Hydroponics for the Home Grower - Grow...

Hydroponics for the Home Grower12 November 2016

Presented by:

Wynand Bezuidenhout(Prof Cert Eng./Owner Grow Machines)

• Hydroponics

• Hydroponic categories

• Hydroponic techniques

• Basics of hydroponics

• Safety

• Instrumentation

• Chemicals

Content

Basics of hydroponics

If you know this…the rest is easy

Hydroponics?

Hydroponics is a method of growing plants without soil, using mineral

nutrient solutions dissolved in water.

Why is Hydroponics important?

Year

Why is Hydroponics important?

Will the less developed people produce food for the less developed regions?It is estimated that by 2050, 70% of all food will be produced hydroponically

Hydroponics is used for

Production of:• Veggies• Herbs• Flowers• Fodders and feeds• Biofuels (Algae)• Electricity• Fertilizers• Super foods (Spirulina, Maringa trees)• Medicines• Sweeteners (Stevia)• Drugs (Marijuana and Poppy's)• Fish food production• Fish production when combined with aquaponics

It comes in many forms!

Moss table generating electricity

Moss Votaics

Hydroponics in bags

Hydroponics in straw

Vertical Tower Hydroponics

Multi row Vertical Hydroponics

A Frame NFT Hydroponics

Deep flow Hydroponics

Raised Bed NFT Hydroponics

Hallelujah Systems

NFT Trellis Crop Systems

Rotary Gardens

Raceway systems

Fodder systems

Did you know?

No matter which system you use, the basics stays the same!

Understanding the basics is the first very important step!

Lets focus on understanding the basics of Hydroponics!

Hydroponics Categories

Hydroponics is a method of growing plants without soil, using mineral

nutrient solutions dissolved in water.

Medium basedMedium free

(Soilless)

Hydroponics (Medium Based)

Rockwool

Stone

Expanded Clay Coco Coir

Wood shavings Coco Chips

Vermiculite Perlite Coco Fibre

Hydroponics (Medium Based)

Advantages:

1. Moisture reservoir

2. Plants can anchor themselves

Disadvantages:

1. Nutrient imbalance over time (buildup of nutrients)

2. Most mediums can only be used once

3. To use it twice – washing and sterilizing is essential. Not

recommended to use any organic medium twice (fungus and

diseases)

4. Costly (buy, transport, discard)

You almost always need mediums to make your seedlings.

Medium free hydroponics is the way of the future!

Hydroponics (Medium Free)

On earth!

And in space!



As the name suggest: No Medium is used except in making the

seedlings

In some case you don’t even need to use medium for seedlings…as

long as you can simulate nature

Magic Spinach (Grown from seed to

harvest in just water with nutrients)


Lets have a look at a few

Medium Free Hydroponic Techniques


Nutrient Film Technique (NFT)

Is a hydroponic technique wherein a very shallow stream of water containing all the dissolved nutrients required for plant growth is re-circulated past the bare roots of plants in a watertight gully, also known as channels. A wide range of cultivars can now be grown in these systems. Not (yet) suitable for root crops.

https://en.wikipedia.org/wiki/Hydroponics

https://en.wikipedia.org/wiki/Nutrients

https://en.wikipedia.org/wiki/Root


Deep water culture (DWC) is a hydroponic method of plant production by means of suspending the plant roots in a nutrient solution of nutrient-rich, oxygenated water. It is mostly used for leafy crops.

Deep Water Culture Systems

(DWC)

https://en.wikipedia.org/wiki/Hydroponic

Hydroponics (Medium Free Types)

Aeroponics (AP)

Aeroponics is the process of growing plants in an air or mist environment. Almost any plant can be grown with aeroponics.

https://en.wikipedia.org/wiki/Plants

https://en.wikipedia.org/wiki/Air

https://en.wikipedia.org/wiki/Mist

Hydroponics (Medium Free Types)

Ebb & Flow/Flood & Drain

(E&F)

Ebb & Flow hydroponics is essentially a hydroponic technique that simulates the tides of the sea with a high tide(full) and a low tide(empty). It is mostly used for the production of seedlings, cuttings and sprouts.

Which hydroponic system is best?

Personal opinion - depends on the application (seedling or plant) and the

cultivar you intend to grow.

