Page 15 - Griffin Gazette Issue 1 - 2020
P. 15
By Tami Van Gaal, CEA Division Leader
Different growers have different philosophies when it comes to
crop irrigation. Some growers tend to be wet, while others tend to
be dry. Some swear by leaching with every irrigation, others reject
this practice as wasteful. Cannabis and hemp do require careful
irrigation practices due to the limited availability of crop protection
products that can be used to treat root diseases. However, use
of sound, horticultural practices for crop irrigation will keep
roots healthy.
AVOID OVERWATERING!
Overwatering does not mean delivering an excessive amount of water during
a single irrigation event. Overwatering happens when water is applied too
frequently. Roots need oxygen. When the media remains saturated for too long,
the roots don’t get enough oxygen. No part of the pot should still be saturated
at an irrigation event. The best way to avoid overwatering is to avoid the use of
oversized pots with small plants.
APPLY WATER TO IRRIGATE THE ROOT ZONE
When irrigating young crops with roots that do not yet fill the pot, irrigate to
moisten the root zone and avoid saturating the entire pot. As the roots fill the
container, increase the irrigation volume to match their growth.
AVOID OVERLY DRY MEDIA
Dry media concentrates fertilizer salts around the active root hairs. The resulting
high salts injury causes cracks and leaks in the root hairs, which increase the risk
of root disease.
QUESTION LEACHING
Leaching has its place in a crop and is the best way to reduce nutrition levels
when the fertility in the pot exceeds the needs of the plant. However, when fertility
programs are well matched to the crop need, regular leaching is not necessary.
Think of it this way: Leaching even a small amount of fertilizer solution out the
bottom of the pot effectively increases your nutrient costs. This leached solution
never enters the roots. Instead, it is literally money down the drain.
Learn more on YouTube!
Click here on these topics to learn more!
General watering practices
Potted crops
Young plants
Water tool selection
Compare water nozzles
GRIFFIN GAZETTE 2020 | 15
