Terrarium growing experiments - Page 15 - Orchid Board

Metallising · #**141** 04-20-2021, 07:14 AM

Nice progress !
Next order from ecuagenera will include a Trisetella andreettae like yours

2 questions related to your setup Draikan:

1 - Any clue on how much light intensity your plants are receiving? In my terrarium most plants are getting 600-1000 foot candles of cheap 6500k LED lights for 10h. Would like to hear your numbers.

2 - I believe I read in some previous post you apply fertilizer through the misting system. Any issues with clogged nozzles ?

I finally found my 13~ years old arduino board, let's get started!

Draikan · #**142** 04-20-2021, 01:56 PM

My light meter says 200 foot candles near the bottom of the tank and 500 near the top. I run the light 12 hours a day. Most of my plants aren't happy at the top of the tank, and would rather be at the middle or lower layer.

Yes I do put fertilizer in the irrigation water. When I recovered the tank from my parents after ~1.5 years, the nozzles were very slightly dirty but still functioning. I'm not sure if they were actually corroded. Rather, I think that as the last drop of water from a mist cycle evaporates off the nozzle, it leaves a tiny bit of stuff behind. Overtime this may build up.

I have changed the schedule to mist two times for about 1 minute each, 10 minutes apart, on watering days. This way the nozzle can sit in fresh water for 10 minutes before running again. I've only been doing it this way for a few months, so it's a bit too early to be sure, but it seems to really help dissolve then flush anything that was left in the nozzles on the previous cycle. I was actually doing this to help the plants soak then flush, but it seems like it might be good for the nozzles too.

Good luck with the Arduino!

Metallising · #**143** 04-20-2021, 07:08 PM

I have read when growing Masdevallias and other low light orchids one should aim to around 1000 foot candles. However, I'm leaning to agree with you, most species seem to be doing better with less light, those getting 600 FC look better than those getting 1000 FC.

Regarding the nozzles nice to know it doesn't clog frequently.
As part of maintenance schedule, the nozzles could be submerged in cleaning vinegar (acetic acid) a few minutes every 2-3 months, it should dissolve the build up of any minerals.

Draikan · #**144** 04-20-2021, 08:00 PM

Yes I agree, the plants I'm growing tend to need less light than recommended. I suspect many of the old lighting recommendations do not translate well to LED (especially when made in units like foot candles or lumens which make assumptions about the spectrum of the light which are inaccurate for LEDs).

I have generally noticed two different behaviors from plants in my tank that get too much light.

Some plants are more tolerant of high light and tend to progress like below when exposed to increasing light:

dark green>green>pinkish>purple

I think I've noticed that these tend to have pink hues/streaks/spots in baby leaves as they emerge.

Others that tend not to tolerate bright light so well go:

dark green>green>yellow>burned

I don't think I've seen the purple notes in baby leaves of these species.

But of course there are exceptions. I had my M. nidifica in a brighter spot for a while, and it basically went dark green>purple/brownish>burned. This one seems very sensitive to bright light.

I'll try to get some pictures of what I mean by the purpleness in new leaves later.

I generally just aim for light green in all foliage now, unless it's a plant I know can handle brighter light like P. alenii.

Cleaning the nozzles would be a great bit of preventative maintenance for me to do a few times a year. My nozzles are cheap metal ones too, so it may be even more helpful. I doubt the plastic mistking nozzles would have any issue with fertilizer solution at the concentrations we are using.

Roberta · #**145** 04-20-2021, 08:08 PM

I suspect that many of those that go purple in high light have red or purple flowers - anthocyanin tends to be lurking in the leaves when the flowers have the pigment. The ones where they can't develop a "suntan" just fry. Like light-skinned people.

Draikan · #**146** 04-20-2021, 08:43 PM

Quote:

Originally Posted by Roberta

The ones where they can't develop a "suntan" just fry. Like light-skinned people.

Oh that's me.

Metallising · #**147** 04-20-2021, 09:06 PM

True, most recommendations on light intensity are probably based on fluorescent light or sunlight, which include green spectrum. Those numbers shouldn't translate well to modern LEDs with higher photosynthetic active radiation (PAR).

I recognize the green>purple pattern in my plants too. However I'm not 100% positive it is only related to light intensity, I suspect it may be related to temperature as well. My theory is that when temperature drops more than the plants are used to, their photosynthetic activity is reduced and less light is needed.
From my observations it seems during Winter I have more purple leaves than during Summer, growing with the same light intensity year round.

I have two M. nidifica growing in the 600-800FC range. They flower very well but they definitely have lots of purple hues, some leaves are totally purple, not sure if it means they are about to burn but guess not as I don't see any leaves falling.

