that if something goes wrong, we don't have to eliminate 30-40 various aspects of the grow, instead we'll only have to sort through 5-8 aspects to troubleshoot.
The following recipe that I use will compete with the performance level of any high dollar, 10-20 part, weekly changing regiments. Some of which can cost up to $1000 for a modest indoor garden. The following recipe should cost no more than $100 for multiple harvests.
The above recipe is called a Lucas Formula. A very convenient system for growers with a little experience looking to step up their hydroponics game to the next level. The Lucas Formula is the perfect recipe to do this with as it never changes so what you mix up every feeding is always the same stuff at the same ratios.
First timers should stick to simple nutrient recipes. A complete one part nutrient formulation (GH FloraNova), any A/B liquid two part or liquid three part (grow, bloom & micro) on the market at the moment will suffice. Do this until the use of the chosen nutrient base has been mastered. The idea here is to have the least amount of components possible, so that if something goes wrong, we don't have to eliminate 30-40 various aspects of the grow, instead we'll only have to sort through 5-8 aspects to troubleshoot.
The following recipe that I use will compete with the performance level of any high dollar, 10-20 part, weekly changing regiments. Some of which can cost up to $1000 for a modest indoor garden. The following recipe should cost no more than $100 for multiple harvests.
- GH FloraNova Bloom - Complete Nutrient Formula. Cost: $30 for a quart, very concentrated
- Botanicare Silica Blast - Stimulates stem development to increase capillary transportation of nutrient elements. Cost: $17.50 for a quart, use at half the recommended strength.
- Botanicare Sweet (any one of the line; Raw, Citrus, Berry & Grape) quantifies the natural fragrance of the plant and also increases terpene and tannin production. Cost: $20.99
- Botanicare Aquashield or Botanicare Hydroguard - A bacteria that consumes and helps control pythium levels (a pathogen that causes root rot). Cost: $14.50 per quart, use at 2ml - 4ml per gallon. Hydroguard will replace Aquashield soon but is 2-3 times more concentrated in the specific strain of bacillus subtillus levels with no NPK value (i.e. a lot more refined than Aquashield). Cost of Botanicare Hydroguard: $30 per quart; 1-2 ml per gallon.
The above recipe is called a Lucas Formula. A very convenient system for growers with a little experience looking to step up their hydroponics game to the next level. The Lucas Formula is the perfect recipe to do this with as it never changes so what you mix up every feeding is always the same stuff at the same ratios.
How do I deal with pH levels?
As plants extract their needed nutrients from any hydroponics solution the potential hydrogen (pH) of that solution will increase. This is more pronounced as plants grow larger, requiring more nutrients. Modern day nutrients contain "pH buffers" that help keep the nutrient solution at the perfect pH, however, the buffers can only do so much. Once a plant "outgrows" its system, it will start affecting the pH of the nutrient solution.
Regular checks on your system will help you "dial in" the pH so that you will be able to anticipate changes and make the necessary adjustments as they are needed.
If the pH drops below, or goes too far above, the plants optimum pH range for the absorption of nutrients, the plants will cease taking in anymore nutrients, which, in short order, the plants will begin to display nutrient deficiencies even though all the nutrients needed are in the solution already. We call this condition "nutrient lockout".
Many folks will diagnose a specific nutrient deficiency and apply more of the nutrient that appears to be deficient which, obviously, will do little to fix the problem. In fact, this incorrect diagnosis can lead to over fertilization; which in hydroponics can lead to plant death within hours.
Regular checks on your system will help you "dial in" the pH so that you will be able to anticipate changes and make the necessary adjustments as they are needed.
If the pH drops below, or goes too far above, the plants optimum pH range for the absorption of nutrients, the plants will cease taking in anymore nutrients, which, in short order, the plants will begin to display nutrient deficiencies even though all the nutrients needed are in the solution already. We call this condition "nutrient lockout".
Many folks will diagnose a specific nutrient deficiency and apply more of the nutrient that appears to be deficient which, obviously, will do little to fix the problem. In fact, this incorrect diagnosis can lead to over fertilization; which in hydroponics can lead to plant death within hours.
How do I maintain nutrient levels?
TDS = Total Dissolved Solids. It tells you what percentage of the water has dissolved elements. If you started with water that has a low TDS and added your favorite nutrient recipe, you can calculate, using the nutrient breakdown sheet provided, how many PPM of each nutrient is in your solution.
