REFERENCE SUFFICIENCY RANGES
VEGETABLE CROPS

Tomato, Greenhouse

C. R. Campbell

• Critical Values

  None established.

• Sampling Procedures

  The most recent mature or fully expanded leaf is the best indicator sample for all growth stages. This is generally the 4th or 5th leaf from the growing point.

  Eight to ten leaves are required for a good sample. After drying, the midribs should be removed and discarded.

  Sampling should commence at the first sign of a problem but no less than two weeks before flowering for monitoring. Samples should be taken at weekly intervals.

  Samples are shipped to the laboratory in paper containers.

• Sufficiency Ranges
  
  
  • Most Recent Mature Leaf
    All growth stages
    
    

    Macronutrients
    N	P	K	Ca	Mg	S
    3.5–5.0%	0.30–0.65%	3.5–4.5%	1.0–3.0%	0.35–1.0%	0.2–1.0%

    
    

    Micronutrients
    Fe	Mn	Zn	Cu	B	Mo
    50–300 ppm	25–200 ppm	18–80 ppm	5–35 ppm	30–75 ppm	0.1–1.0 ppm

    
    

    Excessive or Toxic Nutrient Levels

    Boron becomes toxic at approximately 200 ppm and can cause distortion and burn of the growing point. In severe cases, boron tops the plant by injuring the growing point. In such cases, yield is decreased.

    Excess nitrogen is characterized by lengthened internodes and "bullish" growth in the top of the plant. In severe cases, fruit set is adversely affected. The N:K ratio appears to be more important than nitrogen concentration in limiting the effects of high nitrogen. A N:K ratio of 1.2 to 1.8 is desirable.

• DRIS Norms

  DRIS norms have not been reported for greenhouse tomato.

• Remarks

  Sufficiency ranges were developed from available references and experience reviewing analytical results.

• References

  Plank CO. 1989. Plant analysis handbook for Georgia. Athens (GA): University of Georgia Cooperative Extension Service. 64 p.

Electronic Document Prepared by:
Catherine Stokes, Communication Specialist
Agronomic Division of the N.C. Department of Agriculture and Consumer Services. July 2000.