Hydroponic / Aeroponic / Organic Soil Feeding

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Hydroponic / Aeroponic / Organic

Soil Feeding
How to Mix a Nutrient Solution
Mixing a nutrient solution can be as easy as doing what the fertilizer bottle says to apply. Most fertilizers’ recommended rates normally give a decent supply of the nutrients a plants needs. However, some are definitely better than others and are more specific to a specific plant’s needs. Brands such as Greenfire® Earth Juice, Welcome Harvest Farmtm, General Hydroponics®, Advance Nutrients®, Supernatural®, and others all give formulas for growing in soil, soilless, and hydroponic systems.

On the other hand, fertilizing can be made into a science depending on what the grower is trying to achieve. Some growers like to gain complete control over all the elements by customizing their formulas to particular feeding needs during all stages of growth. Determining the feeding needs of a particular strain is another important factor in working out a proper feeding formula so that a grower can give optimum nutrition and save costs.

It is possible to determine the parts per million (PPM) of a particular element such as nitrogen from the percentages of the elements listed on the fertilizer package.

Calculating Parts per Million
A chemical-fertilized nutrient solution should be at 1,000 to 1,500PPM to be on the safe side in most cases, but custom adjustments (i.e. 800PPM) can be made depending upon the plant. A TDS meter will give a reading in PPM (parts per million). Expensive meters measure a large span of elements and can be used to keep all feeding costs to the bare minimum because specific nutrients can be added when specific nutrients are used by the plants.

An organic, or a chemical-organic fertilized nutrient solution should be no higher than 1,500PPM. With an organic or a chemical-organic solution, a grower can push the quantity of certain elements because a lot of the fertilizer will not contain salts that hinder growth when they are in a solution in excess. For example, when Earth Juice® Grow and Earth Juice® Bloom are used to obtain the desired PPM of nitrogen and calcium, the PPM on a meter would be lower than if a solution of calcium nitrate was used to give the same PPM of nitrogen and calcium.

There will be dissolved solids in an organic hydroponic system from sources such as bat guano, Epsom salts (magnesium sulphate), sulphate of potash, humic acid, etc. However, some fertilizers will add nutrients but the PPM meter will not fluctuate. In a nutshell, this is the advantage of many organic fertilizers: no toxic salts. Results will be excellent if an organic solution is changed weekly, every 10 days, or every second week with a good fertilizing formula. A solution can go unchanged for longer periods of time with additions of new nutrients from time to time, especially when plants are small and don’t feed as much.

However, since plant nutrient requirements are always changing and some nutrient deficiencies are hard to detect, it is advised to change the solution regularly to save the hassle of determining what plant food is needed, and when. Also, just because plants are green doesn’t mean that they are growing at maximum production.

Monitoring a Hydroponic / Aeroponic Reservoir
Young Plants
Young plants tend to use more water than nutrient. Therefore, for the first 2 to 4 weeks, adding plain water to a reservoir is probably all that is needed, because solution will become saline (i.e. 1,800PPM) when a plant takes in water without much nutrient. Until plants start to use a decent amount of nutrient, it is not necessary to do complete reservoir changes because there are nutrients that have not been used by the plants. In most cases, 600 to 1,000PPM is adequate for seedlings and vegetative growth.

Aging Plants
It doesn’t hurt to make a solution on the weak side (i.e. 1,000PPM) until plants start to use equal parts nutrient and water, because PPM will rise as water is used by the plants.
When plants use equal parts nutrient and water, adding 1,000 to 1,500PPM concentrated solution is recommended.

When plants use more nutrient than water, adding a concentrated solution about 1,500PPM is recommended, unless a stronger concentration is needed to keep PPM at optimal levels. One should try to keep the PPM near 1,500PPM in the reservoir when liquid is added. This way, the solution will stay within the 1,000 to 1,500PPM boundaries, even as PPM slowly drops as plants use more nutrient than water.
When a reservoir needs changing (i.e. every 1 to 2 weeks), it is a good idea to allow the solution to run low. For example, if a full reservoir is at 1,500PPM, it is possible to allow water and nutrient to lower to a level such as 800PPM. This will give a little flush since the solution is a little on the weak side. And now there is only a little liquid to pump out of the reservoir before a new solution is added, thus minimizing maintenance.

