FLUSHING WITH OR WITHOUT PLANTS
If you notice plants in your hydro system are starting to look
sickly or show signs of stress, you may be tempted to try
and flush your system while your plants are still in it. Your
plant leaves may be curling, getting brown spots, or if you
accidentally add too much of a particular nutrient or are
noticing some algae in your water — but your plants still look
otherwise unaffected — it may be time to do an unscheduled
flush. This can be done while your plants are still growing
in the system if done carefully. Do not try to use any flushing
agents not approved for use with plants if you are leaving
your plants in place during a flush. The plants will absorb
the chemicals and at best will kill them. At worse, it won’t kill
them, but the plants will have absorbed the chemicals and
the end consumer will end up eating them. If flushing with
plants in your hydro system is the best course of action, there
are a couple of options.
Hydrogen peroxide can be used in a hydro system to increase
the sanitation level and will not harm the plants. Hydrogen
peroxide will help the plant by providing additional oxygen
to the roots. This is true so long as the amount used is not
excessive. Start with food-grade hydrogen peroxide which
is usually in a 35 per cent concentration. Dilute this with
10 to 12 parts deionized, RO, or distilled water to reduce the
concentration to about three per cent hydrogen peroxide.
Add one to two teaspoons (five to 10 milliliters) of the diluted
solution per each gallon (four liters) of water in your system.
Adding vinegar is another possibility, but this can be tricky if
care is not exercised. Vinegar will lower your pH, so keep that
in mind, but it won’t harm your plants if diluted enough. Dilute
white vinegar down to a similar ratio of the hydrogen peroxide
of one to two teaspoons (five to 10 milliliters) per gallon of
water. Be prepared to adjust the pH accordingly, though.
“HYDROGEN
PEROXIDE
can be used in a hydro
system to increase the
sanitation level and will
not harm the plants.”
26
Maximum Yield
FLUSHING SALT AND NUTRIENTS FROM SOIL
Flushing is sometimes a necessary step in soil culture too.
If salts have built up or the plant has received an overdose
of nutrients, it can often be saved with a flushing of clean
water if caught and acted upon in time. A volume of water
at least three times the volume of the container is recom-
mended to try and leach out the unwanted nutrients or other
foreign substances. Plants grown in soil culture that do not
get flushed when salts build up are prone to root rot or other
diseases that will kill the plant or affect the yields.
Some growers flush their soil-grown crops as a matter of
course during the last couple weeks of the plant’s bloom
so that it will be sure to use up all its stored nutrients.
They cut off the fertilizer supply or switch the irrigation to
water only so that it cannot get any additional nutrients
and will be forced to invade its stores. It is important to use
pH-appropriate water during this phase, so plants can be
sure to absorb all those available nutrients. Water with pH
that is too high or too low can make the present nutrients
unavailable to the plant even if the nutrients are there in
sufficient amounts. If growing hydroponically and the grower
wishes to do this, nutrients should be withheld for only the
last couple of days pre-harvest.
In between crop cycles, the choice to use agents is up to each
individual grower. In nature, the cycle of water flow usually
does an adequate job of keeping things clean. A growroom
or a hydroponic set-up is not exactly the spitting image of
a diverse, thriving ecosystem. Cleaning agents such as
bleach, hydrogen peroxide, vinegar, or any other number of
commercially formulated agents will do a more thorough job
of sterilizing your equipment and increasing its useful life.