AGRONOMIC CROPS Stage of Growth Plant Part to Sample Number of Plants or Leaves to sample
Alfalfa Prior to or at 1/10 bloom stage Mature leaf blades taken from the top 4 to 6 inches of the plant 40-50
Clover and Other Legumes Prior to bloom Mature leaf blades taken about 1/3 of the way down from top of the plant. 40-50
Corn 1) Seeding stage (less than 12") All the above ground portion 15-20
2) Prior to tasselling The first fully developed leaf below the whorl 15-20
3) From tasselling and shooting to silking The entire leaf at the ear node (or immediatley above or below it). 15-20
Sampling after silking occurs is not recommended
Cotton Prior to or at first bloom or when first squares appear. Youngest fully mature leaves on main stem 30-40
Hay, Pasture or Forage Grasses Prior to seed head emergence or at the optimum stage for best quality forage Top 6 inches of plant 40-50
Peanut Prior to or at bloom stage. Mature leaves from both the main stem and either cotyledon lateral branch 40-50
Sorghum-milo Prior to or at heading Second leaf from top of plant 15-25
Soybean or other beans 1) Seedlings stage (less than 12") All the above ground portion 20-30
2) Prior to or during initial flowering Two or three fully developed leaves at the top of the plant 20-30
Sampling after pods begin to set not recommended.
Tobacco Before bloom Uppermost fully developed leaf. 8-12
Turf During normal growing season; at least two days regrowth Leaf blades. Clip by hand to avoid contamination with soil or other material. 1/2 pint of material
Wheat 1) Tillering (GS-3) to just prior to heading (GS 10-boot stage) All above ground portion 30-40
2) Just prior to heading (GS 10) Flag leaf 40-50
Sampling after heading not recommended.
FRUITS AND NUTS Stage of Growth Plant Part to Sample Number of Plants or Leaves to sample
Apple 8 to 10 weeks after full bloom Healthy mid-terminal leaves of current season's growth, taking 4 to 8 leaves per tree. 50-100
Apricot, Almond, Cherry, Pear, Prune Mid Season Healthy mid-terminal leaves of current year's growth or spurs. 50-100
Blueberry, Rabbiteye First two weeks after harvest Mature leaves from mid-portion of current season's growth 25-40
Grape End of bloom period Petioles from leaves adjacent to fruit clusters. 60-100
Grape, Muscadine Mid to late summer but prior to final swelling of fruit Most recent mature leaves adjacent to fruit clusters. 25-30
Peach 12 to 14 weeks after bloom Mature leaves from mid-portion of near base of current season's terminal growth, taking 4 to 8 leaves per tree. 50-100
Pecan 56 to 84 days after catkin fall; July 7 to August 7 Middle pair of leaflets from midportion of terminal growth 100
Raspberry Mid season Youngest mature leaves on laterals or "primo" canes 20-40
Strawberry 4 to 5 weeks after peak bloom Youngest fully expanded mature leaves. 50-75
Walnut 6 to 8 weeks after bloom Middle pairs of leaflets from mature shoots. 30-35
ORNAMENTALS AND FLOWERS Stage of Growth Plant Part to Sample Number of Plants or Leaves to sample
Carnations 1) Unpinched plants 4th or 5th leaf pairs from base of plant. 20-30
2) Pinched plants 5th or 6th leaf pairs from top of primary laterals. 20-30
Chrysanthemum Prior to or at flowering Upper leaves on flowering stem 20-30
Ornamental Trees Current year's growth Fully developed leaves 30-100
Ornamental Shrubs Current year's growth Fully developed leaves. 30-100
Poinsettia Prior to or at flowering Most recently mature fully expanded leaves. 15-20
Rose During flower production Upper leaves on the flowering stem. 20-30
VEGETABLE CROPS Stage of Growth Plant Part to Sample Number of Plants or Leaves to sample
Asparagus Midgrowth Mature fern from 18-36" up 10-20
Beans 1) Seedling stage (less than 12") All the above ground portion 20-30
2) Prior to or during initial flowering Two or three fully developed leaves at the top of the plant 20-30
Head Crops (Cabbage, etc.) 1) Prior to heading First mature leaves from center of whorl 10-20
2) Head 1/2 grown Young wrapper leaf; 2 leaves per plant 10-20
Leaf Crops (Lettuce, Spinach, Turnip Greens, Collards, etc.) Mid growth Youngest mature leaf 35-55
Melons (Water, Cucumber, Muskmelon) Early stages of growth prior to fruit set Mature leaves near the growing tip of the plant 20-30
Peas Prior to or during initial flowering. Leaves from the third node down from the top of the plant 30-60
Peppers Prior to or at bloom stage. Most recently meature leaves 20-30
Potato, Irish Early flowering to tubers 1/2 grown Upper most mature 20-30
Potato, Sweet Midgrowth Most recently mature leaves 20-30
Root Crops (Carrots, Onion, Beets, etc.) Prior to root or bulb enlargement Center mature leaves 20-30
Sweet Corn 1) Prior to tasselling The entire fully mature leaf below the whorl. 20-30
2) At tasselling The entire leaf at the ear node 20-30
Tomato (Field) Prior to or during early bloom stage Third or fourth leaf from growing tip 20-25
Tomato (Greenhouse) Prior to or during fruit set 1) Young plants; leaves adjacent to 2nd or 3rd clusters. 20-25
Prior to or during fruit set 2) Older plants: leaves from 4th to 6th clusters. 20-25