Alfalfa, Clovers, Trefoil and Legumes

6" to early bloom

Sample top 6" or top one-half or plant if plant is less than 8" tall from 35 plants

Small Grains & Grasses Seedling

Seedling

Sample entire above ground portion of 40 plants

Prior to head emergence

Sample top leaves down to 4th or 5th leaf from 50 plants

Grain Sorghum or Sorghum-Sudan

Prior to head emergence

Sample 2nd fully developed leaf from top of 20 plants  

Soybeans, Field Beans and Peas

Prior to or during initial flowering

Sample first fully developed trifoliate and petiole from the top of 25 plants

Beets, Radishes and Celery

Anytime during growing season

Sample petioles of recently fully expanded mature leaves from 20 plants

Potatoes

Prior to and during early flowering

Sample petiole and leaf blades of the 4th leaf from the growing tip of 40 plants

Corn

Seedling

Sample entire above ground portion of 20 plants

Prior to tasseling

Sample fully developed leaf below the whorl.  Sample 15 plants

Tasseling through silking

Sample ear leaf of leaf opposite and below ear.  Sample 15 plants

Fruit Trees

Mid-July through August

Include only one cultivar or strain in a sample and select most recently developed leaves from new growth