Feature NFT DWC AP E&F

Flexibility (multiple varieties) 7 3 9 6

Dissolved Oxygen 8 4 10 7

Use of water 9 5 9 8

Use of Fertilizers 9 5 9 8

Growth rates 9 8 9 6

Hygiene 9 5 6 6

Simplicity to operate 8 5 3 7

Capital 6 7 3 5

Ease of assembly 7 7 3 5

Ease of cleaning 7 5 2 6

Running cost 8 7 5 6

Score 87 61 68 70

1 bad – 10 good

Aquaponics

Combine aquaculture (raising of fish, snails, crabs etc.) with hydroponics in almost a kind of symbiotic way.

Complex

To maintain an economical balance between plants and fish is very difficult.

Aquaponics (typical scenario)

Aquaponics Cycle (As it is known)

Bio filter

Always sacrifice somewhere (condition of plant or fish)

Bio filter

Add extra nutrients and get results

Aquaponics Cycle (As it works best)

Let the plants use all the water. Rather add fresh water to the fish

Basic principles of hydroponics

What a plant need to grow

Seed

H2O CO2

Sunlight

Balanced Nutrients

Climate

O2

HygieneMicrobesComfort

(Ergonomics)

Available (reserve)

Protection/Health

VentilationSpace

Attention


Seed

H2O CO2

Sunlight

Balanced Nutrients

Climate

O2


(Ergonomics)

Available (reserve)

Protection

VentilationSpace

Attention


Nutrients

Mineral elements that a plant need to grow

Nutrients?

• Balanced • Available

Keywords

Nutrients

+ System Design

• Balanced • Available

Keywords

Formulation of the elements

Balanced Nutrients

Means making all the nutrient that plants need available to them in the right blend (like a recipe)• We give them more than what they need….in solution strength.• Plants will only take what they need.• By having a balanced blend we

• Reduce (extend) the risk of concentration or shortage of some of the elements

• Optimize the use of fertilizers

Essential NutrientsBeneficial Nutrients

Free Elements

Making Nutrients available to Plants

Done in two ways:

• Through system design • it must be available in the water and the water must be available to

the plants

• pH Management of the nutrient solution

Aeroponic system

What is pH?

pH is a measure of acidity or basicity of a solution

Why is pH so important?

Because pH determines a plants ability to absorb the nutrients.• At certain pH values there is no maximum absorption and at others there

are no absorption.

“It does not matter how balanced or how available nutrients are to plants…if the pH is not within range, plants will grow little to nothing”

How pH affect nutrient absorption

Nitrogen (N)

4 5 6 8 9 107

Zero absorbance of nitrogen

Maximum absorbance of nitrogen

Ideal absorbance

Absorbance increase Absorbance decline

How pH affect nutrient absorption

Critical range

Survivable range

Survivable range

Micro Nutrient Deficiency

Macro Nutrient Deficiency

Optimal range

How to manage pH

You can not manage if you cannot measure!

pH is measured with a pH tester

pH testers should be regularly calibrated because they loose their calibration over time. Use pH 7.01 and pH 4.01 calibrations solutions.

Transfer solutions into smaller containers for calibration. This prevents cross contamination and save you on solution cost. Calibrate maximum up to five times with solution.

Only use plastic containers for measurements and calibrations. Glass containers will damage the pH bulb of the instrument. Mark the bottles.

Use storage solution to keep the pH bulb wet during storage.

How to adjust pH

Adjust pH down

4 5 6 8 9 107

add

Phosphoric acid Nitric Acid

Adjust pH up

Bicarbonate of sodaWater

How not to adjust pH

Never use!

Pool acid (Chorine) Battery acid (Sulphur)

Caustic Soda (Sodium)

Take caution when using chemicals

Nitric Acid fumes are extremely dangerous and can kill you if inhaled!

Acids are corrosive and will harm you if you are exposed to it.

Keep acids and other chemicals out of reach from children and uninformed people. Please do not use squeeze (Powerade type) bottles to store these chemical as small children can easily mistake it as soda or water.

Use the correct personal protective equipment (vapor type respirators, rubber gloves, safety glasses, rain suit, rubber boots etc.) when working with chemicals.

Always mark your containers to warn others

Have running water available when mixing. If exposed to chemicals, wash it off immediately.

