Kimberly Moore, an associate professor in the Environmental Horticulture Department at the University of Florida, has spent parts of the last four years evaluating a product called Densu Coir, an organic and soiless substrate that’s produced from coconut husks. Moore shares her observations of Densu Coir and a summary of its performance in her research below:
Densu Coir Summary
In each case, we grew the plants in 100 percent Densu coir. The peat-based substrates were blends of approximately 60 to 80 percent Sphagnum peat with perlite, vermiculite, etc. All comparisons were unbiased experiments. Results presented do not constitute an endorsement of this product.
2009/2010
Densu coir was one of three substrates used to grow Jatopha curcas, a potential biofuel crop. Jatropha plants grown in containers with coir were comparable to growth in containers with peat-based substrate. This study is being published in HortTechnology this year.
October 2008
Densu coir was one of two substrates used to grow dieffenbachia plants. Average shoot dry weight of plants grown in Densu coir was 27.4 grams and average shoot dry weight in peat substrate was 27.3 grams.
March 2008
Densu coir was one of two substrates used to grow calathea. The fertilizer rate refers to controlled-release fertilizer incorporated into the substrates at low, medium and high recommendation rates on the fertilizer label for this type of plant
| Fertilizer Rate | Densu Coir (100%) | Peat-based Substrate |
| Low | 28.6 | 24.7 |
| Medium | 28.9 | 25.9 |
| High | 30.3 | 27.8 |
| Average | 29.3 | 26.3 |
March 2007
Petunia plants were grown in Densu coir, peat-based substrate or bark/sand substrate. A rating of 3 or higher was considered saleable. (1=dead, 3 = saleable, 5= superior). The first table below is a rating and the second table below is shoot dry weight. The fertilizer rate refers to controlled-release fertilizer incorporated into the substrates at low medium and high recommendation rates on the fertilizer label for this type of plant.
| Fertilizer Rate | Densu Coir (100%) | Bark/Sand | Peat Based |
| Low | 2.3 | 2.1 | 2.9 |
| Medium | 3.2 | 2.8 | 4.8 |
| High | 3.5 | 3.0 | 1.0 |
| Fertilizer Rate | Densu Coir (100%) | Bark/Sand | Peat Based |
| Low | 0.31 | 0.23 | 0.58 |
| Medium | 0.56 | 0.65 | 1.31 |
| High | 1.09 | 0.59 | 0.10 |
Advantages of Densu Coir
• Easy to work with
• Plant growth in 100 percent Densu coir was comparable to other substrates evaluated as long as fertilization was included. It works well with controlled-release fertilizer products applied as top-dress or incorporated into the substrate
• Wets easily and quickly; also re-wets easily if plants dry out between watering
• High moisture content
• Less dust when dry (easy of mixing and handling when dry)
Disadvantages
• Crop growth might vary; crops that grow well in peat-based substrates appear to grow equally as well in Densu coir.
• You have to add nutrients to the media to get good crop growth.
• Leachate solutions collected were very dark; hard to take accurate phosphate readings because leachate was dark brown.
The work summarized above does not imply an endorsement of this product. All studies were unbiased trials. The data is a fair representation of how the plants tested grew in various substrates. Results may vary with other plants as well as under different growing environments. From the data we have collected, Densu coir appears to be a good substrate for growing a variety of plants.