A major factor worth noting is that larger reservoirs will have less fluctuations in PPM and pH and will keep maintenance down.

Two gallons of solution per plant in a top-feeding system is a good amount to put in a reservoir. This size compensates only for minor daily fluctuations in PPM and pH.

Plants that are close to intense light will use nutrient up more quickly than plants that receive less intense light.

When plants do not get the correct doses of food, nutrient deficiencies occur. When a deficiency occurs, plants normally change color from green to green-yellow to yellow. Deficiencies are often a sign that the reservoir needs a change, or specific elements need to be added to the reservoir.
When a deficiency occurs, it is recommended to give the plants the food they crave (i.e. nitrogen or calcium). Nitrogen is the most common deficiency.

Deficiencies should change within a day or two after the proper fertilizer is applied, and plants should go back to a healthy green, unless the deficiency caused serious damage.

How to Use and Clean a TDS Meter
A. The TDS meter electrodes should be rinsed with clean or distilled water, or isopropyl alcohol and water. A Q-tip helps scrub the electrodes free of debris.

B. Now the meter should be submersed in a calibrating solution (ie. 1,000PPM). A small container or the protective cap around the electrodes serves as a place to hold the calibrating solution.

C. The dial should be turned until the reading shows that of the calibrating solution (i.e. 1,000PPM).

D. The electrodes should then be cleaned again with clean or distilled water.
E. The meter should be dipped in the reservoir after the fertilizer is added.

F. Fertilizer (chemical fertilizers) or water should be added to adjust the reading between 1,000 to 1,500PPM.

If the PPM is higher than wanted, adding water can dilute the solution to the desired PPM range. The meter is actually useless in determining proper amounts of an organic or chemical-organic solution, but it is a good reference meter. There is a section in this chapter showing organic formulations and chemical formulations, and a section showing how to get the desired PPM of a specific element (i.e. nitrogen) in a fertilizer on pages 88 to 90.

Hopefully the water source is near 0PPM so that water is not stocked with unwanted PPM that can put limits on the amount of fertilizer added to a solution. There are many relatively inexpensive machines such as reverse osmosis machines and distillation devices that remove unwanted dissolved solids from a water supply.

Note: The PPM readings should only be used as a reference as to when to change solutions because they do not read the actual parts per million of a solution. Calculating parts per million of a particular fertilizer or element is best done with a little math and chemistry calculation as explained on pages 88 to 90.

Most meters are priced under $100. These measure PPM on a scale of 100 (i.e. 100, 500, 1000, 1100). For most people, these meters do the deed. However, there are expensive meters that measure a wide variety of elements in a solution. These tools are for an experienced hydroponic farmer.

Determining PPM without a Meter
Step 1
The percentage of the elements in a fertilizer (i.e. 20-20-20) is needed in order to determine the PPM.
The fertilizer packs are listed as NPK. N is all nitrogen, but phosphorous is listed as a compound (P2O5), and potassium is listed as (K2O).

Phosphorous (P) is 44% of phosphoric acid (P2O5), potassium (K) is 83% of potash (K2O).
To get the PPM from a 15-30-15 fertilizer, the first step is to take all three numbers and move the decimal one decimal place over to the right. In the case of nitrogen, the number would be 200. This number will give the parts per million of nitrogen when 1 gram is added to each quart or liter.
For phosphorous, a grower should multiply the 300 by .44. For example, 300 x .44 = 132PPM.This number will give the parts per million of phosphorous when 1 gram is added to each quart or liter.
For potassium, a grower should multiply the 150 by .83. For example, 150 x .83 = 124.5PPM. This number will give the parts per million of potassium when 1 gram is added to each quart or liter.
More Advanced Note: Some growers make their own plant food with 5 to 7 basic salts, as described on pages 95 to 96.
How to get the percentage of an element (i.e. K = potassium) in a compound (i.e. K2SO4).
Here is how to get desired parts per million of sulphur (S) and potassium (K) in potassium sulphate (K2SO4).