However, once the plants start eating and drinking we can no longer calculate what is left behind as we cannot know which of the nutrients the plant has consumed and which ones have been left behind.
However, keeping an eye on TDS levels can tell you some useful information. If PPM levels stay constant while the nutrient water solution drops you can infer that the plant is eating a balance mix of water and nutrients.
If the PPM levels rise as water levels drop one can interpret that as the plants are drinking more water than they are consuming nutrients. This condition is common in warmer environments where the plant is drinking lots of water to keep itself thermally cooled. You'll want to keep adding water to the reservoir to keep the rising TDS level in check.
If the PPM level drops as water levels deplete, this tells you that you plants are likely heavy feeders (which will usually also yield more) and/or the plants are most likely located in a cooler, humid environment where the plant does not need to transpire much. More frequent reservoir changes are required in this instance.
However, once the plants start eating and drinking we can no longer calculate what is left behind as we cannot know which of the nutrients the plant has consumed and which ones have been left behind.
However, keeping an eye on TDS levels can tell you some useful information. If PPM levels stay constant while the nutrient water solution drops you can infer that the plant is eating a balance mix of water and nutrients.
If the PPM levels rise as water levels drop one can interpret that as the plants are drinking more water than they are consuming nutrients. This condition is common in warmer environments where the plant is drinking lots of water to keep itself thermally cooled. You'll want to keep adding water to the reservoir to keep the rising TDS level in check.
If the PPM level drops as water levels deplete, this tells you that you plants are likely heavy feeders (which will usually also yield more) and/or the plants are most likely located in a cooler, humid environment where the plant does not need to transpire much. More frequent reservoir changes are required in this instance.
What do I need to know about air and water temperature?
Heat; the number one enemy to the indoor garden. Even on a temporary basis, heat can cause many problems for plants that result in a less than ideal product at harvest. When air temperatures exceed 78 degrees Fahrenheit bud structure starts to "stretch" in an attempt to increase the plant's ability to cool itself with airflow. This departs from the gardener's goal of growing dense and compact buds.
In addition, high air temperatures will also heat the hydroponics reservoir, planting medium and worst of all; it will heat your root ball, making it far more susceptible to pathogens. Furthermore, water's ability to retain dissolved oxygen is greatly reduced as it heats up. This is largely due to the increasing rate of dissipation as water heats up.
Traditionally we used to beat the heat with ventilation and/or air conditioning, however there is another way to help you plants deal with heat fluctuations.
For this solution we look towards nature. Time and time again folks come into our stores with heat issues in their indoor gardens. When I begin explaining the effects of heat on their plants they immediately start telling me that their outdoor plants survive 95+ degree days routinely with no ill effects.
Absolutely true; outdoor plant's roots extend well over 3 feet below the soil's upper humus layer. Down here the roots have access to cold water, usually around 55 degrees. On a hot day, plants increase their transpiration rate in order to pump more of that cool water up and through their capillary system helping the plant to "thermo-regulate" during these hot days.
Learning from this concept we realized the importance of continuous irrigation systems that can be cooled by a chiller providing indoor plants the same ability as their outdoor counterparts. Smaller units can use frozen two liter (or smaller to whatever fits) bottles containing fresh water to accomplish the same task; crude, but cheaper than $400-$600 chiller.
Please note, that only continuous flow systems like DWC systems and hybrid systems using DWC fundamentals like the Oxyponics® and Bubbleponics® systems will work using this method. These systems have the roots largely submerged in actively cooled water, hence the roots are far more influenced by the water temperature than some other systems that completely drain for several hours at a time.
Hydroponics solutions using a timer to drain the root zone for an extended period; where the roots are exposed to a "warm up" period; do not allow the plants the access to consistently cool water in order to maintain their natural method of thermo-regulation leading those plants to find other methods to cool themselves.
This is not to say that you can run your room with a constant air temperatures of 110 degrees plus, and cool your water temps to 60 degrees while expecting your plants to be impervious to that kinds of continuous thermal abuse. Chilling your root ball only gives your plants significantly more "wiggle" room as far as temporary temperature fluctuations are concerned.
For example, should the compressor in your air conditioner overheat and shutdown for a few hours, plants with a chilled root ball will weather a bad situation like that without any major issues. Whereas, a plant with an non cooled root ball could develop root rot within that same period, and even if the water cooled back down (once the compressor come back online) the root rot will continue to destroy the root ball if not treated.
