Soil sampling requirements in Hawaii

Q: How often do you need to soil sample in Hawaii?

University of Hawaii CTAHR, guide to soil testing (official guidance): At least once every 2 years.

Q: When in the year should soil be sampled in Hawaii?

University of Hawaii CTAHR, guide to soil testing (official guidance): Two to three months before planting.

Q: How many acres can one soil sample cover in Hawaii?

University of Hawaii CTAHR, guide to soil testing (official guidance): Larger areas such as pastures or orchards: uniform soil-test areas of 1 to 5 acres each.

Q: How deep should soil samples be taken in Hawaii?

University of Hawaii CTAHR, guide to soil testing (official guidance): 4 inches for no-till fields and established pasture. 8 inches for conventionally tilled fields. Tree crops 0 to 8 inches plus a subsoil sample from 8 to 24 inches.

Q: How many cores go into one soil sample in Hawaii?

University of Hawaii CTAHR, guide to soil testing (official guidance): 10 to 15 subsamples per composite sample.

Q: How many soil samples does a 100-acre field need in Hawaii?

Under University of Hawaii CTAHR, guide to soil testing: A uniform 100-acre field needs at least 20 composite samples of no more than 5 acres each, and at least 200 cores in all, 10 per sample.

State guidance: University of Hawaii CTAHR, guide to soil testing.

Soil sampling in Hawaii: frequency, area, depth and cores

How often do you need to soil sample in Hawaii?

University of Hawaii CTAHR, guide to soil testing Official guidance At least once every 2 years.

When in the year should soil be sampled in Hawaii?

University of Hawaii CTAHR, guide to soil testing Official guidance Two to three months before planting.

How many acres can one soil sample cover in Hawaii?

University of Hawaii CTAHR, guide to soil testing Official guidance Larger areas such as pastures or orchards: uniform soil-test areas of 1 to 5 acres each.

How deep should soil samples be taken in Hawaii?

University of Hawaii CTAHR, guide to soil testing Official guidance 4 inches for no-till fields and established pasture. 8 inches for conventionally tilled fields. Tree crops 0 to 8 inches plus a subsoil sample from 8 to 24 inches.

How many cores go into one soil sample in Hawaii?

University of Hawaii CTAHR, guide to soil testing Official guidance 10 to 15 subsamples per composite sample.

How many soil samples does a 100-acre field need in Hawaii?

University of Hawaii CTAHR, guide to soil testing: A uniform 100-acre field needs at least 20 composite samples of no more than 5 acres each, and at least 200 cores in all, 10 per sample.

Samples and cores for any field size

Soil sampling rules in Hawaii, with the exact wording of each source
Country / region	Purpose / programme	Time / frequency	Area per sample	Method	Depth	Cores	Status and source
United States
HawaiiUnited StatesHawaii only. Other states set their own rules.	Routine soil fertility samplingUniversity of Hawaii CTAHR, guide to soil testing	Repeat At least once every 2 years Season Two to three months before planting	Larger areas such as pastures or orchards: uniform soil-test areas of 1 to 5 acres each	Map the area into uniform test areas; separate samples for different slope, soil color, drainage, texture or cropping history. Cores taken at random, for example in a zigzag.	4 inches for no-till fields and established pasture. 8 inches for conventionally tilled fields. Tree crops 0 to 8 inches plus a subsoil sample from 8 to 24 inches.	10 to 15 subsamples per composite sample	Official guidanceUH CTAHR, A Guide To Soil Testing For Hawaii’s Residents
Who it applies to, the exact wording and every source Who it applies to Advice for Hawaii farms, pastures, orchards and gardens from the University of Hawaii College of Tropical Agriculture and Human Resources. Not law. In force from Under review Legal text University of Hawaii at Manoa CTAHR, A Guide To Soil Testing For Hawaii’s Residents (Hue, Uchida and Ho) The wording in the source Timing Soil in fields or gardens should be tested at least once every two years. How to take a representative soil sample Plan to collect soil samples two to three months before planting How to take a representative soil sample Area per sample For larger areas like pastures or tree orchards, first make a detailed map of your area, then divide your map into smaller uniform soil-test areas of a few (1-5) acres each. How to take a representative soil sample Method Fields with different slope, soil color, drainage, apparent texture (for example, heavy, light, or A’a) or cropping history should be sampled separately. How to take a representative soil sample Each sample to be tested should be a thorough mix of the cores taken randomly, say, in a zigzag pattern as shown in Figure 1. How to take a representative soil sample Depth Soil subsamples consist of 1-inch thick slices of the soil taken to a specified depth, normally 4 inches for no-till fields or established pasture, lawn and turf and 8 inches for conventionally tilled fields. How to take a representative soil sample For tree crops (forests, nuts, tree fruits), where possible, collect a surface sample to a depth of 8 inches and a sub-soil sample from 8-24 inches deep. How to take a representative soil sample Cores A soil-test sample for each area should be a composite of 10-15 subsamples. How to take a representative soil sample Sources UH CTAHR, A Guide To Soil Testing For Hawaii’s Residents Guidance Sources re-checked every two months, last update October 2026. Reviewed by GeoPard editorial team.

United States: federal rules and every other state

Soil sampling regulations in every country

Report an outdated requirement: info@geopard.tech

Plan the points to the rule that applies

Set the area per sample, the cores and the depth your rule asks for. GeoPard places the points on a grid or by zone, routes the walk, prints the labels and takes the plan to the field on a phone.

Create a sampling plan See the Soil Sampling Planner

A planning reference built from official sources, not legal advice. Rules apply by jurisdiction, nutrient, land use and programme: check the current official text and your laboratory’s instructions before fieldwork.

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Soil sampling requirements in Hawaii

Soil sampling requirements in Hawaii

Soil sampling in Hawaii: frequency, area, depth and cores

How often do you need to soil sample in Hawaii?

When in the year should soil be sampled in Hawaii?

How many acres can one soil sample cover in Hawaii?

How deep should soil samples be taken in Hawaii?

How many cores go into one soil sample in Hawaii?

How many soil samples does a 100-acre field need in Hawaii?

The wording in the source

Timing

Area per sample

Method

Depth

Cores

Sources

Plan the points to the rule that applies

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