A. The periodic table of elements should be referenced in order to get the atomic numbers of each atom. For example, potassium has an atomic number of 19, sulphur has an atomic number of 16, and oxygen has an atomic number of 8.

B. Now, to determine the percentage of each element, all the elements must have their atomic numbers multiplied by the number of ions in a compound. In the case of K2SO4, the atomic number of potassium, which is 19, is multiplied by 2 to give 38, because there are 2 potassium ions. Since there is only one sulphur ion, 16 is multiplied by 1 to give 16. Oxygen has 4 ions in the compound, therefore 8 is multiplied by 4 to give 32.

C. Now all of the atomic numbers are multiplied by the number of ions, then all of the atoms multiplied by their atomic weights are added up. For example, the total number in potassium sulphate is (2 x 19) +16 + (4x 8) = 86.

D. To get the percentage of each element, the amount of ions is multiplied by the element’s atomic number. For example, in the case of potassium, 2 x 19 = 38.

E. The amount of ions multiplied by the element’s atomic number is divided by the sum of all the elements multiplied by their atomic numbers. In the case of potassium, the 38 (number of ions x atomic number) is divided by 86 = .44.
F. The number multiplied by 100 gives the percentage. For potassium, .44 x 100 = 44%.

Step 2
Finally, the percentage number should have the decimal place moved over one place to the right. In the case of potassium, the number would be 440. This number will give the parts per million of an element when 1 gram is added to each quart or liter. In the case of potassium , 1 gram of potassium sulphate in a quart of liquid will give 440PPM of potassium. Using half a gram per quart will give 220PPM of potassium and 95PPM of Sulphur.

Available PPM
The level of solubility (and purity) in water will make the final say. For example, some solutions and powders will completely dissolve into usable ions, while others will not be soluble in water, hence the elements will not be readily available to plants. For example, gypsum (CaSO4) is not very soluble in water, which makes it almost useless for hydroponic usage. However, gypsum does break down slowly in soil where it works fine. All formulas in this chapter are nearly 100% soluble in water.

How to pH a Solution
PH is the measure of the hydrogen ion concentration in a solution or other medium. There are more hydrogen ions in an acid solution than in a basic solution. On a scale, a pH of 7.0 is neutral, under 7.0 is acidic, and over 7.0 is alkaline. A plant’s intake of certain elements is greatly affected by pH. A pH of 5.5 to 6.5 is the standard for this organic hydroponic technique. A pH of 6.0 to 6.5 works well for vegetative growth and early flowering, while a pH of 5.5 to 6.3 works well during flowering.

A. The pH of plain water should be checked before adding the fertilizers. That pH number should be written down where it can easily be found. If the water pH is the same in the future, it is easier to make a quick formula using the same fertilizers without having to measure.

B. All of the fertilizers can be added and mixed well. The quantities should be written down for future reference.
C. A clean pH pen should be calibrated at 7.0, which is the pH reading of the calibrating solution.

D. The pen should be dipped into the solution and pH up or pH down should be added until the reading is in the preferred 5.5 to 6.5 range.
Examples of organic pH up are baking soda (sodium bicarbonate), Earth Juice® Natural Up and wood ashes. There are endless pH up solutions available anywhere garden supplies are available. Baking soda should be used carefully, because too much sodium is not wanted. Fortunately, sodium can be flushed out with plain water. The plants can absorb improper amounts of sodium if the potassium levels are not sufficient. Using feeding combinations that don’t rock the pH level means little or no pH up is needed.
An example of organic pH down is the addition of Earth Juice® Natural Down, and Greenfire® Earth Juice Grow. White flour and vinegar have been reported to work fine. There are many brands of pH down available.
Writing down the quantity of pH up or pH down that is added (for future reference) is a good method for putting together an identical solution in the future.

E. The electrodes should be rinsed in clean water before the meter is turned off.

pH Drift
The pH should be checked daily and adjusted if necessary because many fertilized solutions will drift significantly upward or downward in pH in less than 24 hours. Organic fertilizers tend to drift upward in pH after mixed, and may continue to do so a day or up to a few days after the solution is mixed. Adding molasses and avoiding certain fertilizers can keep the upward pH drift in a solution (organic or chemical-organic) to a minimum.