Chilling the root ball keeps your root system healthy and free from pathogenic infection. This helps your plants survive more extreme conditions should your indoor garden suffer some sort of equipment failure that results in excessively warm air temperatures. Furthermore, high tech grow rooms with CO2 enrichment systems, require the air temps to be slightly warmer to help the plants absorb more CO2 by increasing the transpiration rate. However, we still need to keep the roots from overheating so the plant can efficiently benefit from the increased CO2 levels.
In addition, high air temperatures will also heat the hydroponics reservoir, planting medium and worst of all; it will heat your root ball, making it far more susceptible to pathogens. Furthermore, water's ability to retain dissolved oxygen is greatly reduced as it heats up. This is largely due to the increasing rate of dissipation as water heats up.
Traditionally we used to beat the heat with ventilation and/or air conditioning, however there is another way to help you plants deal with heat fluctuations.
For this solution we look towards nature. Time and time again folks come into our stores with heat issues in their indoor gardens. When I begin explaining the effects of heat on their plants they immediately start telling me that their outdoor plants survive 95+ degree days routinely with no ill effects.
Absolutely true; outdoor plant's roots extend well over 3 feet below the soil's upper humus layer. Down here the roots have access to cold water, usually around 55 degrees. On a hot day, plants increase their transpiration rate in order to pump more of that cool water up and through their capillary system helping the plant to "thermo-regulate" during these hot days.
Learning from this concept we realized the importance of continuous irrigation systems that can be cooled by a chiller providing indoor plants the same ability as their outdoor counterparts. Smaller units can use frozen two liter (or smaller to whatever fits) bottles containing fresh water to accomplish the same task; crude, but cheaper than $400-$600 chiller.
Please note, that only continuous flow systems like DWC systems and hybrid systems using DWC fundamentals like the Oxyponics® and Bubbleponics® systems will work using this method. These systems have the roots largely submerged in actively cooled water, hence the roots are far more influenced by the water temperature than some other systems that completely drain for several hours at a time.
Hydroponics solutions using a timer to drain the root zone for an extended period; where the roots are exposed to a "warm up" period; do not allow the plants the access to consistently cool water in order to maintain their natural method of thermo-regulation leading those plants to find other methods to cool themselves.
This is not to say that you can run your room with a constant air temperatures of 110 degrees plus, and cool your water temps to 60 degrees while expecting your plants to be impervious to that kinds of continuous thermal abuse. Chilling your root ball only gives your plants significantly more "wiggle" room as far as temporary temperature fluctuations are concerned.
For example, should the compressor in your air conditioner overheat and shutdown for a few hours, plants with a chilled root ball will weather a bad situation like that without any major issues. Whereas, a plant with an non cooled root ball could develop root rot within that same period, and even if the water cooled back down (once the compressor come back online) the root rot will continue to destroy the root ball if not treated.
Chilling the root ball keeps your root system healthy and free from pathogenic infection. This helps your plants survive more extreme conditions should your indoor garden suffer some sort of equipment failure that results in excessively warm air temperatures. Furthermore, high tech grow rooms with CO2 enrichment systems, require the air temps to be slightly warmer to help the plants absorb more CO2 by increasing the transpiration rate. However, we still need to keep the roots from overheating so the plant can efficiently benefit from the increased CO2 levels.
What do I need to know about air circulation and CO2?
In any indoor garden whether using a hydroponics solution or not, air circulation is often overlooked and can often be the most crucial aspect of the garden. Especially if the garden is contained to a small room or closet, the need to remove the warm "stale" air is essential. Not only can this serve as a functional cooling system (by removing the heated warm air and having cooler air replace it), but also serves to replenish CO2 levels. When plants are exposed to light strong enough for them to photosynthesize, the plant will consume CO2 and provide oxygen as its "exhaust". If one seals up a small area and does not replenish CO2 levels, plants will simply stop growing.
Some indoor gardens, especially rooms that are completely sealed using air conditioning (a dual hose or mini split unit that uses outdoor air to cool the compressor) to cool the room without sucking air out of the room will provide CO2 via artificial means and usually boost the CO2 levels to as high as 1500 PPM to increase growth rate of the plants. This type of CO2 enhancement is expensive to setup and operate, so it is not for folks just starting up. However, if the environment the grower is faced with is sealed and air conditioned, artificial CO2 production will be required.
