Nutrifor: Sustainable growth supplement for houseplants?
Like many during the pandemic, I got really into houseplants. Like, really into houseplants. I’m still in the thick of it by any sane person’s standards but have significantly geared down to maintaining my collection rather than growing it.
With the funds freed from endlessly purchasing the next addition to my collection, the quest became: How do I grow my plants bigger faster?
My aroid collection enjoys a soil mix comprised of 50% coco coir, 30% orchid mix (bark, charcoal, and chunky perlite), and 20% perlite. My fertilizer routine was quite simple, Schultz 15–5–5 Orchid Food every watering with a Gardenwork’s 20–20–20 fertlizer monthly. Recently, I’ve delved further into testing products such as SuperThrive, CalMag, Marphyl, silica, and probiotics to extract further growth and health out of my plants. Still missing from my routine are slow release type fertlizers, such as worm castings or osmocote.
For that reason, I was excited to be able to get some Nutrifor at a promotional event. Nutrifor is a slow release type fertilizer composed of organic material remaining from the treatment of wastewater (biosolids) in the Metro Vancouver Regional District. These biosolids are further treated at high heat and broken down by microorganisms to meet regulatory standards before being mixed with sand and other materials to create Nutrifor.
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What about Nutrifor for houseplants? It seems like little has been done and it is uncertain if it would be effective in this application. With a large amount of Manjula Pothos (Epipremnum aureum ‘Manjula’) cuttings rooting at home, this was the perfect opportunity for some hobbyist science!
Methods
Six cuttings of Manjula pothos (Figure 2) were split into pairs based on the following classification: big, small, and low roots (Table 1).
These cuttings were potted in a soil mix comprising of 60% coco coir and 40% orchid mix purchased from Figaro’s Garden. For the Nutrifor experimental group, a 1/2 inch application of Nutrifor was added on top (Figure 3).
These were kept in a non-climate controlled cabinet with a grow light providing 6000 lux / 600 fc (as measured with the Lux phone application) between 8:30am to 8:30pm. Watering was conducted as needed with Schultz 15/5/5 fertilizer added.
Results
Well, did it work? Surprisingly… yes! A significant increase in growth rate was observed for the experimental group with the Nutrifor applied. Even a small 1/2 inch application to the top of the pot was enough to have a significant effect on the growth rate of the experimental group (Figure 4) and the effect is quite apparent in the time-lapse and side-by-side comparisons (Figure 5 and 6). In addition, we can see the effects of nutrient deficiency beginning in the control group as new leaves start to come in smaller and deformed.
Confounding Factors
There are some confounding factors to discuss before establishing conclusions:
- Variegation: Variegated plants have reduced growth rates compared to that of their non-variegated equivilants as a result of the non-photosynthetic white tissue. Differences in growth rates may be affected by the amount of green tissue in the plants at initiation.
- Coco Coir: This substrate is a sustainable equivilant to the use of peat moss. However, it presents two challenges compared to conventional soil types: a complete lack of nutrients and Cal-Mag lock out. Thus, the control group in this experiment completely lacked access to micro-nutrients.
Conclusions
Despite the confounding factors and small sample size, I think the effect size is significant enough to establish that a soil amendment of Nutrifor is, at the very least, effective at delivering micro-nutrients to houseplants. It also highlights how nutrient deficient Coco Coir is as a substrate and the neccessity of a fertilizer routine that includes micro-nutrients and Cal-Mag; something that is completely omitted when individuals suggest it as a sustainable alternative to peat moss.
Of course, I am not particularly happy with the confounding factors. In the near future I will do another trial using Monstera adansonii or Scindapsus pictus and use a regular potting soil to see if Nutrifor would provide benefits in a more nutrient replete environment.
