Composts & Media Testing

Media Testing

A testing programme to analyse composts and growing medias for their nutrient content is available. Additional tests for organic growers are also offered.

About this Testing

What are Composts and Medias

Soil-less growing media are used directly as a complete growing media for the plants to grow in. Likely ingredients of soil-less growing medias are fine bark or peat with pumice or untreated sawdust with slow release fertilisers. At Hill Laboratories, materials other than growing media will be regarded as composts.

Compost is a material added to a soil as a mulch or soil conditioner to add valuable soil organic matter. Composts are often dug into the soil to improve soil drainage, aeration and nutrient holding ability.

Please Note: Other than dairy effluents, raw manures are not accepted by the lab.

Basic Media Testing

Almost all of the growing media received at Hill Laboratories are analysed for the Basic Media Test. This test includes pH, Electrical Conductivity and the immediately plant available nutrients ammonium-nitrogen, nitrate nitrogen, phosphorus, potassium, calcium, magnesium and sodium.

Additional Media Tests

  • Trace Elements

The trace elements iron, managanese, zinc, copper and boron are analysed. As with soil trace element testing, there are limitations to the reliability of testing trace elements in media samples. In most instances, suspected trace element problems should be confirmed with plant tissue analysis.

Taking a sample

  1. Take at least 15 to 20 representative sub-samples from different areas of the potting media.
  2. Approximately 0.5 litre of media should be submitted for analysis. If trace elements and NDI are also required, please submit 2 litres of potting media.
  3. Avoid contamination of samples by using clean sampling equipment and bags.
  4. Send samples to the laboratory as soon as possible. Do not allow mixes to incubate in moist conditions for long periods prior to submission.
  5. Where intensive cropping is involved, it may be advisable to monitor nutrient levels by sending samples for analysis every 3 to 6 weeks.
  6. If a nutritional problem is suspected, plant tissue samples should be taken in combination with media samples.
  7. If diagnosing a specific problem, select a representative sample from pots showing the most prominent symptoms.
  8. Media & Compost Request Form

How to Order a Test

Complimentary Soil and Plant Test Kits for submitting media samples are available from the laboratory. These sample kits contain instructions, an analysis request form, sampling bags and courier bag to send in the samples.

Guides and Supporting Information


Contact Us

Freephone 0508 HILL LAB (44 555 22) or email