TISSUE SAMPLING TECHNIQUES FOR SPECIFIC PLANTS
Illustrations of Best Sampling Areas
Crop When to Sample Where to Sample
Plants to Sample
FIELD CROPS
Alfalfa Early bloom set Upper 1/3 of plant
12-30
Canola Before seed set Recently mature leaf
60-70
Clover Before bloom Upper 1/3 of plant
30-40
Corn/sweetcorn Seedling stage
or
Before tasseling
or
Tasseling to silking

All above-ground portion

Recently mature leaf

Leaf opposite/below ear

15-20

12-20

12-20
Cotton Full bloom Recently mature leaf
40-50
Flax Seedling stage
or
Before heading

All above-ground portion

Recently mature leaf

50-60

50-60
Grasses/forage mixes Stage of best quality Upper 4 leaves
30-40
Peanuts Before/at bloom Recently mature leaf
40-50
Small Grains
(barley, oats, wheat,
rye, rice, etc.)

Seedling Stage

Before Heading

All above-ground portion

Upper 4 leaves

25-40

25-40
Sorghum (milo) Before/at heading 2nd leaf from top
20-30
Soybeans Before/at bloom Recently mature leaf
20-30
Sugarbeets Midseason Recently mature leaf at center of whorl
25-30
Sugarcane Up to 4 months old 4th fully developed leaf from top
15-20
Sunflowers Before heading Recently mature leaf
20-30
Tobacco Before bloom Recently mature leaf
10-15
ORNAMENTALS AND FLOWERS
Carnations Newly planted
Established		 4th-5th leaf pair from base
5th-6th leaf pair from base
20-30
20-30
Chrysanthemums Before/at bloom Top leaves on flowering stem
20-30
Ornamental trees and shrubs Current year's growth Recently mature leaf
30-70
Poinsettias Before/at bloom Recently mature leaf
15-20
Roses At bloom Recently mature compound leaf
on flowering stem
25-30
Turf Active growth Leaf blades. Avoid soil contamination
2 cups
VEGETABLE CROPS
Asparagus Maturity Fern from 18-30 inches up
10-30
Beans Seedling stage
or
Before/at bloom

All above-ground portion

Recently mature leaf

20-30

20-30
Broccoli Before heading Recently mature leaf
12-20
Brussels Sprouts Midseason Recently mature leaf
12-20
Celery Midseason Outer petiole of recently mature leaf
12-20
Cucumbers Before fruit set Recently mature leaf
12-20
Head Crops
(Cabbage, cauliflower, etc.)		 Before heading Recently mature leaf at center of whorl
12-20
Leaf Crops
(Lettuce, spinach, etc.)		 Midseason Recently mature leaf
12-20
Melons Before fruit set Recently mature leaf
12-20
Peas Before/at bloom Leaves from 3rd node from top
40-60
Peppers Midseason Recently mature leaf
25-50
Potatoes Before/at bloom 3rd-6th leaf from growing tip
25-30
Root/bulb crops
(Carrots, beets, onions, etc.)		 Midseason before root or bulb enlargement Recently mature leaf
20-30
Tomatoes (field) Mid-bloom 3rd-4th leaf from growing tip
15-20
Tomatoes (trellis or indeterminate) Mid-bloom from 1st to 6th
cluster stage		 Petiole of leaf below or
opposite top cluster
12-20
FRUIT AND NUT CROPS
Apples, pears, almonds, apricots, cherries, prunes, plums Midseason (June-July) Leaves from current season's non-fruiting,
non-expanding spurs
50-100
Figs, olives, peaches, nectarines Midseason (June-July) Basal to mid-shoot leaves from current
season's non-fruiting shoots
25-100
Blueberries 2-4- weeks before harvest Mid-shoot leaves from current season's shoots
50-100
Citrus Late season (September-October) Terminal Leaves from current season's
non-fruiting shoots
25-40
Grapes Mid-bloom Recently mature petioles or leaves
adjacent to basal clusters
50-100
Kiwi fruit Midseason 1st-3rd leaf beyond fruit or
mid-cane leaves if non-bearing
50-60
Pecans Midseason Paired mid-shoot leaflets from
non-fruiting shoots
25-60
Pistachios Late season (August) Terminal leaflets from non-fruiting shoots
25-60
Raspberries Midseason Recently mature leaves from laterals
of primo canes
30-50
Strawberries Midseason Recently mature leaves
25-40
Walnuts Midseason (June-July) Terminal leaflets from non-fruiting shoots
25-40