Use the table below as a guide for taking samples:
- A leaf or blade sample should consist of 15 or more sub-samples taken at random throughout the area being sampled. A petiole sample should consist of 25 or more sub-samples taken at random. For potatoes, submit a minimum of 40 petioles per sample.
- If a sample is taken from a problem area, obtain a comparison sample from a good area. Soil samples from the problem and good areas are helpful to identify the problem.
- Avoid sampling along dusty roads.
- Note samples that have received foliar fertilizer applications so the samples can be rinsed before analysis.
- Place sample in paper bag and ship to the laboratory with a leaf or petiole sample submittal form. Do not mail samples in plastic bags or other air-tight containers.
Crop Stage of Growth Plant Part
|
FIELD CROPS Alfalfa, clover |
1/10 bloom stage |
Mature leaf blades from upper 1/3 of plant |
|
Beans (soybeans, field beans) |
Seedling (up to 12” tall) |
All above ground portion of plant |
|
|
Prior to or at flowering |
Most recent fully matured trifoliate leaves |
|
Corn |
Seedling (up to 12” tall) |
All above ground portion of plant |
|
|
Prior to tasseling |
Most fully developed leaf below whorl |
|
|
Tassel or early silk |
Ear leaf |
|
Cotton |
Prior to appearance of first squares |
Petiole from fully expanded leaf on main stem, usually 3rd or 4th leaf from terminal |
|
Grass
|
At optimum stage for quality forage or prior to heading
|
Four uppermost leaves
|
|
Small grain – wheat, barley, oats, rye, triticale |
Seedling prior to jointing Prior to heading |
All above ground portion of plant Four uppermost mature leaves |
|
Sorghum/milo |
Seedling (up to 12” tall) |
Whole plant |
|
|
Prior to heading Soft Dough
|
Fully Expanded Leaf Third Leaf Below Head
|
|
Sugar beets |
Mid-season |
Most recent mature leaf without petiole |
|
|
During growing season |
Petiole from most recent mature leaf |
|
FRUIT AND NUT CROPS Apple, cherry, peach, pear
|
Mid-season
|
Leaves near base of current year’s growth or from spurs
|
|
Grapes
|
End of bloom period
|
Petioles from leaves adjacent to fruit clusters
|
|
Lemon, lime
|
Mid-season
|
Mature leaves from last flush or growth on non-fruiting terminals
|
|
Orange
|
Mid-season
|
Spring cycle leaves, 4 to 7 months old from non-bearing terminals
|
|
Pecan
|
6 to 8 weeks after bloom
|
Middle pair of leaflets from mid-portion of terminal growth
|
|
Pistachio
|
6 to 8 weeks after bloom
|
Leaflet from mid-portion of non-bearing branches
|
|
VEGETABLE CROPS Cantaloupe |
During growing season |
Petiole of 6th leaf from growing tip |
|
Cucumber
|
Early fruit set
|
Petiole of 6th leaf from tip
|
|
Muskmelon
|
During growing season
|
Petiole of 6th leaf from growing tip
|
|
Onion |
During growing season |
Tallest leaf |
|
Pepper – chili |
During growing season |
Petiole of young, mature leaf |
|
|
During growing season |
Blade of young, mature leaf |
|
Pepper – sweet |
During growing season |
Petiole of young, mature leaf |
|
|
During growing season |
Blade of young, mature leaf |
|
Potato
|
During growing season
|
Petiole of 4th leaf from growing tip
|
|
Pumpkin
|
Early fruit set
|
Petiole of 6th leaf from growing tip
|
|
Spinach
|
Midgrowth
|
Petiole of young, mature leaf
|
|
Tomato |
During growing season |
Petiole of 4th leaf from growing tip |
|
|
During growing season
|
Blade of 4th leaf from growing tip
|
|
Watermelon
|
Early fruit set
|
Petiole of 6th leaf from growing tip
|
|
ORNAMENTALS Ornamental trees, shrubs
|
Current year’s growth
|
Fully developed leaves
|
|
Turf |
During normal growing |
Leaf blades |