Important Tips

  • Samples submitted for nematode assay cannot be tested for lime requirements or plant nutrients. For this information, you must submit a separate soil sample in a soil sample box. Please visit the Soil Testing site to determine how to submit these samples.
  • Take samples only when soil is in good working condition. It should not be frozen, nor should it be excessively wet or dry.
  • Boxed samples must be protected from overheating and freezing. Do not place samples in direct sunlight, the trunk of a car or a freezer.
  • Ship samples as soon as possible after collection.

What to use:

Use sample boxes, bags and information forms designed specifically for nematode assays. They are available from the NCDA&CS Agronomic Services Division office in Raleigh, your local Cooperative Extension office and many ag-chemical dealers.

  • Nematode specific boxes and bags provided by NCDA&CS. 
  • Soil probe or shovel.
  • Bucket.

How to collect

Field crops. Take a sample from each section of a field with a distinct crop history. For example, if a 4-acre field will be planted in tobacco next year and if half of it is currently planted with corn and half with soybeans, then you need to take two separate samples: one from the corn field and one from the soybean field. To obtain representative samples from larger fields with uniform crop histories, divide fields into 4- to 5-acre units and then select samples from at least half of these units. Label samples carefully for your records.

Home gardens. One sample is sufficient, except for areas larger than one-half acre or where soil type differs greatly from one end of the garden to the other.

Ornamentals, shrubs, trees & turfgrass. Send a separate sample for each plant species and specify the plant name. For example, American boxwood is a good description; shrub is not.

nematode sampling patterns for a 4 acre field

How much to collect

soil collected for nematode assay and placed in box and plastic bag
  • Collect at least 20 soil cores to a depth of 4 to 8 inches. Thoroughly mix the cores together in a plastic bucket.
  • Use this mixture to fill the plastic bag that comes with the nematode assay sample box. Seal the bag tightly, and place it inside the sample box. Sample box should be completely full.
  • Print your name, address and sample ID in the spaces provided on the box. If you are using a Farm ID to identify a group of samples, then you will also need to write the Farm ID on each box.
  • If soils vary in the sampled area, take a separate sample for each soil type.

This page was last modified on 01/09/2024