Every year, starting in the fall (October-ish), I get clusters of emails from frustrated PermaClone customers that are NOT newby's, while they're experiencing major delays in root formation along with increased failures. The initial dialogue is frustrating as I work through questions relevant to a novice grower before finally realizing they have the "fall stall".
The fall stall is due to the conditions of your mother space when the outside temperatures drop, while your veg space is dialed to keeping things cool throughout the year. The plants still do 'OK' overall, but are simply not tuned for cloning. The symptoms often go overlooked, but if you learn to notice them, you will speed up your winter cloning and, hopefully brings some holiday cheer.
Here are a list of the symptoms you should look for that indicate your plants are experience this stall.
- Slower growth
- Woodier Growth. new growth becomes less supple and woodier
- Purple striping on the stem. Your plant will transition to growth with purple streak on the stem and petioles.
- Purple/red petioles. This type of purple or red formation should show itself around teh whole petiole and applyto petioles that are not exposed to your ligths. I mentione dthis, b/c sometimes the upper most petioles will become red on their light-exposed side due to light intensity, and not b/c of ambient temperature drops. Some petioles will get red on their top-side from being near bright lights...a sort of anthocyanin sunburn. This doesn't indicate things are too cold. Your looking for purpling/red petioles all and on petioles that are shaded.
- Root zone temps of <65 F (18 C)
- Ambient temperatures <72 F (22 C)
How to fix the issue:
- Insulate the roots from the floor
- Upside-down plant saucers
- R-max between roots and floor
- Increase ambient temperature to upper 70's and 80's. Before adding heaters, try some of the suggestions below to achieve added benefits to warming up the space.
- Dehumidifiers. dehumidification is often very much needed in the winter b/c your A/C is cycling less. Dehums give off heat while filtering your air and dehumidifying. This offers some efficiency.
- HPS Lights: if you've switched to some of the more efficient lighting systems (such as LED, CMH, etc) you may consider running some HPS in Fall and winter so you can boost the heat and IR output while adding light spectrum.
- CO2 Burner are an option, but there are concerns with ethylene and moisture coming from these, hence it's a option I promote second to last.
- Space heaters are my last recommendation b/c they are specifically wasting electricity to produce heat.
Why does this happen?
I've often talked about slower cell division at lower temperature and that may be involved, but the change in plant morphology mimics symptoms of Potassium and Magnesium deficiency. A quick literature search seems to validate the idea that imbalance in mineral nutrition happen when root zones are cold. I hope to learn more about this phenomenon, but for now my focus is preventing the "Fall Stall".
If you have any thoughts, please feel free to reach out. I'm releasing this post w/o much editing, so you may see this post evolve over time.
Thanks for reading and supporting PermaClone! Always feel free to reach out to me directly through our websites' contact form.