Page 23 - Griffin Gazette Spring 2017

Tech Shares

Effective Feeding with Fertilizers

By Fred Hulme, Ph.D., ICL Specialty Fertilizers

When excess essential nutrients are used in greenhouse production, water-soluble fertilizers can leach out of the
root zone and become wasted into the environment.

Here are six practical steps to prevent nutrient leaching in your water-soluble program:

1. Product selection - Proper fertilizer selection is critical to success. Adding unnecessary nutrients will not
grow a better crop, but it will increase the likelihood that nutrients will leach.

• Understand the nutrient needs of the plants you are growing.

• Monitor your growing system to understand what nutrient contribution irrigation water and growing media
might make. The Peters® A B+C system will help you select the best fertilizer for your greenhouse.

• Select a fertilizer program that fills in the nutrient gaps and only adds what is missing.

• Select by nutrient content; crop-specific named fertilizers may not always be appropriate in your
growing system.

2. Rate selection - Product bag label rates are generic. There is no universal standard for “medium” or “high”
rates. Bag labels may guide you to a starting point, but there is always room to customize rates for your
variety of plants.

3. Application method - The way a fertilizer is applied matters. Fertilizer that doesn’t make it to the root zone
or on the leaves is likely wasted. Overhead applications of WSF through sprinklers can be highly inefficient.
Depending on plant spacing, up to 75 percent may not even hit a plant. Handwatering can be wasteful; more
than 60 percent of the WSF solution can be lost as the wand is moved from pot to pot. Drip irrigation to the
root zone can certainly reduce waste through run-off if watched carefully.

4. Timing - Timed fertilizer applications at active crop growing periods to maximize uptake.

5. Irrigation - Nutrients in the root zone move with water. Excess water will move nutrients out of the pot and
be wasted.

6. Systems - Special systems can be employed to better conserve nutrients. If it is not always possible to apply
nutrients efficiently, contained systems such as flood floors or water/nutrient capture and recycle layouts can
protect the environment and save money.

Contact your Griffin sales representative for more information.

TECH SHARES