For fertilizer solutions with organic nutrients, pH drift is most common after the solution is mixed, and when certain nutrients in the reservoir run low.
Making an organic (or chemical-organic) solution a day or two in advance, with molasses (1.5ml per gallon of water) is a good starting point.

How to Use and Clean the pH Pen
If a pH pen is not cleaned after each day it is used, it can be hard to get accurate readings and it may not calibrate to the correct reading, especially if organic fertilizers are used. Using a cleaning solution before it is put away helps calibrate the pen accurately. The pen should be allowed to stay moist when it is put away. A few drops of calibrating solution in the bottom cap helps the electrodes stay moist. Cleaning the pH pen with clean tap water and a Q-tip works too, and saves money. When a Q-tip is used, it is recommended to gently pull the fluff away from the stick so that the soft cotton-batting can be moved between tough spaces. Care should always be taken with the glass, because it can break and start to give weird readings without a grower noticing the error.

After the pen is rinsed, pH buffer 7.0 solution is used to calibrate the pen. The meter should read 7.0. It may take several seconds to reach a stable reading. The pen can read 7.2 for a few seconds, and then it can slowly move down before it reads a constant 7.0.

A cheap bottle of pH 4.0 should be used once in a while to determine the condition of the pH meter in order to see that the pen calibrates at two different numbers, 4.0 and 7.0.

After the pH pen is calibrated, it should be rinsed well with clean water before taking a reading. The pen should be rinsed well with clean water after each reading. If the water is good, clean running cold tap water, the pen will often stay at one number when it is rinsed.

If the pH pen is really clean and calibrated properly, it should stay calibrated for several readings.

When the calibration does read differently it is probably because the pen needs a cleaning. If the meter is not clean and it is calibrated, all readings can be inaccurate. Weak batteries can also throw off the readings and make the pH pen function at a slower speed.

Hydroponic Mediums
Choosing a Hydroponic Medium
Choosing the proper hydroponic medium is the most important factor for a successful hydroponic garden. All mediums react to a fertilizing program differently, and the cost of mediums varies dramatically. Some local materials (e.g. fir bark, wood chips, small stones, and coconut fibers) are available locally for a cheap price. Most large-scale hydroponic farms use large quantities of local materials to keep the costs down, but a hobbyist may get better yields from commercial products such as clay, rockwool, or sterilized soilless mix that is cheap and convenient for smaller gardens. For a hobbyist, purchasing a hydroponic medium (e.g. rockwool) from the local garden shop may be a cheaper (and better quality) solution than tracking down a free medium.

For any medium, it is safe to feed for 3 to 6 days, then flush for 1 day with plain. An option with flushing is to use plain water and 1 to 2ml of hydrogen peroxide to defend against pests in the root zone. A grower can flush throughout a plant’s life cycle, until harvest is within two weeks. Two weeks prior to harvest, growers often flush out the medium with plain water, a clearing solution followed with plain water, or a low PPM solution (i.e. 0 to 400PPM) to get maximum flavor.

Preparing Mediums
Perlite compacts and should stand in a container of water for about a half hour. Fine particles of perlite will sink to the bottom of the water. The floating perlite is useful. The bottom of the barrel can go into compost or garden. Perlite is a good medium, but it does not cling onto elements. Therefore, plants must be well fed.

Clay floats, and should be soaked or sprayed until the water running through it becomes clear. Rinsing clay is similar to washing rice until the water runs clear. Clay is negatively charged and attracts positive ions such as calcium and potassium. Soaking rock-like mediums such as clay in water and 35% hydrogen peroxide (i.e. 2 to 5 ml per gallon of water) helps to sterilize the medium from any potential diseases. Sun heat helps sterilize mediums too.

Careful Alert: Perlite and other mediums can clog the feeding system and prevent the solution from pumping in or draining. All screens and filters may need a periodic cleaning and the pump should have panty hose (if used) cleaned during a reservoir change.

