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Keeping Your Grow Juice Happy

mad scientist

   Hydroponic Fertilizer
   Shortcuts to Reservoir Maintenance

I know we promised to keep things simple, but a little bit of science is in order here. Understanding what hydroponic fertilizer solutions are made of will help you become a better urban farmer!

[If you missed the page on water quality, read that first. We'll wait right here for you.]

First, some basic information on hydroponic nutrients.

Later, we give you some really neat tips and tricks to make reservoir maintenance a snap! So stay with us for the good stuff.

Here's your mini chemistry lesson for the day:

In hydroponics, you take soil away from the plant, so you must supply perfectly
balanced and complete nutrition for it. just remember, plants do not need soil… they need nutrients.

NPK numbers on bag of fertilizer

Plants need large amounts of 6 macro-nutrients: Nitrogen (N), Phosphorus
(P), and Potassium (K). The NPK numbers you see on a manure or fertilizer bag
(like 30-10-30) are simply telling you at what ratio these three macro-nutrients
are mixed in that bag of fertilizer. The other 3 macros are calcium, sulfur and
magnesium. All 6 are provided in the proper ratio in all hydroponics solutions.

Plants also need micro-nutrients (minute traces of other elements) in order to
thrive, just like you do. The nutrient solutions you buy for your 'ponics garden
are different from ordinary plant fertilizers. They include all the trace
elements, too.

So hydroponic fertilizer is kinda like your One-A-Day Vitamins;
it contains the major necessary elements as well as traces of iron, boron, manganese, zinc, molybdenum, copper, cobalt,
chlorine, selenium and silicon. Yum!

test tube baby


Part 2 of your chemistry lesson (and this is important to make hydroponics work):

Remember pH from chemistry or biology class? All pH is is a number that
tells how acid or alkaline your solution is. This is important, because
if the pH is not in the proper range, hydroponic fertilizer nutrients get "locked out" and the plant
can't get to them.

Luckily, pH is a very easy thing to control. All you need is a pH test kit (like
for swimming pools), or pH "dip" strips. Both testing methods are inexpensive
and very easy to learn. You do NOT need to buy an expensive electronic pH meter.

The proper range of pH for your nutrient solution: 5.5-6.5 (6.0 is ideal).


When to test pH:

  • When you mix up a new batch of grow
    Let it settle for a couple hours. Then test and adjust the pH.
    Let set an hour and test the pH again...
  • Twice a week thereafter. If you are
    a worrier, test your hydroponic solution daily. It only costs a few drops of test solution.

How to adjust the pH:

  • Buy a "pH up & pH down" kit.
    Follow the directions on the bottle. A little bit goes a long way, so be
    careful. You'll soon figure out how much is about right.

  • In a pinch
    (if you run out of the kit solution), you can
    fix the pH with these "home remedies". White vinegar will lower the ph;
    baking soda raises it. But these agents are not stable and buffered, and
    should not be used in the long run.

GH pH control kit

Do yourself a favor: Get this kit put
out by GH (General Hydroponics). It includes the test kit plus a bottle each of
pH up & pH down. It costs about $15 and will get you through many gardens. Piece
of cake. Get one here: pH Control Kit

   Which hydroponic fertilizer mix is best?

Here's some solid and simple advice about hydroponic solutions:

  • Only buy solution formulated specifically
    for hydroponics. Regular fertilizer or Hyponex will kill your garden.
  • Buy the best quality nutrients you can. It
    makes a difference, and a little bit goes a long way. Don't put together a
    cadillac growing unit, then try to economize by using cheap nutrients.
    You'll be crying in your onions!
  • Do not buy "organic" nutrients. Organics
    require decomposition (composting) which creates inconsistency in the
    solution and your results; something you are trying to eliminate. "Organic"
    sounds good... but it's not... not for beginning hydro. Maybe a project for later, when you're more
  • One-part solutions are simple and easy,
    but are not flexible. Two-part and three-part solutions allow customization
    and experimentation, and give better results.
hydroponic nutrient solution

K.I.S.S.: Use the same nutrient
solution that NASA does, the best: General Hydroponics (GH) Flora Series
Nutrients. And forget the mixing charts on the bottles. We've figured it all
out for you in the next section, 

The Reservoir
. We also provide some links for ordering this superior
nutrient system on that page.

   Mixing and Maintaining the Reservoir

hydroponics reservoir

miss this practical "how-to" lesson on reservoir maintenance
Talk about Hydroponics Simplified...


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