Plant Nutrition: Keep it Simple.

Small plants in test tubes

by Cindy R

Hydroponic cultivation is considered by many to be the superior method of agriculture both on a commercial level and for personal crop production.  Plants are fed their exact nutritional requirements, provided with controlled environmental surroundings and supplied with their precise lighting needs.  Nature could not offer better growing conditions!

The incredible part about hydroponics is.it’s easy!  Or at least it should be.  Over the past decade the insurgence of pseudo-scientific information in the hydroponic industry has become dazzling.  There are additives, boosters and supplements for your nutrition regime.  New liquid tonics or powdered concoctions pop up daily with a promise to increase nutrient uptake, keep roots strong and healthy, accelerate growth and increase flower size and fruit flavour.  There are detoxifiers and leaching solutions and an abundance of other additives that your plants can’t do without. or so the savvy marketing people would have you believe!

The web offers a wealth of ideas on hydroponic growing, each site offering information skewed to the particular products sold by the owner of that domain.  Wading through the labyrinth of information can be mind boggling.

As with anything the consumer must also be savvy and educate themselves about the different products available.  Understanding what a plant actually needs to sustain life is crucial to help sort through the rhetoric.

To understand what growth influencing factors (GIF’s) are to a plant is to understand basic plant physiology.  Any one of these GIF’s plays a big part in continuance of a plant’s life:  Light, potential hydrogen (pH), carbon dioxide (CO2), oxygen (O2), temperature, humidity and nutrition.

Light requirements can be met with natural sunshine or with an artificial light source.  (CO2), (O2), temperature and humidity can all be controlled by the grower. Plants will survive in the same comfort environment as humans so it is not difficult to supply an adequate amount of these GIF’s.  However, supplementation or tighter controls of these GIF’s may optimize growing conditions.

pH is the level of acid or alkalinity of your nutrient, pH 7 being neutral.  The pH level of your nutrition solution determines the plant’s ability to use the food efficiently.  pH is easily maintained at the proper level by a simple litmus paper test and then adjusting as necessary.

In hydroponics plants absorb nutrients through their tiny root hairs.  The roots will only take up as much nutrition as they require.  It is impossible to overfeed in a hydroponic system, however, mixing a solution too high in nutrient levels will result in root dehydration.

All plants require a balance of nitrogen, phosphorous and potassium (N-P-K) and trace elements to grow properly. The other GIF’s influence a plants’ ability of utilize these nutrients adequately.

There are 20 macro and micro-nutrients required for plant growth:

Macronutrients are required in large amounts
Carbon C Component of all organic compounds
Oxygen O Supplied by air & water
Hydrogen H Combines with oxygen to form water
Nitrogen N Part of chlorophyll, amino acids, proteins
Phosphorus P Used in photosynthesis and almost all aspects of growth
Potassium K Activates enzymes, used in formation of sugar and starch
Calcium Ca Used in cell growth and division, part of cell wall
Magnesium Mg Part of chlorophyll, activates enzymes
Sulfur S Part of amino acids and proteins

 

Micronutrients are required in trace amounts
Boron B Affects reproduction
Chlorine Cl Aids in root growth
Copper Cu Used in chlorophyll, activates enzymes
Iron Fe Used in Photosynthesis
Manganese Mn Part of chlorophyll, activates enzymes
Sodium Na Used for water movement
Zinc Zn Part of enzymes, used in auxins
Molybdenum Mo Used in nitrogen fixation
Nickel Ni Liberates Nitrogen
Cobalt Fixates Nitrogen
Silicon Makes tougher cell walls: enhances heat and drought tolerance

Small amounts of these nutrients can be assimilated through healthy soil, however they are quickly depleted rendering the soil void of all life sustaing properties.

In hydroponic cultivation essential nutrients are provided in ideal proportions. The inert  growing medium does not contain any nutrients. Through extensive research conducted in the 1920’s (and much trial and error)  scientists were able to determine a very specific blend of mineral salts that when mixed with water would completely nourish plants. Immersing plant’s roots directly in this solution proved to be very fruitful and lauched the way for modern hydroponic practices.  The refinement of this technique of cultivation has been on-going ever since.