How acids react with water

All water sources reacts different to acids. One can not exactly predict how your water source will react, but you can test it and draw up a reaction graph.

ml Phosphoric Acid added

pH

pH Adjustment of a 1000 liter water body (borehole water with high calcium)

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1

2

3

4

5

6

7

8

9

0 50 100 150 200 250 300

Critical line

pH Stable

pH Unstable

Your water is different!

All water sources reacts different to acids. One can not exactly predict how your water source will react, but you can test it and draw up a reaction graph.


pH


0

1

2

3

4

5

6

7

8

9

0 50 100 150 200 250 300

Critical line

pH Stable

pH Unstable

How much acid is required

Exercise 1: We have a pH of 7.5. We need 6.5. How much phosphoric acid is required on 1000 liter water?


pH


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3

4

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6

7

8

9

0 50 100 150 200 250 300




pH


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9

0 50 100 150 200 250 300

95 ml required




pH


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0 50 100 150 200 250 300

150 ml required

Important notes on pH

• Know about the critical line…adjust your acid quantities accordingly.• When you need to do pH up adjustments you can simply add more water to

your system to do it.• pH is more important than EC because with an incorrect pH the plants can

not absorb the nutrients or fertilizers.

• pH for plants can almost be compared to the pulse of a Human body. The first thing you should check when a plant get sick is the pH of the water, the medium or the soil. In most cases fixing the pH will solve your plant problems.

• pH is important for any type of plant growing technique (hydroponics, soil and even in your garden)

• Water reaction may vary from summer to winter, especially if you use borehole water.

Nutrients and Fertilizers

Quality hydroponic nutrients (or fertilizers):

1. contains all the elements needed in the correct “balanced” ratios (or recipe)…preventing waste

2. provide plants with a complete “diet” for healthy growth3. is completely water soluble

Essential NutrientsBeneficial NutrientsFree Elements

NPK fertilizers as we know it is not good enough. Hydroponic fertilizers are specialty fertilizers.

Nutrients and Fertilizers

Hydroponic fertilizer comes standard in two forms generally known as Nutrigro and Nutriplex. It is two separated mixtures mainly because these mixtures contains Calcium and Sulphur which react with each other in concentrated form to a product called gypsum (CaSO4)

At the moment South African hydroponic fertilizers are still very generic, but we are working on fertilizers for specialized commercial applications.

Omnia Nutrigro and Nutriplex are generic hydroponic fertilizers and good enough for home growing.

How nutrients are managed (EC)

Electrical Conductivity (EC) is the measure of a solution’s ability to conduct an electrical current. It measures the amount of salts in a solutions. The higher the amount of salts present, the higher the electrical conductivity and the higher the reading.

Fertilizers are mineral salts.

EC is measured in Siemens per centimeter (S/cm)

EC is measured with a EC Meter

Calibrating your EC meter regularly is also important.

Use 1413 uS/cm calibration fluid to calibrate.

Stir gently while measuring to remove air bubbles

Unfortunately we can not determine exactly how much of each mineral we have in the solution but we do get an indication of how much of all we have combined. That is why it is important to have a balanced nutrient solution

How much nutrients are required?

Sensitive Leafy crops (like lettuce) are commercially grown at 1.6 – 1.8 mS/cm to prevent tip burn.

All other crops can be grown at 2.5mS/cm.

Seedlings are made at 1.4 to 1.6mS/cm.

1kg of Nutriplex + 1kg of Nutrigro + 1000 litres water = 2.5mS/cm (variable based on the initial water EC)


0

0,5

1

1,5

2

2,5

3

0 200 400 600 800 1000 1200

Gram Nutrigro & Nutriplex added

EC (

mS/

cm)

Nutrients added to 1000 liter water


0

0,5

1

1,5

2

2,5

3

0 200 400 600 800 1000 1200


EC (

mS/

cm)


Exercise 3: We have an EC of 0.8 mS/cm. We need 2.5mS/cm. How much fertilizer is required per 1000 liter water?

650 gram Nutriplex &650 gram Nutrigro required


0

0,5

1

1,5

2

2,5

3

0 200 400 600 800 1000 1200


EC (

mS/

cm)


If fresh water had an initial EC….add it throughout


0

0,5

1

1,5

2

2,5

3

0 200 400 600 800 1000 1200


EC (

mS/

cm)


If fresh water had an initial EC….add it throughout

Exercise 4: We have an EC of 1 mS/cm. We need 2.5mS/cm. How much fertilizer is required per 1000 liter water?

