Plant Problem Diagnosis Key / Nutrient problems
Nutrient
Too much nitrogen
N excess
More nitrogen than the plant can use makes soft, dark, leafy growth that delays flowering, cuts fruit set and leaves plants more prone to pests.
Signs
- Very dark green leaves.
- Lush, soft growth with few flowers or fruit.
What favors it
Heavy feeding, high-nitrogen fertilizers in fruiting stages, and manure or compost on top of a full feed.
Prevention
- Feed nitrogen to the crop's stage; cut it back once flowering begins in fruiting crops.
- Test soil before adding manure-based amendments every year.
Often confused with
Sources
- Quick guide to fertilizing plantsUniversity of Minnesota Extension
- Fertilizing Vegetable GardensUniversity of Maryland Extension
- Why do the plants get flowers but don't get fruit?Mississippi State University Extension
- Southwest Yard & Garden, August 9, 2014New Mexico State University
Treatment by crop
Cultural, biological and chemical options in the order to use them, and notes written for each crop.
Identification is free. Treatment is on the Home and Pro plans.
Questions in the key that lead here
- Look the plant over, leaf undersides included. Are insects, mites, slugs, eggs, webbing or droppings on it?
No, only damage or discoloration - Where is the problem?
Leaves - What does the leaf damage look like?
Shape change - What has the leaf done?
Leaves very dark, glossy and clawed down at the tips
Not a match? Start the key or describe what you see.
More from university Extension: search Extension pages on too much nitrogen, or find a plant diagnostic lab through your state's Extension.