Learn to identify and control aphids
Note: CEU credit is available for this course in some states. Please refer to the information on the CEU Credit Information tab, above, for details.
In this course,...
Learn how Bicarbonates affect soil and plant health
Learn about boron's function in plants, and how to check for (and correct) deficiency and toxicity situations.
Learn about carbon's role in plant growth, and why it's such an important element for all living things.
The following CEU-credited courses are available to myHarrell's customers.
This course covers common nutrient deficiencies in plants.
This course includes a visual guide for identifying nutritional deficiencies of ornamental plants
Welcome to the Downy Mildew on Ornamentals course!
This course will teach you to identify Downy Mildew, and offers advice on prevention.
This course describes how soluble salts impact fertilizers and plants.
Don't forget the roots - they're important for healthy plants
This learning module explains how plants absorb liquid nutrients through their foliage, and how to maximize uptake in your nutritional spray program.
Growers: here's some advice from Lynn Griffith on how to make better decisions on the timing of nutritional sprays.
This course will teach you about fungus gnats and how to control them
One of the most economically destructive plant pathogens in the world