Nutrient and pH
Introduction ~ Why this topic is so Important
pH Values and pH Meters
Nutrient Levels and Nutrient Meters
Automatic Controllers
About Metabolic Enhancers and Supplements
Organic Nutrients
Introduction
If you want your plants to excell, you will want to pay
close attention to the nutrient solution. By monitoring
nutrients, not only can you feed your plants the appropriate
level of nutrition, but you can also maximize the nutrients
available for uptake. Monitoring a solution ensures that
you will not be underfeeding or burning your plants with
too-high levels.
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pH
The pH value of a nutrient solution is a measure of the
acidity or alkalinity of a solution. A basic, neutral
solution is numerically equal to 7. The solution gets
more acidic as the numbers decrease and more alkaline
as the numbers increase. The ph scale ranges from 0 pH
(very acidic) to 14 pH (highly alkaline). Pure water has
a pH of 7, indicating that it is neither alkaline nor
acidic, but neutral.
Different nutrients are absorbed at different pH levels.
Most plants need a pH level between 5.8 and 6.5 for optimum
nutrient uptake. If the pH is too low, nutrients are bound
up and the roots are unable to absorb them. If the pH
is too high, your plants may succumb to toxic salt buildup,
limiting the ability of the roots to intake water and
food.
Your pH will fluctuate and should be monitored regularly.
It can be tested with inexpensive pH papers or with a
pH Shaker Tester, or you may choose to use a pH meter.
pH meters come in various degrees of sophistication and
price. Some are handheld and need to be turned on each
time they are used. They cost less but need more frequent
calibration to keep them reading accurately. Other pH
meters are continuous reading models which are always
on and should be mounted next to the reservoir.
If you want to get real fancy, you can tweak the pH of
your solution to allow more nitrogen in the growth phases
and then readjust during the bloom phase for more phosphorous
uptake. Most importantly you'll want to adjust the pH
of your solution based on what plants you're growing.
pH Values for Different Hydroponic Crops
Plant pH Range
Beans 6.0-6.5
Broccoli 6.0-6.5
Cabbage 6.5-7.5
Cantaloupe 6.5-6.8
Carrots 5.8-6.4
Chives 6.0-6.5
Cucumbers 5.8-6.0
Garlic 6.0-6.5
Lettuce 6.0-6.5
Onions 6.5-7.0
Peas 6.0-6.8
Pineapple 5.0-5.5
Pumpkin 5.0-6.5
Radish 6.0-7.0
Strawberries 5.5-6.5
Tomatoes 5.5-6.5
Adjusting the pH Level
The pH level of your nutrient solution will need to be
adjusted if it is too low (too acidic) or too high (too
basic.) You will want to keep pH Up and pH down handy
in your grow area. Use very little at a time and stir
the solution thoroughly. If you use to much of one then
you will have to correct it with the other. The less you
end up using, the better.
Be careful when handling these solutions as they can
burn the skin.
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Measuring the Nutrient Levels
By monitoring nutrients, not only can you feed your plants
the appropriate level of nutrition, but you can also maximize
the nutrients available for uptake. Equally important,
you can be certain that your plants aren't undernourished.
Both EC & TDS meters give an easy-to-read reference
point of the conductivity of nutrient in solution.
TDS stands for Total Dissolved Solids and is measured
in ppm or parts per million. One ppm is one part by weight
of the mineral in one million parts of solution. I. In
hydroponics TDS is estimated using a converstion from
the measure of electrical conductivity (EC). TDS is currently
the standard of measurement that most US growers use.
This will probably begin to change in the future as hydroponic
manufacturers begin changing their products to EC.
EC stands for Electrical Conductivity and is measured
in mS/cm or miliSiemens per centimeter. An EC meter measures
an electrical current in the solution and reads the conductivity
produced from the motion of the mineral ions.Low conductivity
means low nutrient concentration, often resulting in nutritional
deficiencies and slow plant growth. High conductivity
means more food for your plants. But be careful of not
to get over zealous with the concentration of your nutrient
solution; very high conductivity can burn or kill your
plants
You may choose to monitor your nutrients with a handheld
meter such as the Truncheon. You may also choose to use
a continuous reading model such as the Nutri-Dip.
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Nutrient Controllers
Nutrient controllers have been used for years by the commercial
greenhouse industry, but they have only recently become
available for small scale and hobby growers. Most nutrient
dosers are capable of keeping both nutrient and ph levels
at the correct values.
They are a little expensive, but if you plan on growing
hydroponically for anything length of time, you may want
to consider it. Your plants will greatly benefit because
they will have a perfectly consistent nutrient source
that will allow them to grow strongly without any setbacks.
Your plants will not go for a few days here and a few
days there with low nutrients or an incorrect pH level.
Instead they will have exactly what they need, all the
time.
Nutrient and pH controllers work through the use of set
points and duration doseage times. It's a very simple
concept. You program in the set points you wish for and
the controller will dose the reservoir with a set amount
of nutrient or pH adjuster to bring the reservoir readings
to the right level.
There are two delivery systems that are available for
these controllers. One is gravity fed with the use of
solenoid valves. The second method is with a pump delivery
system which eliminates the restriction on placement.
(In gravity fed systems, the nutrients must be placed
directly above the reservoir.) Both of these methods work
well and once you have become acquainted with the parts
involved, you will find them very easy to use.
There are several nutrient and pH controllers on our
website. They vary in price and quality.
The system that we recommend (and use ourselves) is the
IntelliDose from Autogrow Systems. It's an extremely easy
system to use that controls your nutrient and pH levels
on demand. The system is great for all sizes of gardens
from the small hydroponic garden to a full scale hydroponic
farm. With the IntelliDose you can simply calibrate your
pH twice a month and designate settings, the IntelliDose
does the rest for you.
The professional grower may be interested in the Nutridose
II. This controller is the most industrial of those we
offer and may be used with peristaltic pumps or with solenoid
valves. It also has remote accessing capabilities, but
it is slightly more complicated to use.
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Metabolic Enhancers and Supplements
Although hydroponic formulas have come a very long way
in providing total plant nutrition, many vital compounds
and biological agents that are available to the plant
in healthy soil are absent. When used correctly, metabolic
enhancers can bridge the gap between organic and mineral
nutrition. They can help the achieve full plant potential
at every stage of growth. Metabolic enhancers and supplements
can provide for
Better seed germination
Stronger seedlings
Faster more vigorous clones
Massive root systems
Healthier vegetative growth
Better resistance to pests & disease
Bigger plants, higher yields
Please be aware that many hydroponic supplements are new
and much remains to be learned about the materials involved.
Always be cautious when experimenting, and let us know
your results! We'd love to know how they work for you.
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Organic Nutrients
Many growers want to use organics in their hydroponic
system. Although there are many brands of 'hydro-organic'
nutrient on the market today, these nutrients are a bit
more difficult to manage than 'regular' hydroponic nutrients.
Organic nutrients (such as bat guano or bone meal or solutions
made from these kind of ingredients) must be broken down
before the plant can absorb the minerals. They work great
in soil because of the micro bacteria which increase the
rate of this process. In hydroponics there are no beneficial
'helpers' and so growth can be much slower as nutrients
are not as quickly available to the plants.
Another thing to be wary of with organic nutrients is
their propensity to clog drip emitters, tubing and pumps.
It will be easier to grow organically using an ebb and
flow system (with no drippers) as opposed to a drip system
with many small parts.
Many growers use a regular hydroponic nutrient and supplement
it with organic additives for the best of both worlds.
For an excellent discussion on the organic/hydroponic
debate, check out this article on General Hydroponic's
website
