Table 2. Leaf petiole fresh sap nitrate-nitrogen and potassium testing guidelines for tomato[1].
| . |
Fresh
Petiole Sap Concentration (ppm)
|
|
| Development Stage/Time |
NO3-N
|
K
|
| First buds |
1000-1200
|
3500-4000
|
| First open flowers |
600-800
|
3500-4000
|
| Fruits 1-inch diameter |
400-600
|
3000-3500
|
| Fruits 2-inch diameter |
400-600
|
3000-3500
|
| First harvest |
300-400
|
2500-3000
|
| Second harvest |
200-400
|
2000-2500
|
[1] Adapted from G. Hochmuth, Plant Petiole Sap-testing Guide for Vegetable Crops, Fla. Coop. Ext. Serv. Circ. 1144 (1994).
