Plant Tissue Analysis

Plant analysis is an important tool that supplements soil testing to ensure plant health. A plant tissue analysis will show what nutrients the plant is taking up throughout the entire rooting zone and whether the levels found are adequate, deficient, or excessive. A soil test is limited to the depth of sampling, unlike a tissue analysis. Many people will look to a tissue analysis when troubleshooting by comparing a “good” with a “bad” area.

Plant Tissue Sampling Instructions

See below for some sampling guidelines

Each plant tissue sample needs to be 75-110g in weight or about 2 cups. See below for leaf blade totals based on leaf size. Consider sampling at different stages of growth throughout the year, or annually, to monitor trends. Collect from 20 to 40 locations within a selected area: enough to “average” out variations.

Large Leaf: 30 leaves
Mid-sized leaf: 50 leaves
Small Leaf: 100 leaves
Petiole: 50-75 petioles

Basic knowledge of plant structure is necessary before collecting samples. A leaf is made up of a leaf “blade” and a “petiole”. The petiole is the stalk attached to the blade. It is the preferred plant part sampled in grapes. Petioles are sampled in many vegetables and crops such as cotton and sugarbeet when determining nitrate-nitrogen levels through the growth of the crop. “Midribs” are the middle ribs to large leaves such as corn, lettuce, and cabbage, and would equate to a petiole sampling. A compound leaf may have several “leaflets” attached to it. In some cases, only terminal “leaflets” may be sampled, as in the case of walnuts. A common error in tomatoes is when only leaflets are sampled instead of the whole compound leaf. This shows the importance of understanding the proper sampling technique. In general terms, “most recently matured” plant tissue should be selected.

Sample Information

Identify each sample with numbers and/or letters, by row number or field for example, or good versus bad. Avoid numbering samples simply as 1,2,3 … as it may lead to confusion later. Indicate the analysis desired and provide very specific information on the stage of growth and plant part if an interpretation is required. Select either the standard format (three samples per page) or the graphical format (one sample per page). Refer to the product list for different analytical packages. The laboratory does not automatically provide an interpretation, as some clients prefer to make their own.

Shipping Samples

If samples are very wet, air-dry them to a workable condition before packaging. Otherwise, decomposition or molding will occur. Include a completed plant analysis information sheet or cover letter with instructions within the same package. Processing will be delayed if sent separately. Also, include payment if you do not have an established account.

Samples should be shipped by a carrier such as UPS or FEDEX, or by first class mail.