Sampling Instructions
Plant Sampling Instructions
In order for diagnosis of your sample to be effective and accurate, please carefully follow the below shipping requirements.
- Always select fresh plant material that is symptomatic but not dried out, dead, or decaying. We are unable to diagnose plants that are already dead.
- Do not ship live insects or arthropods. Crushed insects and insects stuck to clear tape are unidentifiable. Place insects in freezer to kill them. Preserve soft-bodied insects in a leak-proof vial of alcohol.
- Separate soil from plant material. If the root system is included, place a plastic bag around it and secure with a twist tie or rubber band to keep soil from contaminating leaves/stems.Place the entire sample into a sealed plastic bag. A dry paper towel can be wrapped around the plant to absorb excess moisture and prevent the plant from sticking to the plastic.
- Never add water to the sample for shipment–water will degrade the sample and prevent an accurate diagnosis.
- Ship in a crush-proof container such as a box. A box helps protect the sample and helps us provide an accurate diagnosis. Ship to the Plant Diagnostic Lab.
- Email us the tracking information so we know when to expect your package!
Soil Sampling Instructions
Follow the instructions below to obtain a representative sample. Limestone and fertilizer recommendations based on improperly collected soil samples may be inaccurate and possibly harmful to plants.
Tools:
- A stainless steel soil-sampling probe, an auger, or a shovel/trowel
- Clean bucket
- Plastic bags or waterproof lined paper bags
- Permanent marker
When and How to Sample:
Samples may be collected any time of year the ground is not frozen. The waiting period for results is longest in April and May. Testing the soil in the fall is highly recommended.
Submit a separate sample for areas differing in topography, drainage, soil texture, with different crop growth or intended crop usage, soil color, or fertilizer/amendment history. For example, a homeowner may submit one sample from a vegetable garden, one from a flower bed, and one from a front lawn. A farmer may submit a sample from each field, different crops, or from an area of low and/or high productivity. Under no circumstances should samples represent areas larger than 15 acres. Avoid sampling unusual spots such as former sites of manure or compost piles and areas where limestone or fertilizer has been spilled in previous years. The soil sample should accurately represent the entire sampling area.
Sample Collection
- Using an auger, spade, trowel, or bulb planter, collect cores or thin slices of soil from 12 or more random, evenly distributed spots (sampling points) in your sample area (see the diagram above) to the appropriate depth indicated below.
- Grass – 3 to 4 inches,
- Flowers, vegetables, small fruits – 6 to 8 inches
- Trees and shrubs – 8 to 10 inches
- Crop field: 6 to 8 inches or the plough layer depth
- When using a soil probe, insert it into the soil to the proper depth (e.g., 0-6” or 0-8” for flowers, vegetables, and fruits). If a tool such as a spade is used, dig a V-shaped hole to the sampling depth; then cut a thin (approximately 1 inch thick) slice of soil from one side of the hole. For the sample, save a 1-inchwide strip of soil from the center of the spade.
- Remove the soil core or the slices and place them into a clean bucket. Repeat this process at each predetermined subsampling point within your designated area. Thoroughly mix the soil to obtain one representative sample from that sampling area. Transfer at least 1 cup of this mixed soil to a plastic zippered bag. 2 cups if requesting extra tests.
- Using a permanent marker, label each plastic bag with a sample ID (e.g., “front lawn,” “garden1”) that matches exactly the sample ID in your sample submission form.
- Samples can be submitted in person or mailed. When mailing samples, place the sample bags and the submittal form in a sturdy box or envelope. Seal the box with packing tape and mail it to the Soil Nutrient Analysis Lab.
Compost Sampling Instructions
For compost testing, the goal is to send Soil Nutrient Analysis Lab (SNAL) a sample that truly represents the whole pile. Compost can vary a lot within the same windrow or pile, so a single grab sample from one spot is rarely enough.
Collect a representative composite sample
Plan to build one composite sample from multiple subsamples taken from different areas and depths.
- Sampling locations: In most cases, collect material from at least 5 different spots around the pile or along the windrow (more if the pile is large).
- Sampling depths: At each location, take subsamples from three depths:
- near the surface
- midway into the pile
- closer to the core (interior)
If you have multiple piles or windrows, sample them separately and submit separate composite samples.
Supplies you will need
- Clean auger, soil probe, or spade
- Clean 5-gallon plastic bucket
- Clean plastic tarp (helpful for mixing)
- Sturdy sample container (heavy zip-top freezer bag or wide-mouth plastic bottle), 1–2 quarts capacity
- Permanent marker for labeling
Step-by-step
- At the first location, collect about 1 pint from each of the three depths (surface, mid, core). Put all material into the clean 5-gallon bucket.
- Repeat at each sampling location, adding all subsamples to the same bucket.
- Mix thoroughly to make the material as uniform as possible.
- Mixing is often easier if you dump the contents onto a clean tarp, mix well, then return it to the bucket.
- Take the composite sample from the well-mixed material.
- Submit about 1–2 quarts, depending on the analyses requested.
- Package and label the sample clearly (sample name/ID, pile or windrow ID, date collected).
- Complete the SNAL compost submission form and include any required payment information as indicated on the form.
Drop off the sample at the lab directly or mail it promptly so the sample arrives quickly at the center. Shipping early in the week helps avoid weekend delays.