Saturday, April 19, 2014

Dog Hair as a Rooting Medium


Dog (Canis familiaris) hair is cheap, abundant, renewable, and produced in such vast quantities that one feels mortally certain that it must be good for something besides canine thermoregulation. Furthermore, most existing rooting media are dependent on the destruction of natural ecosystems (peat moss), require a large amount of energy for production (perlite), or pose a health hazard to the producers and users (vermiculite),1 so finding a more renewable medium would be a boon to both plant-loving dog owners and the environment.

As canine hair has some qualities in common (holds water, fibrous texture) with other substances used in rooting media and soilless potting mixes, it was evaluated for its potential as a rooting medium.


The floor of a home containing a dog ("Sheba," Fig. 1) was swept, and the sweepings collected into a pile. (Fig. 2) The sweepings were then separated into hair and non-hair, with the latter discarded. (Fig. 3) The material which resulted was fibrous and mostly dark gray in color, with inclusions of lighter matter.2

Fig. 1 ("Sheba")

Fig. 2 (material collected by sweeping)

Fig. 3 (collected material post-purification)

The hair was then added to a plastic pot, 7 cm in diameter. Non-hair material was left out of the pot when it was feasible to separate it. Once the hair had been placed in the pot, it was rinsed with water several times to remove water-soluble contaminants. (Fig. 4)

Fig. 4 (rinsed hair in pot)

Next, the cutting to be rooted was prepared. We selected Plectranthus verticillatus (Fig. 5) as a test subject, because P. verticillatus is known to root readily under a large range of conditions. A cutting approximately 7 cm in length was taken from a plant (Fig. 6), and the lowest pair of leaves was removed.

Fig. 5 (the stock Plectranthus verticillatus plant from which cutting was obtained)

Fig. 6 (Plectranthus verticillatus cutting before removal of lowest pair of leaves)

After making a hole in the dog hair at the center of the pot, the end of the cutting was placed into the hole, and the hair packed around the stem to ensure contact between the rooting medium and the cutting. The pot was then placed in a brightly-lit but sunless location. Moisture level was monitored, and water added when it would have been added for a cutting rooted in soil.


During the first full watering, a considerable amount of dark brown material washed out of the rooting medium. Chemical characterization was not performed, and the identity of the substance is unknown. Similar but lighter yellow material was washed out of the medium following some but not all subsequent waterings.(Fig. 7) Rooting medium had no discernible odor.

Fig. 7 (drainage water containing uncharacterized yellow contaminant)

The experimental pot retained water much longer than a comparably-sized pot of standard potting mix. However, the distribution of the water was quite different. The upper half remained relatively dry, even immediately following the addition of water, while the lower half stayed very wet. This made it difficult to determine when to water the cutting.

The oldest pair of leaves wilted significantly after three or four days. No new leaf growth was observed; a few small (< 2 mm) roots had formed by four weeks (Fig. 8). This is significantly less root growth than would have been expected from potting soil or water after an equivalent length of time.
Fig. 8 (roots formed after four weeks in rooting medium)

After five weeks, the cutting remained alive but wilted, and had produced no new growth. (Fig. 9)

Fig. 9 (cutting after five weeks in rooting medium)


Though root development suggests that canine hair may be capable of rooting plant cuttings under some circumstances, development was slow compared to standard media, probably due to the different water-absorbing abilities of canine hair, and it is likely not an acceptable substitute for potting soil.

This experiment also demonstrates that Plectranthus verticillatus, contrary to popular perception, is not in fact capable of rooting in any material, merely in most of them.


1 Large-scale production of canine hair also results in the indirect destruction of natural ecosystems and consumes considerable energy, in addition to generating significant amounts of ecologically problematic waste. Objective observation of human behavior to date with respect to animal companions leads us to conclude that humans simply do not give a shit about the ecological impact of their pets, and would continue to attempt to keep domesticated dogs, cats, hamsters, etc. even if forced to live in a poisoned, radioactive, waterless hellscape as a result, because they are adorable and precious, whoosa good dog, whoosa good dog yes you are. If humans are to keep animals as pets in any case, we may as well figure out how to do so in as minimally disruptive a manner as possible.
2 The inclusions were primarily composed of household dust, lint, fragments of potting medium from indoor plants, and the fallen leaves of said plants.


Ginny Burton said...

Wonderful post! I had no idea that a short-haired dog like Sheba could shed so much. Or do you not vacuum very often?

Anonymous said...

Love this post. Reminds me of the time I collected used cigarette filters and added them to potting soil to see if they might add moisture retentive properties to the soil medium. It worked, but...........

Texas anon

Liza said...

Whoosa good blogger? Whoosa good blogger? Haha, I couldn't resist.

I love this experiment, I hope you do more.

I was researching how to deter rabbits from eating vegetable gardens for a client, and people kept recommending dog hair. Apparently putting dog hair around the perimeter of a garden sends a message to most critters to stay away. So maybe if you can't use the hair as a potting media, there are still plant-related uses to explore????

I didn't know before that I was such a big fan of creative uses of dog hair.

Paul said...

Bryophyllum daigremontianum might have had more success as it seems to root even with no media.

A further line of experiments would be the inclusion of dog hair as an additive in various media.

mr_subjunctive said...

Ginny Burton:

Upstairs, we don't vacuum at all, because it's all wood floors.

I am supposed to sweep the upstairs once a week, but I don't always manage that. Sheba doesn't actually shed that much, but she sheds enough that the hair starts to be visible after about a week. (And even if she didn't, potting soil winds up on the floor too, so I'd have to sweep about as often even if we didn't have a dog.) I don't remember for sure, but I think this post followed a stretch when I had missed a week, so the collected hair was about twice the usual amount.

Downstairs, where there is carpet, is a whole different issue, mainly because our vacuum cleaner doesn't work well. But Sheba spends a lot less time down there, and the carpet is pretty nearly the same color as Sheba, so it's not a critical problem as often.


I think I've pretty well done that experiment already without meaning to: every time I knock over a plant and have to sweep the potting soil back up again, I wind up adding dog hair to the pot. It doesn't seem to be making a noticeable difference to anything, but I haven't been keeping track of which plants have it and which plants don't, so I can't make direct comparisons very well.

danger garden said...

Oh that was fun, kind of reminds me of our neighbor who was knitting a sweater from her cat's hair. Kind of.

Ivynettle said...

This is hilarious!

We sell a fertilizer made of pig's bristles, so maybe dog hair would work as well?

Paul said...

Ivynettle, didn't you mean "HAIR-larious". :D