Reusing Mediums
All mediums (except disposable mediums like rockwool) can be reused if all roots are removed from the medium, and medium is sterilized between crops. For example, clay, soilless mix, and round stones can be used indefinitely. Mediums can safely be sterilized with an application of 35% hydrogen peroxide (approximately 5 ml per gallon of water). Most mediums such as perlite can be composted or used immediately to improve soil. For example, broken down wood chips can go into compost, while perlite and soilless mix can go directly into the garden.
Mediums should be cleaned as soon as a crop is completed to avoid molds. Molds often build up while a moist medium (e.g. clay) sits unused. If necessary, a citrus cleanser can be used to clean medium so that all molds and waxy buildup are removed. After the citrus cleanser is applied, the medium should be rinsed with plain water to remove the soap-like bubbles. A little leftover cleanser in the medium will not harm the plants.

Reusing Soilless Mix

When the indoor or outdoor crop is finished, soilless mix can be sterilized with calcium peroxide so that the medium can be reused to grow more crops. This is beneficial, because after each crop is done, the grow mix retains its investment value, since it can be reused indefinitely. Only new fertilizers need to be added for each additional crop. Chemical fertilizers can be applied a little heavier in areas of adequate rainfall because the mix will get a natural flush.

Organically Grown
When organic fertilizers are used (or very little chemical ferilizers) the mix will retain its quality.
All organic nitrogen sources, such as blood meal, fish meal, feather meal, earthworm castings, chicken manure, and canola meal are effective only for a single outdoor growing season.
Phosphorous needs to be replenished each year. Bonemeal and rock phosphate work well independently or as a combination.

Mineral potash sources, such as greensand and crushed granite, extend their usefulness beyond a single season. The minerals will break down slowly over time, releasing potash to the roots. Fast-acting potash, good for a single season, is available in kelp meal and wood ashes.
Kelp meal also provides most of the necessary trace minerals for the plant, but should be added for each new crop.

Hydroponic Feeding Formulas

Buying a pH buffered fertilizer is the easiest way to feed properly!!!
For Vegetative Growth
Most hydroponic formulas are purchased in 1 to 3 parts. Using any commercial product’s recommended rate works okay. The pH buffered fertilizers are most user friendly. Here are some basic formulas that work.

A. Calcium nitrate: 1.5 grams per liter (quart) or 11/2 teaspoons per gallon, dissolved in a small quantity of warm or hot water (1-liter) before adding to reservoir.

B. Potassium phosphate: 1/3 gram per liter (quart) or 1/4-teaspoon per gallon,
dissolved in a small quantity (1/2 to 1-liter) of hot water.

C. Potassium sulphate: 1/3 gram per liter (quart) or 1/6-teaspoon per gallon,
dissolved separately in warm or hot water.

D. Magnesium sulphate (Epsom salts): 1/4 to 1/2 gram per liter (quart) or 1/4-teaspoon per gallon, dissolved in warm or hot water (1-liter).

E. Chelated trace elements: 1/10-teaspoon per gallon or 1/2-teaspoon per 5 gallons, dissolved separately in warm water. Kelp, or kelp and a mineral powder can be used in place of chelated trace elements.

This solution mixture will be around 1,300PPM when read on a TDS meter. Solution should always fall between 1,000 and 1,500PPM, unless medium is being flushed with dilute solution (i.e. 800PPM) or with plain water (very briefly) to remove salts. The ph should be adjusted to fall between 6.0 to 6.6.

Option: Seaweed products, humic acid, and vitamin B-1 may be added in small quantities. The PPM should be no higher than 1,500 if other products are added.

For Flowering Stage
Most hydroponic formulas are purchased in 1 to 3 parts. Using any commercial product’s recommended rate works well. The pH buffered fertilizers are most user friendly. Here are some basic formulas that work.
A. Calcium nitrate: add 1.0 gram per liter (quart) or 1-teaspoon per gallon, dissolved separately in a small quantity of water (1-liter) before adding to reservoir. During late flowering, the calcium nitrate can be lowered to .5 to 1.0 gram per liter (quart).

