Despite the Midwest’s wet spring and summer this year, most crops are now in the ground and plants have matured enough to produce foliage. Soil analysis laboratories are receiving whole plants, leaves, and clippings for plant tissue analysis – an examination and resulting recommendation of foliar and soil application to improve crop quality. However, without correct sample collection, plant tissue analysis accuracy can be greatly reduced.

“Plant nutrient makeup varies throughout the growing season. The recommendation systems that our laboratory utilizes to evaluate each sample have been developed based on specific plant parts at specific stages of growth. It’s important that the crops are sampled the same way that the research was developed so that the user can gain the most from the test,” explains Dustin Sawyer, laboratory manager for Rock River Laboratory. 

Following crop type and stage of growth guidelines, growers and consultants can easily select the correct plant portion, and collect the necessary number of plants, for the laboratory to provide reliable data to recommend the most accurate corrective measures. For easy instruction, growers and consultants can find guideline tables at:

In the case of an assumed nutrient deficiency, sample collection should include the same portion of the plants, in the same growth stage, from both the affected area and the normal area. “This analysis of suspected plants versus the control allows for a comparison of nutritional statuses for the best assessment,” explains Sawyer.  He also notes time is of the essence for samples of suspected nutrient deficiencies. “The sooner we can receive the plant tissue samples for an assumed nutrient deficiency, the better the opportunity that we can identify the deficiency and start the corrective action to minimize losses,” says Sawyer.

Beyond sample collection, handling, preparation and shipping of plant tissues have also proved to be areas of vulnerability to obtaining accurate analysis. After sampling, those handling the samples should follow preparation guidelines[1]:

  • Remove sample roots or foreign material
  • Dust off plant tissue – removing any remaining soil
  • Do not wash the sample
  • Air-dry the sample for 1-2 days utilizing a heating vent or the sun (only necessary if sample will reach the laboratory more than one day after sampling)
  • Loosely pack the sample in a paper envelop or paper bag when shipping (avoid tight packing)
  • Avoid utilizing plastic or polyethylene bags for sample shipment

While analysis of plant tissues can identify and help correct current crop deficiencies and challenges, the reactive recommendations can be improved with the proactive means of combining plant tissue and soil analysis. “Complex environmental interactions can lead to nutrient deficiencies in the plant, even when the soil may have an adequate supply for supporting the crops grown,” says Sawyer. “Sampling from plant tissue and soil at the same time gives us a comprehensive look at the nutrients and relationship between plant and soil, which allows us to make a more accurate and sustainable recommendation for applications.”

To learn more about soil and plant tissue analysis, growers and consultants can visit Rock River Laboratory’s resource room at:

Rock River Laboratory provides production assistance to the agricultural industry through the use of advanced analytical systems, progressive techniques, and research-supported analyses. Employing a team of top specialists in their respective fields, Rock River Laboratory is built on providing accurate, cost-effective, and timely analytical results to customers, while featuring unsurpassed customer service.