Recommended Equipment:

A nutrient solution system: I recommend starting with General Hydroponics Flora Series Performance Pack, consisting of the main three liquid parts, several enhancements, and the pH test kit. (Handy tip: If you ask General Hydroponics or other nutrient solution vendors for samples of their products, you can usually get free or discounted trial sizes.) A word of caution about miracle growing fertilizers, do not add any fertilizers other than those you know to be hydro-friendly, as it can cause a nutrient build-up harming your plants.

The nutrient solution water level of the hydroponic container system must be monitored.



As the nutrient solution level decreases it needs to be replenished with fresh water, otherwise the nutrient solution becomes more concentrated and some plants won’t respond well. Add fresh water to bring the concentration back to the level it was when started, often referred to as “topping-off.” The pH of water is an important measurement whether you are gardening indoors or outdoors, soil or soil-less, because it affects whether a plant can properly take in nutrients. The electrical conductivity (EC) of water estimates the total amount of solids dissolved in water -TDS, (Total Dissolved Solids). TDS is often measured in ppm (parts per million). In hydroponics, this measurement is used to determine the approximate concentration of nutrient solution to water.

There is no need to adjust your pH or EC until it is necessary.

There is a lot of misinformation out there about keeping the pH and EC regulated. If I were paranoid, I’d say it was a conspiracy from hydroponics manufacturers and retailers who want to sell more consumable product. Don’t get me wrong, proper pH and EC is important, even critical, to the success of a plant.

I recommend a handheld pH tester such as the Oakton EcoTestr pH 2 Waterproof pH Tester, which is excellent for the home gardener and has been proven time and again to be accurate. There are many hand-held EC devices available as well and if you are checking the pH, it’s a great time to check the E.C.

When do I need to adjust the pH?

Only under the following conditions:

pH is at or below 5.0 or above 6.5

AFTER at least 30 minutes from the time of topping-off or changing the nutrient solution.

How to adjust?

I highly recommend using pH Up and pH Down from General Hydroponics sparingly and only when necessary.

Flushing

Flushing means to literally flush empty the nutrient solution from the hydroponics system and replace it with fresh “good” tap-water. Then return the nutrient solution back to what it should be for the phase of growth. When in doubt, flush the system and refresh the nutrients. Otherwise, it’s recommended to flush your recirculating system every 7 – 14 days. When I grow, I try to keep the nutrient solution working as long as possible, however, salts build-up over time and it is good to flush with fresh water from time to time.