B. Potassium phosphate: 2/3 gram per liter (quart) or 1/2-teaspoon per gallon, dissolved separately in a small quantity (i.e. 1/2-liter) of hot water.

C. Potassium sulphate: 1/5 to 1/4 gram per liter (quart) dissolved separately in hot water.

D. Magnesium sulphate (Epsom salts): 1/4 to 1/2 gram per liter (quart) or 1/4-teaspoon per gallon, dissolved separately in hot water (1-liter).

E. Chelated trace elements: 1/10-teaspoon per gallon or 1/2-teaspoon per 5 gallons, dissolved separately in a small quantity of water (1-liter) before adding to reservoir. Kelp, or kelp and a mineral powder can be used in place of chelated trace elements.
This solution mixture will be around 1,300 when read on a TDS meter. The solution should always fall between 1,000 and 1,500PPM, unless medium is being flushed periodically with dilute solution(i.e. have the PPM drop to about 800PPM) or with plain water briefly to remove salts.

The pH should be adjusted to fall between 5.5 to 6.3.

Options: Seaweed products, humic acid, and vitamin B-1 may be added in small quantities.

Organic Hydroponics
The formulas in this section are designed for mediums that drain well such as perlite, coconut fibers, and clay pellets. These formulas will also work fine for soilless mixes such as Sunshine MIx® and Jiffy Mixtm. These formulas have been formulated to give flowering plants all the necessary primary and secondary elements, as well as the trace elements necessary for vigorous growth. No salts will accumulate with the organic ingredients, which will provide a fine tasting smoke. If quality is an issue and so is volume, the following sample formulas are definitely worth a try.

For complete control, cheap and light perlite is recommended for the medium because it does not alter the solution pH and fertilizers do not cling to it. Perlite also allows lots of air to get in the spaces when solution drains through it. However, perlite needs regular irrigation such as a few waterings a day or continuous irrigation. Not for the sake of food necessity, but for the fact that dry perlite sends out a dust. This dust can collect on the top of leaves.

Clay is good medium, but it is heavy and a little expensive. It is negatively charged and will hold some positive ions such as calcium and potassium. All mediums can be flushed with plain water regularly to remove salts.

Materials that alter the pH can be of use to keep the pH down, such as clay. Also, holding some water and nutrients can be good too, especially between feedings when the water is drained from the growing medium.

Vegetative Growth
Any recommended rate from an organic fertilizer manufacturer should work fine, but feeding needs to be more precise during bloom. If chemicals are used during vegetative growth, and organics are used during bloom, nobody will be able to tell the difference from a garden grown only with organics. This is a way to make tasty produce on a skinny budget.

Sample Formulas

Vegetative Growth Formula #1
Use the manufacturer’s recommended rate for Sea Mixtm 3-2-2, or two-thirds of the recommended rate for Alaska Fish Fertilizer®, combined with the recommended rate for liquid kelp. In addition, pH up or pH down can be added until the ph is between 6.0 and 6.5.
Adding Epsom salts (magnesium sulphate), 1/2 to 1-teaspoon per 5 gallons will help combat magnesium and sulphur deficiencies.
Special note: all pH testing and addition of a ph up or ph down is optional, although recommended. Hydrogen peroxide usage at 1 to 3 ml per gallon is recommended to keep the medium clean.

Vegetative Growth Formula #2
When it comes time for the second feeding, the fertilizing can be repeated. Below is an optional solution to use:
Sea Mixtm, two-thirds of the manufacturer’s recommended rate; humic acid (made from organic molecules created from the breakdown of organic matter) at one-half to two-thirds of the recommended rate; pH up or pH down until the pH hits 6.0 to 6.5.

Vegetative Growth Improvisation Formulas #3
Since the pH of a water supply varies from town to town and city to city, it is possible to use different organic fertilizers to balance the pH. To lower the water’s pH, one custom formula is to make a tea with worm castings and add fish emulsion or Earth Juice®. To raise pH in the water, going a little heavier on the wood ashes is an option. There are many other organic fertilizers with varying ph readings.
A tea of composted steer manure and liquid kelp can be good for a near-neutral water supply.
Every organic fertilizer will alter the pH of a solution to a different degree.

