Excerpt from Melon Research Update 2005pW7

The Grower’s Citrus & Vegetable Magazine
Vance Publishing

 

A way to maximize production efficiency is to monitor nutrient status within the plant during the crop growing season is through the use of Plant Tissue Analysis and/or Petiole Sap Testing. The data contained in the accompanying Tables is a guide to sufficient nutrient status for cucurbits

Plant Tissue Analysis
Plant tissue analysis information for cucurbits at the early bloom stage, using the most recently matured leaf.

N             P             K             Ca           Mg          S             Fe            Mn          Zn           B             Cu           Mo

Status                                                    Percent                                                                                  Parts per million
Cucumber
Deficient            <2.5             0.25         1.6           1.0           0.3           0.3           40            30            20            20            5              0.2

Adequate           2.5-5.0    0.25-0.6    1.6-3.0     1.0-3.5    0.3-0.6    0.3-0.8     40-100     30-100     20-50      20-60       5-10       0.3-0.2
Range

High                     >5.0           0.6           3.0           3.5           0.6           0.8           100          100          50            60            20            2.0

Toxic (>)                                                                                                                                                900          950          150

Cantaloupe
Deficient           <4.0              0.4           5.0           1.0           0.35         0.2           40            20            20            20            5              0.6

Adequate          4.0-5.0      0.4-0.7     5.0-7.0    1.0-2.0    0.35-0.45  0.2-0.8   40-100    20-100     20-60       20-80       5-10       0.6-1.0
Range

 High                   >5.0             0.7           7.0           2.0           0.45         0.8           100          100          60            80            10            1.0

 Toxic (>)                                                                                                                                                900                          150

Pumpkin

Deficient          <3.0               0.3           2.3           0.9           0.35         0.2           40            40            20            25            5              0.3

Adequate       3.0-6.0       0.3-0.5     2.3-4.0     0.9-1.5    0.35-0.60   0.2-0.4    40-100     40-100     20-50       25-40       5-10      0.3-0.5
Range

 High                 >5.0               0.5           4.0           1.5           0.6           0.4           100          100          50            40            10            0.5

Summer Squash

Deficient         <3.0               0.25          2.0           1.0           0.3           0.2           40            40            20            25            5              0.3

Adequate      3.0-5.0         0.25-0.5    2.0-3.0     1.0-2.0    0.3-0.5    0.2-0.5     40-100     40-100     20-50       25-40      5-20       0.3-0.5      
Range

High                 >5.0               0.5           3.0           2.0           0.5           0.5           100          100          50            40            20            0.5

 Watermelon

Deficient          <2.5               0.25         2.7           1.0           0.25         0.2           30            20            20            20            5              0.3

Adeqaute       2.5-3.5       0.25-0.50  2.7-3.5     1.0-2.0    0.25-0.50   0.2-0.4    30-100    20-100     20-40       20-40       5-10     0.3-0.5
Range

High                 >3.5               0.5           3.5           2.0           0.5           0.4           100          100          40            40            10            0.5

Petiole Sap Testing
Fresh sap can be pressed from leaf petiole and analyzed for nitrogen and potassium concentrations.  Results can be used to make adjustments in the fertilization program.  Below are the sufficiency range for sap testing for cucurbits. 

Crop Development Stage                                                                    Fresh Petiole Sap Concentration (ppm)

                                                                                                                              NO₃-N                     K

Cucumber
First blossom                                                                                                        800-1000                 NR¹
Fruit three-inches long                                                                                        600-800  
First Harvest                                                                                                         400-600

 Cantaloupe
First blossom                                                                                                        1000-1200               3000-3200
Fruits two-inches long                                                                                        800-1000                 -
First harvest                                                                                                          700-800                   - 

Squash
First blossom                                                                                                        900-1000                 NR¹
First harvest                                                                                                          800-900                    

Watermelon
Vines 6” in length                                                                                                1200-1500               4000-5000
Fruits 2” in length                                                                                                1000-1200               4000-5000
Fruits one-half mature                                                                                         800-1000                 3500-4000
At first harvest                                                                                                     600-800                   3000-3500

¹NR - No recommended ranges have been developed