The word hydroponics was derived from the Greek word ‘Hydro’ meaning water and ‘Ponos’ meaning working, literal translation, water-working.  Today’s definition of hydroponics is ‘soilles cultivation’ which means simply, growing without soil.

The simplicity of hydroponics has been vastly understated.  It is easy to grow almost anything hydroponically. Our North American society insists on complicating things.   Sure there is a benefit to using some of the additives and supplements available to enhance crop production.  But, if you are just starting out it may be wise to keep things as basic as possible. Hydroponic windowsill gardens are available and ideal for planting low light plants.  Fresh herbs can be grown in a kitchen window ready for use in any recipe.  A small 4′ x 4′ garden can be easily maintained and will yield a profusion of crops.

Nutrition is an intregal part of good crop health and a successful yield.  Start off very basic using a high quality concentrate nutrient.  Any reputable hydroponic shop will be able to advise you on which product to choose.  Most nutrient formulas are 2 or 3 part.  This is because these fertilizers contain mineral salts which, when mixed together in a concentrated form will bind together causing them to fall out of suspension.  Follow the manufactures instructions carefully and only mix each part into the water.

Hydroponic formulations are structured for the different stages of growth.  A plant’s nutritional requirements shift from their vegetative stage to their flowering stage therefore, there is a grow formula and a bloom formula.

Plants need higher levels of nitrogen during their vegetative cycle.  Nitrogen is the key mineral in the healthy development of leaves and stems. It is also the most common deficieny in plant growth resulting in stunted growth and yellowing leaves.  During the flowering cycle the ratio of nitrogen to phosphorous and potassium is decreased.

Following a good nutrient regime should be enough to produce a high quality, vitamin rich food source.  Keeping it simple means less troubleshooting should a problem occur. Creating a toxic soup of addivtives and supplements makes it very difficult to find the culprit if something does go wrong.

The more advanced growers may wish to fine tune plant nutrition by supplementing the twenty mineral elements required for plant growth (and contained in good quality hydroponic nutrients). Natural hormones, vitamins and some rare trace elements will stimulate normal biological functions in plants.  There are other products designed to help facilitate faster nutrient uptake and accelerate stem and leaf growth. Discuss the various options with your hydroponic retailer and, if it sounds too good to be true.well, you know the rest!

Great care should be taken when using these growth boosters.  Only introduce one new product per crop rotation.  Try not to get carried away by the promise of bumper crops that are ready to harvest in half the regular time.

Bloom fortifiers are useful to supplement flowering and increase essential oils in plants. Look for a fortifier with a NPK ratio of 0-50-30.  This indicates that there is no nitrogen and very high levels of phosphorous and potassium.  Both of these essential minerals increase the development of super blooms.

Organic gardening practices have become very popular over the last decade.  The hydroponic industry has made great strides in developing organic formulas that will work well in a hydroponic system. An organically based nutrient should be a soluble, stand-alone product that has no sediment on the bottom of its container.  Be wary of organic formulas that require shaking before use.  This could be an indication that the product contains sediment that will clog lines and pumps used in a hydroponic garden.  Never attempt to use an organic fertilizer that is designed for soil applications in hydroponics as it may result in plants burning and lines getting blocked.

Kelp is very safe and an excellent source of organic trace minerals.  Used regularly as a foliar spray, kelp is great way to help avoid nutrient deficiencies. Kelp spray will also act as a pest deterrent.

Regular reservoir changes every 7 to 10 days will ensure that fresh nutrients are always available to meet the demands required for healthy growth.  An electro conductivity (EC) meter will help regulate the optimum amount of nutrient required.  Always check pH after the nutrient solution is mixed.

Leaching or rinsing is necessary to wash out any excess salts that remain in the growing medium.  Leach about 1 week prior to harvest.  Run regular tap water or reverse osmosis water through the system following the established feeding times.

It is always wise to keep a journal of your gardening adventures.  This will allow you to repeat successful harvests and avoid duplicating mistakes.  Record information on a daily basis such as:  Species, germination date, nutrient brand and feeding times, pH, EC, leaching date and harvest date.  Don’t forget to record the time and dose of any additives used.

Keep it simple and enjoy the fruits of your labour.  A hydroponic garden can be a fascinating and rewarding hobby year round.

© Copyright 2013 Homegrown Hydroponics, Inc. All rights reserved


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