Flowering
A grower can apply any commercial fertilizer and mix it at the recommended rate. Results will be fine. But, in order to grow specific plants productively and with the lowest cost, making custom formulations is the way to go. All large-scale farms know the importance of making their own fertilizers, which is a major expense once the farm is set up.
During flowering, a grower cannot afford to be sloppy. Feeding is more critical and plants use more nutrients when they are producing flowers.

Sample Formulas
Bloom Formula #1
1. Four teaspoons per gallon of Earth Juice®Bloom.
2. Four teaspoons per gallon of Earth Juice®Grow.
3. Four teaspoons of bat guano per gallon. Guano should be placed into a teabag or added directly into the tank. Bat guano can cause stomach aches when it is used in a recirculating hydroponic system, even with minimal exposure. Using the replacement (potassium phosphate) from the chemical cheat sheet (below) is safer than bat guano. Organically, using more Greenfire®Earth Juice Bloom is another option.
4. Growth Plus (Nitrozyme®) at 1/2-teaspoon per gallon.
5. Epsom salts (magnesium sulphate) at .5 to 1 gram per quart (liter). Epsom salts should be dissolved in warm water before adding to nutrient solution.
6. One gram per gallon of sulphate of potash (potassium sulphate) or 2 grams per quart (liter) of wood ashes. Sulphate of potash should be mixed separately in hot water for it to completely dissolve.
7. Finally, pH is adjusted 5.5 to 6.5 with natural pH up or natural pH down.

Options
A grower can add the following to the above formula before adjusting pH.
1. Humic acid at 1-teaspoon per gallon or at 1/4 to 1/3 the recommended rate.
2. For other trace minerals, a grower can add half to full recommended rate of liquid kelp.
3. Adding 1 tablespoon of molasses and two teaspoons of yeast into 1 quart (liter) is a cheap homemade catalyst. The mixture should be dissolved before it is added to the tank. It will add enzymes and help to combat upward pH drift.
4. The solution should sit one or two nights so that pH stabilizes. Running a pump in the solution can help keep the solution agitated. Sometimes, some of the materials, such as bat guano, will flow to the bottom, but most of this formula will stay nicely mixed.
The pH of this solution will drift less upward, the longer it sits in the nutrient tank.
5. pH should be monitored daily and adjusted to 5.5 to 6.5, using either a natural pH up or a natural pH down. Adjusting the formula to a lower pH is a good way to deal with upward pH drift.

Chemical Cheat Sheet
Use .5 to 1 gram of calcium nitrate instead of Earth Juice®Grow and Earth Juice ®Bloom; use chelated trace minerals (1/2-teaspoon for every 5 gallons) while canceling the usage of Growth Plustm (Nitrozyme®) and Pyro Claytm; use potassium phosphate at 1/2 to 3/4 gram per quart (liter) while eliminating the bat guano. The potassium levels can be changed during various stages of bloom to accommodate phosphorous levels.

Bloom Formula #2
1. Four grams per quart (liter) of Pure Earthworm castings. Worm castings can be wrapped in panty hose, a teabag, or cheesecloth. Squeezing the castings in the bag periodically helps to release the fertilizer more quickly.
2. Four teaspoons per gallon of Earth Juice®Bloom .
3. Four teaspoons of bat guano per gallon. Guano can be put in a teabag or panty hose. Guano should be squeezed periodically to release the fertilizer. Bat guano can cause stomachaches when it is used in a recirculating hydroponic system, even with minimal exposure. Using the replacement (potassium phosphate) from the chemical cheat sheet is safer than bat guano. Organically, using more Greenfire®Earth Juice Bloom (recommended rate) is another choice.
4. Growth Plustm (Nitrozyme®) at 1-teaspoon per gallon.
5. Epsom salts (magnesium sulphate) at .5 to 1 gram per quart (liter). Epsom salts should be dissolved in warm water before adding them to a nutrient solution.
6. One gram per gallon of sulphate of potash (Potassium Sulphate) or 2 grams per quart (liter) of wood ashes. Sulphate of potash should be mixed separately in hot water to completely dissolve the crystals before adding them to the nutrient solution.
7. The pH should be checked daily and adjusted to 5.5 to 6.5. A lower number is better for an upward drifting pH.

