As we move through production for fall and winter crops a refresher for nutrient deficiencies feels appropriate.
No matter where you are in the cropping cycle, nutrition problems can be tricky to figure out. The good thing is they can be differentiated from disease or pest issues based on a few key observations. If the damage is uniform and crop-wide, it's most likely a nutritional issue and if the damage is localized or more random, it's most likely a disease or pest issue.
Early detection of any problem can be achieved with regular monitoring.
Nutrient Mobility:
When deficient, mobile nutrients will move to the new growth, but immobile nutrients will be trapped in the old growth. A quick scan of where the damage is occurring can help to narrow the potential culprits.
Stunted growth:
If plants are looking shorter than normal, crop wide this can be a sign of nitrogen (N) or phosphorus (P) deficiency, especially if the older growth also looks yellowed. Individual or clustered groups of stunted plants are more likely to be caused by diseases.
Interveinal chlorosis:
Dark green leaf veins with light green to yellowed leaf tissue? Sounds like a deficiency in magnesium (Mg), copper (Cu), iron (Fe) or manganese (Mn). Magnesium deficiency should show up in the bottom leaves first since it's a mobile nutrient. Copper, iron, and manganese are immobile, so expect to see the chlorosis in the newest leaves initially. Of course, as the deficiency progresses, all leaves can show symptoms.
Leaf margins:
If a border around the outer edge of a plant's leaf looks yellow, purple, red, or brown it might be a potassium or calcium deficiency. This can also be a sign of pesticide or fungicide phytotoxicity, so review your spray records carefully.
Read more at: onfloriculture.com