When to sample

From the perspective of nutrient availability, soil can be sampled any time of the year as nutrient levels vary only slightly from season. A small decrease in exchangeable potassium may occur following a productive harvest, yet a field difference is unlikely to affect fertilizer recommendations.

Ideally, soil is sampled between crops such that corrective fertilizer and lime applications can be made before the next season. Although most producers take samples in spring, this is the time when our laboratories and county offices are overloaded with samples. A delay in the return of results may occur. Fall or winter sampling leaves more time for planning and corrective fertilizer management.


How to take a soil sample for horticultural or commercial crops

Divide the field into uniform areas
Soil samples should consist of uniform soil areas. Each area should have the same soil color and texture, cropping history, and fertilizer, lime and manure treatments. One sample should not represent more than 20 acres on level, uniform landscapes, or five acres on hilly or rolling land. Within each area collect 15 to 30 subsamples (cores, boring or spade slices) in a zigzag pattern throughout the sample area. The more variable the soil, the more subsamples should be combined per area samples. Mix the subsamples thoroughly in a clean plastic pail, and fill the sample box or bag to the fill line (one pint). If samples are collected wet, they should be dried before being mixed and submitted to the laboratory. Do not exceed a drying temperature of 97 degrees Fahrenheit, and do not use a microwave to dry the soil unless only the nitrate test is requested.

For commercial fruit and vegetable growers
Sample each area as follows: Scrape off all surface residue. Sample to a depth of 6 to 8 inches (plow layer) for cultivated crops or 3 inches for turf or sod fields. Sample row crop between rows, except for ridge-till plantings. Where ridge-till is used, take the sample to a depth of 6 to 8 inches on the "shoulder" of the ridge, avoiding the starter fertilizer band. Also avoid sampling dead or back furrows, terraces, old fence rows, lime or fertilizer spill areas, headlands, eroded knolls, low spots or small saline areas. Sample at least 300 feet away from gravel or crushed limestone roads because their dust changes soil pH.

For orchards and vineyards
At the time of establishment, it is recommended that both surface (0 to 6 inches) and subsoil (6 to 12 inches) samples are taken. After establishment only surface samples need to be taken.

Horticultural or commercial crops for which recommendations are given

Up to three crops with associated yields can be selected for each sample. So for each soil sample submitted you may get recommendations for apples, peaches and brambles. You may choose any combination of three of the crops listed in the table below.

Code Crop
Fruits - new plantings
1 Apples and pears
2 Blueberries
3 Brambles
Raspberries, blackberries, gooseberries
4 Grapes
5 Stone fruits
Peaches, plums, apricots, cherries, nectarines
6 Strawberries
Fruits - established plantings
7 Apples and pears
8 Blueberries
9 Brambles
Raspberries, blackberries, gooseberries
10 Grapes
11 Stone fruits
Peaches, plums, apricots, cherries, nectarines
12 Strawberries
21 Asparagus, new
22 Asparagus, established
23 Beans and peas
24 Beets
25 Broccoli
26 Brussels sprouts
27 Cabbage
28 Carrots
29 Caulifower
30 Cucumbers
31 Lettuce
32 Melons
Watermelons, cantaloupes
33 Onions, dry
34 Onions, green
35 Peppers
36 Potatoes
37 Pumpkin and squash
38 Radishes
39 Spinach
40 Sweet corn
41 Sweet potatoes
42 Tomatoes
Turf - establishment
61 Turf establishment or renovation
Turf - maintenance
62 Athletic field, cool season
Bluegrass, fescue, ryegrass
63 Athletic field, warm season
Bermudagrass, zoysiagrass
64 Commercial sod, cool season
Bluegrass, fescue, ryegrass
65 Commercial sod, warm season
Bermudagrass, zoysiagrass, buffalograss
66 Low maintenance turf, cool season
Bluegrass, fescue, ryegrass
67 Low maintenance turf, warm season
Bermudagrass, zoysiagrass, buffalograss
Golf courses
68 Putting greens
69 Fairways, cool season
Bentgrass, ryegrass, bluegrass, tall fescue
70 Fairways, warm season
Bermudagrass, zoysiagrass
71 Tees, cool season
Bentgrass, ryegrass, bluegrass
72 Tees, warm season
Bermudagrass, zoysiagrass