Leaf Sampling Procedure
Sampling Procedures for Plant Analysis
Plant analysis is the second tool, after soil testing, that is critical to improving crop nutrition and yield. Only plant analysis can identify the actual nutrient status of a plant or crop. While soil testing identifies the nutrients offered to the crop or plants, plant analysis identifies how well the plants utilized the soil and applied nutrients. Plant analysis allows the crop or plant to tell us what nutrients it needs.
It is critical that the correct plant part and stage of growth be sampled, and that the label clearly informed of this.
The normal nutrient concentration differs between the various plant parts. Also, the normal nutrient concentration of each plant part changes as the plant matures. Plant analysis is calibrated to these norms, so correct identification of which nutrients are low or high depends on accurate information. Call our Laboratory if you have a plant not listed.
How to Take Plant Samples
1. Where to Take Samples
A. In Uniform Fields
Where plant grow this uniform over the entire area, one composite sample, taken from at least 10 widely scattered areas in the field. One plant sample is necessary. One soil sample is recommended.
B. In Problem fields
These are where the growth or appearance of one area differs from the rest of the field. Plant analysis can often determine the cause of these differences and indicate the best method to correct the problem. Sample when abnormalities are discovered. Two plant and two soil samples are required. This includes collecting soil and plant samples from the normal area.
All plant samples taken from abnormal areas should be taken from just inside of the abnormal area. Soil samples should be taken through out the abnormal area.
A separate Plant Analysis History must be completed for each sample taken.
2. When to Take Samples
Crops can be sampled during most of the season. The following tables list the preferred plant parts and growth stages to sample for many crops.
3. Amount of Plant Material
All plant analysis requires at least a rounded double handful(soft ball size) of plant tissue. We find it difficult to analyze a sample that is too small. See the tables on the following pages for the proper number of plant parts to sample.
4. Preparing Samples for Shipping
Use a large, clean paper bag or clean plastic bucket to collect the sample. Remove any dust or residue from the leaf surface with a clean dry soft bristle brush. Do not wash the sample. Improper washing can affect the nutrient content of some elements.
5. Sample Submission Form
Perhaps the most important part of a plant sample is its accompanying Plant Submission Form. This form can be downloaded from submission form. Be sure to indicate if more than one sample is being sent at the same time.
6. Sending the Sample
Place the collected leaf samples in perforated Cropnuts sample bags, ensuring adequate air circulation to prevent moisture build-up during transit.
Do not send fresh samples or put them into plastic bags. They will decompose during shipment, making them useless for analysis purposes.
IMPORTANT: Accurate Analysis and meaningful interpretation require properly taken samples.
Follow these and all directions carefully and correctly.
|CROP||GROWTH STAGE||PLANT PART TO SAMPLE||QUANTITY|
|AGRONOMIC AND FORAGE CROPS|
|Alfalfa||At or prior to 5% bloom||Entire above ground portion of plant or top 6”,which ever is smaller.||15 to 20 plants|
|Barley,Oats, Rye,Wheat (othersmall grainsexcept rice)||
a) Feekes Stages 3 through 9
b) Feekes Stage 10
Entire above ground portion of plant.
Upper most mature, or Flag leaves.
30 to 40 plants, depending on size
30 to 40 leaves
|Canola||Seedling to Vegetative At or prior to full bloom||Whole plant Fully developed leaves on upper portion of plant||20 to 30 leaves 20 to 30 leaves|
|Corn(Field,Pop,and Silage)||(a)Seedling(6”to 12”)tall(<V 6) (b) Prior to tasseling, (V 7-VT) (c)Silk initiation to brown silk stage (R 1-R 5)||Entire above ground portion of plant. First fully developed leaf below whorl. Ear Leaves.||15 to 20 plants 10 to 15 leaves 10 to 15 leaves|
|Cotton||(a)Seedling,6”to 12”tall(b) Prior to or at first bloom(c) When first squares appear||Entire above ground portion of plant Youngest fully mature leaves from the main stem of plant. Discard the petioles.||15 to 20 plants 15 to 20 leaves|
|Cotton (Petioles)||When first squares appear to full maturity||Petioles from the youngest fully mature leaves on the main stem of plant.||30 to 50 petioles|
|Grasses(Hay,Forage or Pasture)||Prior to heading||Entire above ground portion of plant or top 6”,which ever is smaller.||25 to 30 plants|