Regardless of whether your garden is sealed (using AC) or vented (using a HIGH CFM inline fan) circulation fans to move the air around inside the room is also required. This purpose can be accomplished with just about any cheap, low flow fan; the smaller it is, the easier it will be to incorporate into the garden. Oscillating fans cover a larger area requiring less fans to cover the growing area.
You have adequate interior air circulation if you see the majority of the leaves moving side to side or back and forth, as if there were in a light breeze. This interior circulation is required because it is responsible for the removal of oxygen rich air surrounding the leaves to replace it with CO2 rich air. This facilitates the process of perpetual photosynthesis and resulting in constant and unimpeded growth.
Some indoor gardens, especially rooms that are completely sealed using air conditioning (a dual hose or mini split unit that uses outdoor air to cool the compressor) to cool the room without sucking air out of the room will provide CO2 via artificial means and usually boost the CO2 levels to as high as 1500 PPM to increase growth rate of the plants. This type of CO2 enhancement is expensive to setup and operate, so it is not for folks just starting up. However, if the environment the grower is faced with is sealed and air conditioned, artificial CO2 production will be required.
Regardless of whether your garden is sealed (using AC) or vented (using a HIGH CFM inline fan) circulation fans to move the air around inside the room is also required. This purpose can be accomplished with just about any cheap, low flow fan; the smaller it is, the easier it will be to incorporate into the garden. Oscillating fans cover a larger area requiring less fans to cover the growing area.
You have adequate interior air circulation if you see the majority of the leaves moving side to side or back and forth, as if there were in a light breeze. This interior circulation is required because it is responsible for the removal of oxygen rich air surrounding the leaves to replace it with CO2 rich air. This facilitates the process of perpetual photosynthesis and resulting in constant and unimpeded growth.
How do I find the weakest link?
Grow rooms are always limited by their weakest link. You can setup a grow room with the best lights and most cutting edge hydroponics system, but if you ignore the climate control it will limit the potential of your eventual harvest. The following list outlines the basic aspects that influence the growth patterns of your indoor plants:
- Air Temperatures
- Light intensity (lumens, PAR, spectrum)
- Water/Nutrient solution pH level
- Base Nutrient Availability; NPK
- Parasitic, fungal or harmful insect presence (e.g. spider mites, powdery mildew, etc.)
- Dissolved oxygen levels in the water/nutrient solution
- Water/medium/root ball temperature
- Air levels or accessible air within the root ball
- Room atmospheric CO2 levels; ventilation or artificial enrichment of CO2
- Micro Nutrient Availability
- Additive/Supplement/growth accelerant types and availability
- Root health enhancements (mycorrhizae, symbiotic bacteria, etc.)
- Air Humidity levels (some varieties are more susceptible than others)
How do I diagnose what is wrong with my system?
After eliminating your water as the potential problem, check for any of the following...
Underfeeding and Weak Nutrition
The entire plant, both upper and lower leaves, will show lime or light green in color. The plant will not eat, drink or show growth. It is time to follow the 8 Step Remedy.
Overfeeding, Use of Too Strong Nutrients
The leaves will curl downward. They grow very dark dull flat green and then the tips show signs of burn. It is time to follow the 8 Step Remedy.
Nutritional Lockout
You know that you have made recent PH adjustments. You might know you may have used too much of the PH Adjustment Solution. You may have failed to test the PH often enough. You notice the plants did not eat or drink because they did not consume the same amount of water they used yesterday. You see rust spots. The large lower leaves are prematurely dying and you are not in the BLOOMING or FLOWERING stage. It is time to follow the 8 Step Remedy.
Wind Burn
You had the fan blowing downward toward the upper side of the leaves, instead of blowing up through the node spaces or toward the lights. You observe the leaves becoming dry or even crispy, perhaps shriveling, and the tips curling upward. The leaves do not appear glossy, moist and vibrant. It is time to follow the 8 Step Remedy.
Water, Nutrition Solution or Roots Are Discolored Brown Or Have an Unpleasant Odor
You notice your water is becoming brownish in color, or smells distasteful. Your solution does not smell pleasant and appetizing like fresh lettuce. Your roots are not the same shade of white that they once were a week ago. It is time to follow the 8 Step Remedy.
