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Sample Testing Instructions

Soil Sampling


  1. Use clean tools and buckets for each depth of sample taken ex: 1’, 2’& 3’.
  2. Make sure to clean tools and bucket between fields.
  3. Thoroughly mix the soil in the bucket and break up any clods.
  4. Place approximately 2 cups of soil in properly labeled soil bags (field name, and depth) or pint sized freezer Ziploc bags.
  5. At the end of each day bring in or ship your samples to the lab.
  • 1’(12 inch) samples are most common, any deeper than 1’ is usually divided into two samples (1’ and 2’). Greater depths are necessary for deep rooting crops.
  • If you are planning on taking one sample for a field, we would recommend a composite sample. This is an even representation of the whole field, a balanced number of probes from across the whole area. We will be happy to explain this in better detail if needed.
  • For lawns and garden areas take at least 5 cores.
  • Keep bags cool and out of the sun until they reach our facility.

Plant and Tissue Sampling


It is essential that the correct petiole be sampled as nutrient levels are not constant throughout most plants.

Potatoes: Starting at the top of the plant you count down 4 whorls. Once on the 4th whorl remove the entire leaf from the plant. Hold the leaf by its stem end and strip off the leaflets. Save the bare petiole for analysis.Approximately 25-30 petioles are needed for testing. If the petioles are large we will not need as many and if the petioles are small we will need more.

Wheat: Collect the four uppermost leaf blades from the tops of 30-35 plants. (on seedlings collect all of the above ground portion.)

Tree Leaves: Roughly 50 leaves from the base of the current year’s growth. (can be from multiple trees throughout an orchard.)

Feed and Forage Testing


  • Use a Forage probe to take the sample.
  • Each unit should be probed 20 times in a random manner around the unit.
  • Bales should be probed horizontally centered in the end of the bale.
  • Combine all cores and mix thoroughly in a plastic bag.
  • Place sample in a properly labeled bag and bring into lab.

Compost and Organic Compost Testing


  1. Sampling Solids- Take at least 20 sub samples from all different depths from the stack or pile and composite. Place in an AV Labs soil bag or a quart Ziploc freezer bag.
  • If you need Pathogens, Heavy Metals, and Nutrients we will need 2 separate gallon Ziploc freezer bags.
  1. Sampling Lagoons- Agitate if possible to 2-4 hours, if agitation is not possible take at least 20 sub samples from all depths of the lagoon to make your composite sample.

Drinking Water Analysis for Bacteria & Nitrate


  1. The best location is NOT the kitchen sink. (bathtub)
  2. Clean the sample area with rubbing alcohol and wash your hands thoroughly.-let water run until rubbing alcohol is gone
  1. Remove the lid, careful not to touch the inside of the lid or bottle.
  2. Fill the bottle to the fill line.
  3. Make sure that your Chain of Custody paper is filled out properly.
  4. Keep cold until it reaches the lab. Bacteria samples must be received within 24 hours of sampling. After 30 hours the sample is no longer valid.
  5. Bottles may be picked up at the AV Labs Inc.
  6. Water samples are accepted Monday thru Thursday by 3:30 p.m.
  7. For IOC, SOC and other samples the source is where the sample needs to be taken from.
  8. Holding times differ for different analysis please call for more information.
  Bacteria and Nitrate sample bottles can be picked up at AV Labs Inc or Grant County Health Department in Moses Lake, Wa.
 AV Labs Inc, will courier water samples from the Grant County Health Department on Tuesdays and Thursdays at 1:00 p.m.  All samples need to be at the Grant County Health Department by 1:00 p.m. for pick up.

Gap Sampling


Remove the lid making sure not to touch the inside of the lid or bottle.

  • Fill the bottle to the fill line.
  • Keep cool until delivery to AV Labs Inc.
  • Fill out the Gap Microbiological Analysis form. *Forms can be downloaded.
  • Make sure to properly label all bottles.
  • Bottles must be into AV Labs Inc. within 24 hours.
  • Gap samples are accepted Monday thru Thursday by 3:30 p.m.