Options
1. Pyro Clay can be added at 1 gram per liter.
2. Humic acid can be added at 1-teaspoon per gallon or at 1/4 to 1/3 the recommended rate.
3. For other trace minerals, half to full recommended rate of liquid kelp may be added.
4. Adding 1 tablespoon of molasses and 2 teaspoons of yeast into 1 quart (liter) works as a catalyst. The mixture should be dissolved before it is added to the tank. The mixture will add enzymes and help combat upward pH drift.

Chemical Cheat Sheet
Use .5 to 1 gram of calcium nitrate instead of Earth Juice®Grow and Earth Juice ®Bloom; use chelated trace minerals (1/2-teaspoon for every 5 gallons) while canceling the usage of Growth Plustm (Nitrozyme®) and Pyro Claytm; use potassium phosphate at 1/2 to 3/4 gram per quart (liter) while eliminating the bat guano. The potassium levels can be changed during various stages of bloom to accommodate phosphorous levels.

Special Notes (for All Organic Hydroponic Formulas)
Solution should be topped up regularly (i.e. daily to weekly) with plain water or nutrient solution, depending on how the pH, PPM, and water level changes.
The pH of the solution should be checked and modified after adding liquid to reservoir. Drawing a top-up line in the reservoir with a permanent felt-tip pen helps to make topping-up the reservoir a brainless exercise. Large reservoirs that can run a few days to a week with proper pH and PPM make things even more brainless.

These organic formulas on pages 97 to 101 should be somewhere near 1,500PPM when read on a TDS meter after they are mixed, if the water supply reads at 0PPM. A PPM meter can be used as a reference meter. A grower should take readings once in a while and see if the PPM goes up or down.
If the PPM stays the same or goes down just slightly, adding the regular mixed solution to the reservoir should suffice.

Making a solution that keeps a constant PPM (or slightly lowering PPM) gives the plant the exact elements they need until the reservoir becomes empty and is pH buffered: this is the path to feeding perfection. With this method, the reservoir is easy to clean before adding new solution. This is efficient gardening.

If the PPM goes up, more water should be added to the tank to dilute the solution. With this approach, complete changes of solution are recommended, especially for larger plants that use up more nutrient than water.

After a couple of weeks, an organic hydroponic solution can bring on odors, depending on the fertilizer (e.g. stinky bat guano).

If a PPM meter is used in an organic or chemical-organic garden, what works is changing the solution when the PPM drops to 1/3 to 1/2 of the original strength (i.e. PPM drops from 1,500 to 500 to 750PPM). The waste can be poured out anywhere in an outdoor garden. Or, addition of the same formula can be added from time to time to replenish nutrients, if there is no smell. Or, for the trained eye, individual nutrients can be added such as Earth Juice® Grow, bat guano, etc., as deficiencies are spotted.

Nitrogen consumption is probably the heaviest from all the elements in the formulations. Changing the solution and replenishing all nutrients is the best move to keep things simple.

Optional: Foliar Feeding
Note: All pH testing and addition of pH up is optional. The results will still be beneficial if the wetting agent is left out of the recipe.
Foliar feeding should be stopped 2 to 3 weeks prior to harvest so that all residues are rinsed off, and so that nutrients have time to be flushed out of the plant tissue. Flushing allows for top quality. To protect the lungs, a respirator should be worn while foliar feeding.

Formula A
1. 1/3-teaspoon or 3ml of Nitrozyme®(Growth Plustm) per quart (liter) of water, or any liquid kelp used at recommended rate for foliar feeding.
2. 1/16-teaspoon or .25ml vitamin B1 per quart (liter) of water.
3. Organic wetting agent (manufacturer’s recommended rate).
4. Optional: pH up or pH down (to bring the pH to 6 to 6.5 after adding the above ingredients).

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