|Peanuts||(a)Seedling stage (b) Vegetative to pegging stage||Entire above ground portion of plant. Youngest fully mature leaf. No petioles.||15 to 20 plants 20 to 30 leaves|
(a)Seedling stage (b) Tillering
(c)1st Joint-Panicle Initiation
(d) Panicle differentiation
Entire above ground portion of plant. Entire above ground portion of plant. Y Leaf/ Flag Leaf Y Leaf /Flag Leaf
Y Leaf/ Flag Leaf
15 to 20 plants 15 to 20 plants
20 to 30 leaves
15 to 20 leaves
20 to 30leaves
|Soybeans||(a)Seedling stage(V 2-V 5) (b) Vegetative to early pod fill(>V 5)||Entire above ground portion of plant. Youngest fully mature leaf. No petioles.||15 to 20 plants 20 to 30 leaves|
|Sugar Cane||2 Months to Mature||Second fully mature leaf without sheath.||15 to 25 leaves|
|Sunflowers||(a)Seedling stage (b) Vegetative to full bloom||Entire above ground portion of plant. Youngest fully mature leaf. Nopetioles.||15 to 20 plants 15 to 20 leaves|
|Tea||During period of active growth||First mature leaf||30-50 leaves|
|Tobacco||(a)Seedling (transplants,2 wks.+) (b) Vegetative stages||Entire above ground portion of plant. Youngest fully developed leaf from top.||15 to 20 plants 10 to 20 leaves|
|Asparagus||(a) Spears (b) Ferns||Entire above ground portion of plant. Youngest mature frond(top 24 inches).||10 to 20 spears 10 to 20 fronds|
|Beans (Field/Dry, Snap, Lima,etc.)||(a) Seedling stage (b) Vegetative to early pod fill||Entire above ground portion of plant. Youngest fully mature leaf. No petioles.||20 to 30 plants 20 to 30 leaves|
|Beets,Table||Vegetative stages.||Innermost mature leaf in the whorl.||25 to 50 leaves|
|Broccoli,Cabbage, Cauliflower||(a) Seedling stages (b) Vegetative to heading stages||Entire above ground portion of plant. Mature fully expanded wrapper leaf.||20 to 30 plants 15 to 20 leaves|
|Carrots||(a) Seedling stages (b) Vegetative stages.||Entire above ground portion of plant Innermost mature leaf in the whorl.||20 to 25 plants 25 to 50 leaves|
|Celery||Vegetative stages||Petiole of youngest mature leaf.||20 to 25 petioles|
|Collard,Kale, Mustard, Turnip||Vegetative stages||Youngest mature leaf.||15 to 20 leaves|
|Eggplant||Vegetative to full bloom stage.||Youngest mature leaf on main stem.||25 to 35 leaves|
|Lettuce, Spinach, Endive||Vegetative stages||Youngest mature leaf.||20 to 30 leaves|
|Melons (cantalope/ muskmelon, watermelon)||Vegetative to fruiting||Youngest fully mature leaf. No petioles.||15 to 20 leaves|
|Onion,Garlic, Leek,Shallot||(a) Seedling stages (b) Vegetative stages||Entire above ground portion of plant. Entire above ground portion of plant.||30 to 50 plants 25 to 30 plants|
|Peas (Field/sweet etc.)||(a) Seedling stage(4-17 nodes) (b) Vegetative to early bloom||Entire above ground portion of plant. Youngest mature leaf. No petioles.||20 to 30 plants 25 to 35 leaves|
|Peppers (Chili,Sweet)||Early Vegetative to Fruiting Stage.||Youngest mature leaf on main stem.||25 to 35 leaves|
|Potato,sweet||(a) Seedling stages (b) Vegetative to full bloom stage.||Entire above ground portion of plant. Youngest mature leaf on main stem.||20 to 25 plants 25 to 30 leaves|
|Potato,white||(a) Seedling stages (b) Vegetative to full bloom stage.||Entire above ground portion of plant. Youngest mature leaf on main stem.||20 to 25 plants 25 to 30 leaves|
|Radish||(a) Seedling stages (b) Vegetative stages.||Entire above ground portion of plant. Innermost mature leaf in the whorl.||20 to 25 plants 40 to 50 leaves|
|SweetCorn||(a) Seedling(6”to 12”)tall(<V 6) (b) Prior to tasseling(V 7-VT) (c) Silk initiation to brown silk stage (R 1-R 5)||Entire above ground portion of plant. Youngest mature leaf below whorl. Ear Leaf.||15 to 20 plants 10 to 15 leaves 10 to 15 leaves|
|Squash, Pumpkins||Vegetative,bloom,fruiting||Youngest mature leaf. No petioles.||15 to 20 leaves|
|Tomato (Field-See Pic)||(a) Seedling stages (b) Vegetative,bloom,fruiting||Entire above ground portion of plant. Youngest mature leaf on main stem.||20 to 25 plants 20 to 30 leaves|
|Tomato (Greenhouse) See Pictorial||(a) Early Flowering (b) 1st to 6th Cluster||Leaf Tip Terminal leaf or leaflet next to most recent fruiting cluster (identify cluster)||20 to 25 plants 50 to 70 leaves|
|Almond||Mid-season(6-8 weeks after bloom)||Terminal leaflets from mature leaves on terminal shoots.||25 to 40 leaflets|
|Apples||Mid-season(4-8 weeks after bloom)||Youngest fully mature leaves from mid- terminal(non-bearing spur,if spur type).||20 to 30 leaves|
|Apricots||Mid-season(4-8 weeks after bloom)||Youngest fully mature leaves of current years growth.||20 to 30 leaves|
|Blackberry Raspberry (other brambles)||Mid-Season(2-6 weeks after bloom)||Mature leaves from mid-section on non- fruiting“primo”canes.||20 to 30 leaves|