Underfeeding and Weak Nutrition
The entire plant, both upper and lower leaves, will show lime or light green in color. The plant will not eat, drink or show growth. It is time to follow the 8 Step Remedy.
Overfeeding, Use of Too Strong Nutrients
The leaves will curl downward. They grow very dark dull flat green and then the tips show signs of burn. It is time to follow the 8 Step Remedy.
Nutritional Lockout
You know that you have made recent PH adjustments. You might know you may have used too much of the PH Adjustment Solution. You may have failed to test the PH often enough. You notice the plants did not eat or drink because they did not consume the same amount of water they used yesterday. You see rust spots. The large lower leaves are prematurely dying and you are not in the BLOOMING or FLOWERING stage. It is time to follow the 8 Step Remedy.
Wind Burn
You had the fan blowing downward toward the upper side of the leaves, instead of blowing up through the node spaces or toward the lights. You observe the leaves becoming dry or even crispy, perhaps shriveling, and the tips curling upward. The leaves do not appear glossy, moist and vibrant. It is time to follow the 8 Step Remedy.
Water, Nutrition Solution or Roots Are Discolored Brown Or Have an Unpleasant Odor
You notice your water is becoming brownish in color, or smells distasteful. Your solution does not smell pleasant and appetizing like fresh lettuce. Your roots are not the same shade of white that they once were a week ago. It is time to follow the 8 Step Remedy.
How can I recover from a problem?
Recover from any problem using the eight step recuperation and recovery procedure:
The above 8 steps should repair and remedy any health problems that your plants experienced within the next two to four days. Older damaged growth will probably not repair completely, however, new growth should display no further problems.
- Check the roots. If they are discolored, reddish or brown, or present an unpleasant odor, you have a problem. If they are weak, soft or mushy, your problem is more urgent. Also while checking the roots, observe the temperature of the water. If it is warmer than "luke warm" it needs to be cooled. These symptoms is what is referred commonly referred to as "root rot" or a disease known as PYTHIUM. Remove the dead brown roots by trimming them away with sharp scissors. Do not leave them in the tank. Purchase some Botanicare Aquashield or Hydroguard as well as hygrozyme (and "zyme" will do) and start applying them ASAP.
- Check the humidity and temperature of the grow area below the lights in the "growing zone" when the lights are on. A temperature of above 78 degrees or below 65 degrees will slow growth, but it is not a problem that will kill your plants, however heat damage will occur if temperatures are not restored to an ideal range. Temperatures below 60 degrees or above 95 degrees will stop growth. An extremely high temperature in the upper 90s or below 58 degrees can slowly result in death of your plants. The most efficient temps for growth are between 72 to 75 degrees. Any Humidity between 40 and 60 percent is acceptable and desirable.
- Check the "lights off, nighttime" temperature to ensure that temps are not dropping too low without the heat of the light. Anything below 60 needs to be fixed.
- Check the distance between the tips of the plant and the tip of the light bulb. If you observe yellowing or leaf curling tips, then move the lights one inch further away. A good rule of thumb if you use HID lights, is hold the soft palm of your hand at the leaf tip and see if the bulb is too warm to your hand. If you use compact fluorescent bulbs, we recommend a distance of three inches for 55 to 85 watt bulbs and 4 inches to five inches for the 105 watt and larger bulbs. More mature plants can handle the bulbs slightly closer.
- Check the position of your fans. Air movement is very necessary for the health of your plants, but too strong of a fan can cause wind burn. Direct your fan toward the tops of the plants and toward the lights. Never position the fan blowing strongly downward on the leaves. If you have variable speeds, use the SLOW speed.
- Add 2 teaspoons of hydrogen peroxide to a quart of water and add it to the tank of six gallons already in the tank. Wait ten minutes and then turn the water and nutrition solution pump off to prepare to drain the tank. Poor at least a cup of clean water through each grow cup, onto each rockwool cube and through the hydroton rocks.
- Drain or pump the tank empty as possible without damaging the pump by running it dry. Add two gallons of additional clean water with 1 teaspoon of hydrogen peroxide again and then drain it away too. Again, empty the tank as empty as possible without burning up your pump.
The above 8 steps should repair and remedy any health problems that your plants experienced within the next two to four days. Older damaged growth will probably not repair completely, however, new growth should display no further problems.