By Ron Alexander
Bloom gets inquiries from customers interested in planting directly in Bloom without an additional soil medium. Sometimes it’s to avoid the time and money of acquiring an additional base soil product when filling up a raised bed, or they are accustomed to using compost as a planting medium; occasionally the word “soil” in the Bloom URL also leads to confusion.

The Bloom™ Woody and Sandy Blend products were developed with specific end uses in mind. Woody Blend was initially developed as a compost alternative, to be applied at similar application rates as compost. Since then, we have determined that lower application rates of this product can yield good results. The Sandy Blend was initially developed as a topdressing for turf maintenance and reseeding projects. Since then, the product has been used successfully in planting bed establishment and renovation. And there are customers (including landscape and garden professionals) who have “gone rogue” and planted in Bloom’s blends against our recommendations and reported good results. So, knowledge of our products’ uses and applications continue to evolve with the benefit of customer experience and research.

However, here are a few reasons why we still do not recommend that you do not plant directly into Bloom’s blends:

  • First and foremost, as we hadn’t envisioned either product used as a direct planting medium, we are quite simply erring on the side of caution. Bloom does not have enough test data on either product as a planting medium to be comfortable making this recommendation.
  • The Woody Blend does contain a significant amount of nitrogen, including some ammonia-based nitrogen. Plant species that are lighter feeders (requiring less fertility), such as woody ornamentals, may be negatively affected by the excess nutrients. This was the case in a recent small-scale research trial, where two woody ornamentals fared poorly after being planted in pure Woody Blend, while two annual plants did fine.
  • Sandy Blend, on the other hand, contains fewer nutrients and is more biologically stable, like soil, because it contains sand. While its content of Bloom, hardwood fines and sand makes it resemble a container media, we have not completed any trials using this product as a direct growing media.

So as much as we would like to suggest these two popular products be used as stand-alone growing media, we (like doctors) first have to do no harm. As our product knowledge continues to evolve, hopefully in time we will be able to provide more confident input on which types of plants like to be directly grown in Bloom™ Woody and Sandy Blend.