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Hydroponic Nutrients and Plant Growth Factors

Improper use of fertilizers is the common cause of many plant problems. Inadequate amounts cause weak and under nourished plants while an amount above desired quantities may burn and even kill the plant. Good judgment and decisions are required when a plant grows. Below are guidelines for applying nutrient solutions.

Hydroponic nutrient solutions are normally sold in concentrated forms. They are then added to the water supply with a specific ratio. Ideally, 150-600 parts per million consists a normal concentration of hydroponic solution. Normally sold in two or three parts because direct combination is not possible. Remember to mix nutrients into water first before combining, never combine two nutrients together.

How Much Hydroponic Nutrient Solution?

There are specific proportions for each plant type and phase of its growth. Advances in nutrient solutions have greatly improved the precision of concentration based on a plants growth stage. Hydroponic nutrient solutions are usually sold in “grow” or “growth” formulas for the vegetative phases and “bloom” or “flower” for the flowering phase of the growth cycle. Remember to switch to the bloom formula during the bloom stager to increase yields exponentially and max out your plants capacity.

In poor growing conditions weak nutrients are recommended. Low lighting, overheated gardens, crowding and root bound plants. Weak nutrients are also ideal for newly rooted cuttings and for transporting plants or when they are in the transition of growth cycles.

Normal, healthy plants can be used with regular strength solutions in ideal growing conditions. Increasing nutrient solutions could be utilized to enhance efficiency of your gardens. An ideal system such as high quality lights, proper aeration and ventilation when present is the only instance wherein you could increase the level of nutrient solutions to improve plant growth. Gradually increasing the nutrient solution is advised as not to burn the plant roots.

Various additives are also available for optimum plant growth. Maintain good grow logs or records of types of additives used, when applied and results. This enables you to measure its effectiveness in the future. If there are any negative effects with experimentation, flush or rinse your hydroponic system immediately.

How to measure Hydroponic Nutrient Solutions

Electronic conductivity of dissolved minerals in the water is the usual basis for determining nutrient solution. Parts per million (ppm) is the unit of measure. But this is just a general way of measuring conductivity in the solution and not the actual strength of individual minerals. This is the main reason why hydroponic nutrient solutions are sold as a mix of 3 parts. Once the desired mix is achieved it is very convenient to change the concentration to achieve proper conductivity.

Overuse of Hydroponic Fertilizers

Flushing out your growing medium is the first intervention once any signs of over fertilization are observed this is to prevent further damage to the plant. Clean water is used for flushing until signs of nutrient deficiency are observed in the plant. Normal feeding and schedule is then resumed. Some hydroponic systems require a top down flushing to completely clean out the plant.

pH Testing

Often referred to as the power of Hydrogen. It is the measure of Alkalinity or acidity of solutions based on hydrogen ion content. pH is measured from a scale of 0-14, acids are in the 0-7 bracket (0 the most acidic), and bases at the 7-14 range (14 the strongest). Introduction of nutrients affect the pH of the solution as they activate the hydrogen and hydroxide ions. Constant monitoring is required to ensure proper pH levels are maintained.

Ideal pH for Plant Growth

Different pH levels are recommended for each and every plant. Attention to research should be done to ascertain the proper pH level for your plant. Findings however have found out that a pH level of 5-7 is safe for most plants, 6-6.5 being the most ideal.

Be Careful When Handling Chemicals

Solutions having a pH of between 3 and 10 are usually safe for handling. Caution is advised for solutions outside this range as they would likely be strong acids or bases. Gloves and goggles are advised as a precautionary measure every time you work with any type of chemical.

Controlling pH Level

Checking pH levels should be second nature when nutrients are introduced to your solution. When solutions acid levels are observe to be always high, solutions should be changed more frequently. When nutrients are absorbed by the plant, this action makes the solution acidic and leads to nutrient “lock up.” pH level are signs of nutrient deficiency, be sure to constantly check them. Check your water this may be the cause and not the nutrient solutions.

Various types of pH test kits are available in the market today. Some are fairly accurate with the more expensive one showing an increased degree of accuracy. Litmus paper and liquid pH tests kits used in swimming pools are an inexpensive way of measuring pH. This works for most of the plants, but plants with more sensitive pH reactions require more elaborate ph test kits. pH UP and pH DOWN chemicals are used to adjust pH levels in your solution.

Plant Growth Factors

Complete freedom from environmental factors gives indoor hydroponic gardening its ultimate advantage. All the elements needed for optimum plant growth are provided by the indoor hydroponic gardening system. Light, temperature, pH, CO2 and Oxygen are important factors that should be considered in planning your indoor hydroponic garden system.

Light and Photosynthesis

Essential sugars are created by plants through photosynthesis which is the process of converting carbon dioxide, water and nutrients into energy. Light is considered the most important factor because it provides energy for this chemical reaction. Studies show that an increase in light intensity directly increases the amount of sugar produced. This steadily goes up till the saturation point for light is reached by the plant. Increasing the level of light received by the plant should also be considered. Normally, a plant receives around 8-12 hours of sunlight in a day depending on the season. Plant exposure to this amount of light received in a day should be maintained in an indoor hydroponic garden system. Spacing is also important, be sure that they don’t block the light and ensure all plants received equal amount of light.

Plants not receiving enough light will have lasting negative effects on its growth even when corrected. Some characteristics are stems which are spindly and elongated leaving them ineffective in supporting plant growth. A decrease in the amount and size of the leaves is also one problem. More damaging effects of improper lighting are a decrease or absence of fruits, decreased overall quality and a change into a yellowish pigmentation for the plant.

