16
ORGANIC SUBSTRATE
The pH measurement of organic substrates is important in greenhouses and nursery growing pots.
pH should be checked at the outset to make sure that the pH of bought substrate is that desired
(pH can change if too much time elapses from the date of packaging to the moment of utilization).
1) Ensure pH meter is set up correctly and pH electrode is calibrated.
2) Direct pot measurements
a) Add a little distilled or deionized water to the substrate if it is dry
b) Use the
HI721319
auger for ground penetration to puncture the soil.
c) Insert the electrode pushing it slightly into the substrate to ensure the pH bulb is in contact
with with it.
d) Allow the measurement to stabilize and record the value.
e) Wash the electrode with tap water and gently remove any substrate remaining on the
electrode with your finger, this will prevent the glass from scratching.
3) Substrate solution
a) Extract a sample of the substrate and allow it to dry. Remove any plant residues and rocks.
b) Weigh 10 g of soil into a beaker and add 20 mL of
HI7051
soil sample preparation
solution. If necessary the sample size can be increased to 20 g and 40 mL of
HI7051
.
c) Mix the sample vigorously for 30 seconds.
d) Wait 5 minutes. This will allow the soil to release soluble nutrients.
e) Immerse the pH electrode into the prepared sample and swirl gently.
f) Allow the measurement to stabilize and record the value.
g) Wash the electrode with tap water and gently remove any soil remaining on the electrode
with your finger, this will prevent the glass from scratching.
ORGANIC SUBSTRA
TE
IRRIGATION WATER
Irrigation water quality is a very important factor. If the pH value is well below pH 7, it is possible
that contaminants are present.
Ranges for evaluation of water quality:
‑ 6 to 8.5 pH: good, can be utilized without problems
‑ 5 to 6 pH or 8.5 to 9 pH: sufficient, sensitive crops could have problems
‑ 4 to 5 pH or 9 to 10 pH: use carefully, avoid use if possible
‑ pH<4 or pH>10: Indicates presence of contaminants. Do not use for irrigation.
IRRIGA
TION W
ATER
