Page 23 - Griffin Gazette Issue 3 - 2019

Nutrient deficiencies are best diagnosed with Lower Rates
visual symptoms backed up by media and
tissue analysis at a reputable testing lab. Iron As growers have become more efficient
deficiency is typically the micronutrient that at using water soluble fertilizers, they have
growers focus on when they observe chlorosis decreased the total amount they are routinely
or yellowing on new plant tissue, however applying to reduce waste and save money. As
similar symptoms can be caused by a shortage concentrations drop below 150 ppm N; an
of other micronutrients such as manganese unforeseen consequence of this efficiency is
or copper. that the micronutrient supply can be insufficient.
Adding a very small amount of Liquid STEM (3.5
to 10 ml/ 100 gallons) to the stock tank
Micronutrient deficiencies seem to be more on a constant basis will boost the
common these days. I think this is due to micronutrient supply.
several factors:
• New crop genetics that are inefficient at
taking up micronutrients. Water/ Media Quality
• Growers using lower fertilizer concentrations
(ppm N) or rates that result in an inadequate Maintaining a rootzone pH (5.5 to 6.5) is
micronutrient supply. the best way to guard against micronutrient
deficiencies. Fertilizer selection is critical. It is
• Issues with water quality – excess total best to test your irrigation water first, then select
alkalinity or bicarbonates that increase root a fertilizer based on active and potential acidity.
zone pHs. ICL can help growers work through this process
• Issues with growing media components and – contact your ICL Territory Manager for more
lime charges that lead to high root zone pH. details. If water alkalinity is too high or lime
charge is excessive, highly active fertilizers like
®
®
®
Peters Excel and Peters Excel pHLow can
New Crops reduce and maintain pH at acceptable levels.
These fertilizers can prevent micronutrient
deficiencies by attacking the underlying cause
A young plant supplier should be able to provide
guidance on any special nutrient requirements (high pH).
of new crops added to a production schedule.
ICL has also developed several new water- Rescue
soluble formulations such as Peters 20-3-19
®
Petunia Special and Peters Professional If rootzone pH has increased during production
15-3-25 Flowering Plant Special with black and micronutrient deficiencies have developed,
Iron. These formulations contain elevated iron a rescue treatment is quickly needed to keep a
employing HBED (aka black Iron), the strongest crop salable. If uncertain of the cause, Peters
®
iron chelate on the market - efficacious at very Liquid STEM is a great product to use as
high root zone pHs. These are very good fits for it contains all the micronutrients required.
“iron-hungry” plants.
Oftentimes a crop will be treated with a chelated
New plants with special nutrient requirements iron source when the deficiency issue is caused
may conflict with the needs of other crops by a lack of another micronutrient. In this
grown. These plants may need to be situation, the symptom will not be reversed,
periodically treated with additional drenches of and valuable time wasted. Treating with Peters
®
®
micronutrients. Peters Liquid Stem is a great Liquid STEM will likely supply the micronutrient
product to use for this purpose at a rate of 4 to needed to green up a crop without delay.
8 fl. oz. / 100 gallons. It will supply a complete Another possible rescue is the use of Peters 21-
array of micronutrients in chelated form that 7-7 Acid Hammer – a few applications can boost
are highly soluble and compatible with virtually iron levels and lower rootzone pH significantly.
every fertilizer and even most pesticides.
For more details of the products mentioned
above, go to: https://icl-sf.com/us-en/explore/
ornamental-horticulture/

Image: Micronutrient deficiency symptoms due to low Fe & Mn induced by high rootzone pH. GRIFFIN GAZETTE 2019 | 23