|Blueberry||Mid-season(4-6 weeks after bloom) Post-harvest(July 15-August 15)||Median leaves,non-fruiting branches. Youngest fully mature leaves.||40 to 60 leaves 40 to 60 leaves|
|Cherry (sweet,tart)||Mid-season(4-8 weeks after bloom)||Youngest fully mature leaves from mid- terminal on a non-bearing spur.||20 to 30 leaves|
|Citrus||(a)Vegetative stages (b) Fruiting stages||Fully mature leaf-spring cycle growth. Fully mature leaves adjacent to fruit.||20 to 30 leaves 20 to 30 leaves|
|Cranberry||Late August early September, ONLY||Upper 2 inches of“uprights”from the current season’s growth. Include stem.||50 to 100 uprights|
|GrapeLeaves||(a)Vegetative stages (b) Fruiting stages||Youngest fully mature leaf.(Remove Petioles) Leaf opposite basal fruit cluster.||15 to 25 leaves 15 to 25 leaves|
|GrapePetioles||(a)Vegetative stages (b) Fruiting stages||Youngest fully mature leaf Leaf opposite basal fruit cluster.||50 to 75 petioles 50 to 75 petioles|
|Macadamia||During major flush||First young full developed, hardened off leaf behind new flush||40-60 leaves|
|Peaches||Mid-season(4-8 weeks after bloom)||Youngest fully mature leaves near base of current years growth.||20 to 30 leaves|
|Plums||Mid-season(4-8 weeks after bloom)||Youngest fully mature leaves near base of current years growth.||20 to 30 leaves|
|Strawberry||Vegetative to fruiting stages||Youngest fully mature tri-foliate leaf.||50 to 60 leaves|
|Walnut, English||Mid-season(6-8 weeks after bloom)||Terminal leaflets from mature leaves on terminal shoots.||25 to 40 leaflets|
|ORNAMENTALS, TREES and TURF|
|Ferns||Vegetative growth||Youngest fully expanded mature frond||15 to 30 fronds|
|FloweringAnnuals||Vegetative to full bloom||Uppermost mature leaves on main stem.||20 to 40 leaves|
|HerbaceousPerennials||New season vegetative growth||Youngest fully developed leaves of the current year’s growth.||20 to 40 leaves|
|Roses||All stages||Upper three leaflets from youngest fully mature leaves.||30 to 40 leaflets|
|Trees,Shrubs (Conifers)||Vegetative growth,mid season||Current season’s“lateral”,fully hardened.||15 to 20“laterals”|
|Trees,Shrubs (Deciduous)||Vegetative growth stages||Youngest fully developed leaves of the current year’s growth.||20 to 50 leaves|
|Turf||Vegetative growth||Leaves,preferably clipped by hand.||1 pint clippings|
Sample uppermost mature leaf.
Sample uppermost mature leaf or main stem Sample terminal leaflet or leaf next to most recent fruiting cluster
(Leaves or Petioles)
Vegetative: Sample youngest fully mature leaf.
Fruiting: Sample leaf opposite basal fruit cluster.
Leaf: for complete nutrient analysis
Petioles: for nitrate monitoring only
Effective Uses for Plant Analysis
1. Confirm visual deficiency symptoms.
2. Reveal hidden nutrient stresses.
3. Check up on the effectiveness of a fertility program.
4. Improve yield goals and fertilizer needs for future crops.
5. Improve quality of plants
A Complete Plant Analysis from Crop Nutrition Laboratory Ltd includes the total amounts found of the
nutritional elements, N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, Na and Zn.
The status (Deficient, Low, Normal, High, Very HIgh.) for each nutrient tested is indicated numerically on
the report and a colored bar graph. A complete agronomic interpretation of the analytic results is also
Some Plant Analysis Do’s and Don’ts
1. Collect a representative sample. Sample the field as you would if you were sampling the soil (10-20
2. Always collect sufficient plant material (see “Quantity” tables).
3. Fill out the plant history questionnaire as completely and accurately as possible. The more complete the
information the more reliable the interpretation.
4. Always identify the age and growth stage (seedling, bloom, Feekes, V/R, etc.) as accurately as possible.
5. Indicate if foliar fertilizers or fungicides have been recently applied. Identify them and record their
application rates in the questionnaire. Again, it will make for a more reliable interpretation.
6. Always collect a soil sample from problem areas.
7. When in doubt, Read the Instructions or call or email the lab.
8. Make PLANT ANALYSIS a central part of your agronomic services program.
1. Sample dead plants.
2. Wash leaf tissue
3. Collect or ship samples in plastic bags or containers.
4. Use galvanized equipment in any way.
5. Sample severely insect damaged plants.
6. Sample severely mechanically injured plants.
7. Sample plants that are too old (see “Growth Stage” tables).
8. Sample during severe drought.
9. Samples covered with dirt/soil particles.
For more information please contact us through:
Crop Nutrition Laboratory Services Ltd.
Telephone +254 (0) 736 839 933, + 254 (0) 720 839 933