Carbon Dioxide also plays a major role in Photosynthesis. Plants utilize the CO2 present in the atmosphere than anything else. CO2 systems are available which increase the levels of CO2 in your indoor hydroponic garden system

Good ventilation should also be considered as they maintain temperature and a steady fresh supply of CO2 and oxygen at all times. Complex setups require more complicated ventilation systems but an oscillating fan set on the same timer as the lights would ensure airflow.

Carbon Dioxide (CO2) Systems

Carbon Dioxide (CO2) as described in the previous paragraphs is one of the most important elements needed for plant growth. CO2 is combined with nutrients, water and energy from light (grow lights/ sunlight) is utilized during photosynthesis producing essential sugars that provide energy for the plant. Any factor missing needed for photosynthesis will limit the plants growth potential. In order for a plant to grow to its utmost potential and for it to yield the best results all of the elements must be present.

Carbon Dioxide (CO2) Injectors

One of the most cost effective way of adding CO2 to an indoor hydroponic garden system is with the use of CO2 injectors. A valve, regulator and gauge are used to measure CO2 levels injected to the air. Sophisticated CO2 injectors are also used to control CO2 release. CO2 tanks are readily available from medical supply outlets and restaurant supply stores.

Carbon Dioxide (CO2) Generators

Investing in CO2 generators would also be wise for long time use in your indoor hydroponic garden systems for several crops. CO2 generators burn propane, natural gas or other carbon based fuels to produce carbon dioxide. More expensive than CO2 tanks, they provide a more convenient way of producing CO2. Long period and continuous use of CO2 generators has proven to be more efficient and economical than purchasing injectors and many tanks.

Carbon Dioxide (CO2) Monitors and Controllers

CO2 monitors with controllers automatically maintain indoor hydroponic garden systems CO2 levels. It is advised for large-scale gardeners or hobbyists and enthusiasts with that extra cash to invest. Often in the hundreds of dollars, they are quite expensive but are really effective if you can afford it. An electronic CO2 monitor together with a CO2 controller are used to maintain CO2 levels. Monitors could be sold separately and can be used with various types of controllers giving room for flexible indoor hydroponic garden designs.


Water quantity requirements vary according to the type of indoor hydroponic garden system. Adequate levels of water should be maintained whatever type of indoor hydroponic garden system used. Water deficiency even if reversed and corrected cause permanent loss in production.

Not only the amount of water but also quality of water is important. Poor quality also causes serious problems for any indoor hydroponic garden system. The use of tap water can affect the nutrient balance in hydroponic solutions. Tap water naturally contains mineral and salts. Often referred to as “hard water,” tap water is offset by constant monitoring and adjusting nutrient solution. Salt content should always be kept below 325 ppm (parts per million) whenever possible.


Temperature is a gauge for optimum production for every plant. When plants are exposed to extreme ranges of temperature, stunted growth and poor fruit yields are the result. Plants have specific temperature ranges for their ideal growth. Warm-season vegetables and most types of flowers have 18o C and 260 C as an ideal temperature range. Cooler season vegetables like lettuces have a 10o C to 18o C range.

Primary Hydroponic Nutrients

Nitrogen (N)

The most essential of all nutrients for leaf and stem development. Nitrogen consumption depends on a plants growth cycle and in a vegetative growth phase of plant nitrogen consumption is greatest. Hydroponic nutrient solutions labeled as “grow” or “flower” contains more concentrations of nitrogen. Nitrogen deficiency is the leading cause of plant growth in indoor hydroponic garden systems. Yellowish, soft and weak plants and leaves are tell-tale signs of nitrogen deficiency.

Half-strength nitrogen solutions are ideal for plants between growing phases. This will prevent plant stretch while it’s switching its energy over to flower development. Normal feeding is resumed once the plant reaches the flowering stage.

Phosphorous (P)

Phosphorous plays a major part in root and flower development. Phosphorous deficiency signs are slow and stunted plant growth. Phosphorous is crucial to a plants flowering stage. “Bloom” type formulas contain a 0-50-30 concentration, containing no nitrogen and high levels of phosphorous and potassium.

Potassium (K)

Different in action from the previous two nutrients, it doesn’t feed the plant directly in any specific stage of growth. It merely facilitates plant intake of other primary and secondary nutrients. Potassium deficiency cause irregular plant growth and susceptibility to pests and disease. Potassium inhibits fruit production and should be lessened during this stage.

Secondary Hydroponic Nutrients

Calcium (Ca)

Facilitating and filtering the absorption of other nutrients Calcium is one essential nutrient. It is also a natural base that increases the pH level is needed. Commonly used in the vegetative phase of plant growth, calcium consumption is decreased during the flowering stage.

Magnesium (Mg)

Mainly for chlorophyll production in photosynthesis, deficiency causes yellow leaves.

Sulfur (S)

Yellow leaves are a sign of sulfur deficiency and are only used in small amounts.

Iron (Fe)

Used in small amounts, iron deficiency is similar to sulfur deficiency. Yellow leaves are the general signs of deficiency. High pH causes iron absorption problems so constant monitoring is advised.

Molybdenum (Mb)

Mainly for nitrogen absorption and converts nitrates to ammonium

Boron (B)

Facilitates carbohydrate transport in the phloem, it is not essential and maybe disregarded. Boron overdose causes plant kill, it is not found in regular soils and only supplemented.

About the Author

My name is guy. I am the founder and owner of the urbangardenershop.com.au . I fell in love with hydroponics gardening. As time went by I gathered a vast knowledge base and 2 years ago I decided to find a way to make hydroponics gardening a hobby that anyone can peruse. I added a hydroponic gardening information center to our hydroponic supplies site that offers a large range of hydroponics articles. Thank you for your interest and feel free to ask questions on hydroponics gardening in our blog


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