600 gram Nutriplex &600 gram Nutrigro required

Stick to this graph for simplicity

0

0,5

1

1,5

2

2,5

3

0 200 400 600 800 1000 1200


EC (

mS/

cm)


0

0,5

1

1,5

2

2,5

3

0 200 400 600 800 1000 1200


EC (

mS/

cm)


Exercise 5: We have an EC of 0.8 mS/cm. We need 2.5mS/cm. How much fertilizer is required for 200 liter water?

650 * 200/1000 = 130 gram Nutriplex & Nutrigro required

200 liter water? – Use ratios

Ratios can also be used for pH and EC

Ratios

Lets say our 1000 liter tank is half full and we don’t want to fill more water.

For EC:

We know from the charts that to change the EC from 1 to 2,5 we need 600 gram of each fertilizer.

How much fertilizer do we need for the half tank?

Answer = 500liter/1000litre x 600gram = 300gram

For pH: (see next slide)

How much phosphoric acid do we need to change the half tank pH from 7.5 to 6.5?

Answer = 500liter/1000litre x 95ml = 47.5ml – Always measure pH after adjustments because if you are close to or below the critical line this won’t work.




pH


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2

3

4

5

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7

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9

0 50 100 150 200 250 300

95 ml required

Tips for mixing hydroponic fertilizers

• Mix the fertilizers (Nutrigro and Nutriplex) separately. They will react if they get in contact with each other in concentrated form.

• Use a stirring stick instead of your hands (20mm PVC conduit works well)• First mix Nutriplex in a bucket with water until it is fully dissolved and then

add it to the tank. Stir the solution in the tank well.• Then mix the Nutrigro in the bucket with water until it is fully dissolved and

then add it to the tank. Stir the solution in the tank while adding the second mixture.

• Measure the EC• Measure the pH. (Always measure pH after any adjustment)• The instructions are normally provided on the bags. Read it and follow it,

especially if you intend to use hydroponic fertilizers other than Omnia.

Don’t let other people stand by when you mix fertilizers….it burns like crazy if it gets into your eye….don’t rub your eyes after or during mixing.



Seed

H2O CO2

Sunlight

Balanced Nutrients

Climate

O2


(Ergonomics)

Available (reserve)

Protection

VentilationSpace

Attention

The importance of Oxygen


Photosynthesis

carbon dioxide + water + sunlight = sugar + oxygenleaves (stomata) roots cells leaves

carbohydrates atmosphere

Respiration/Transparation

sugar + oxygen = carbon dioxide + water + energycells roots (< absorbed) vapour survive

evaporative cooling


Natural evaporation is a plants build in mechanism of cooling down itself through evaporative cooling. If the plants can not cool themselves through evaporating water vapour they will enter a state off Heat Stress (Wilting).


Wilting occurs when a plant can not transpire anymore because there is no vapour (water) or energy (oxygen). Heat stress is very severe condition to

plants. Plants seldom recover completely from heat stress.

Facts about Oxygen

• Dissolved oxygen levels in water decrease at 24 degrees Celsius and above.• At this point plants start experiencing difficulty to function properly.• Higher temperature = less oxygen• At 28 to 32 degrees Celsius there is almost zero oxygen left in the water.• With no dissolved oxygen two things happen:

1. Plants can not produce energy and enters a state of Heat Stress.2. Anaerobic organisms (harmful organisms that favor low oxygen conditions)

thrive and attack the plants. This typically cause problems like root rot.

Facts about Oxygen

• Once you have Pathogens present, it is difficult to get rid of them and often require total system clean out.

• If your hydroponic system is not properly designed for hygiene, you will likely never get rid of pathogens.

• Oxygen and hygiene is very closely linked because with plants:

• Unhygienic conditions involve anaerobic (low oxygen) conditions where pathogens thrive.

• Hygienic conditions involve aerobic (high oxygen) conditions where aerobic microbes (that control pathogens) thrive.

How to maintain high Oxygen

Preventative

Keep the water as cool as possible! A properly designed system gives you the best chance of success.Use the correct hydroponic technique

Cure

Cool down the water• Ice • Mechanical cooling (water chillers)• Cooling tower

Hydrogen Peroxide

Aerate• Air pump and air stone• Venturi systems• Mechanical paddling