In general it takes some time for me to learn the light requirements of newly acquired orchids, the symptoms are not always clear.

Metallising · #**148** 04-21-2021, 08:37 AM

I'm about to start programming my arduino. I want to be able control temperature / humidity and keep these parameters between a specific range. For this purpose I will use sensors connected to the arduino reading the environment and then control a fan, misting system, heating cable and peltier cooling system based on a serie of rules.

I'm not sure how I will put this into a program yet, neither all hardware needs but this is how I want the system to work.

I'm hijacking Draikan's thread again to share my ideas but I think it makes sense to post it here to have all ideas related to automation in one place.

A quick sketch with a few ideas for the program:

Day cycle starting at 10am

- turn on lights

- turn on misting system for 1 minute
- turn off fan while misting (so the droplets don't go into the fan bearings and water trajectory is smoother).
- after misting turn on fan at 100% power for 4h, after that adjust power to 40%.

- read temperature (target temperature 23-27C)
- if temperature below 23C, turn on heating cable. (It is currently buried in the substrate of my terrarium, pulls 20W). When temperature reaches 23C stop heating.
- if temperature above 27C turn on peltier cooling system. Allow temperature to drop 1C and turn off.

- read humidity
- if humidity under 80%, turn on misting system for 5 seconds.
- read humidity once per minute, so the misting system will be activated again for 5 seconds in case humidity still low.
- if humidity higher than 95% adjust fan power to 80%

at 3pm

- turn on misting system for 1 minute

(all the previous rules still apply).

Night cycle starting at 8pm

- turn off lights

- Calculate average day temperature (target temperature at least 4C lower than average day temp.)
- wait until 12am for terrarium to cool of a bit after lights off, then start reading it's temperature.
- If temperature drop at least 4C compared to average day temperature: do nothing
- if temperature drop is inferior to 4C turn on peltier cooling system.
- Keep this rule active from 12pm to 6am (the peltier cooling system consume about 70W, I want this project to have low costs.)
- if temperature below 14C, turn on heating cable. (More likely this won't happen too often in my living room where the terrarium is...)

Ideally I would like temperature to drop a bit more during night cycle but that won't be feasible for now unless lots of complexity and costs are added into the equation.

Draikan · #**149** 04-21-2021, 01:26 PM

Metallising, it is awesome that you are going to experiment with some automation. I have a couple tips for you that have been critical to my progress so far.

Break the project into tiny, tiny pieces. I mean REALLY tiny. "Measure temperature" is a good example of a manageable task. Add each little bit of functionality and test the individual pieces very carefully before trying to put them together. It's very difficult to find errors as the system becomes larger and more complicated.
Setup a test tank with plants you don't care about to work in while you get the kinks worked out. There will be all kinds of little mistakes and bugs that do silly things like run the mister for an hour instead of a minute, or never turn the heater on. A plastic rubbermaid tub is fine.
Don't try to heat the air until you have both humidity and airflow under control. Temperature directly changes the humidity, so as soon as the air temperature starts to rise humidity will start to drop.

Are you talking about a ventilation fan, or circulation? Remember that you can get waterproof fans. Look for one with an IP rating like IP67. It can be hard to find smaller waterproof fans, but this is easily solved by building the terrarium as big as possible

Metallising · #**150** 04-21-2021, 02:51 PM

Thank you for the tips !

You are right, better to break the project into little steps, I'm expecting a long walk. A few years ago I used an arduino with movement sensors, microphone input and light sensors for an interactive artistic installation, in the meanwhile I forgot most details but with Google this days won't be hard to re learn.

I only have one fan installed, a cheap 120mm circulating fan. True I can get waterproof fans but not sure it's worth the extra money for now. Main issue in my terrarium is how the airflow from the fan influence droplets trajectory while misting, spreading water everywhere but plants, I tried different nozzles from 3mm to 5mm but the problem maintains. Your terrarium is bigger than mine so you probably don't experience the same issues as you have more space between the nozzles and fan.

While my terrarium is not digital automated it is analog automated somehow. In practice the program I want to write will basically just replicate what is already happening, I have the fan, misting system and heating cable already operating, only the peltier module is missing.
My terrarium is currently running on timers (1 second interval timers!!) and inkbird temperature and humidity controllers, it allows me to keep things under control but I want to integrate digital automation to be able to introduce finer adjustments and make the system a bit smarter.

Plus, the amount of gear and power sockets I'm using to automate is ridiculous comparing to what can be done with a palm size arduino and a couple of sensors.

On a side note, I think it's worth checking on Inkbird controllers for those looking for some automation but don't want to go into microcontrollers and nerd stuff. Reliable equipment widely used in mushroom cultivation and homebrewing.

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