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North greenhouse growers, are your wireless thermometer alerts ready?

October 18, 2018
last modified: October 18, 2018

Yes, it's that time of the year again. Can you believe it already? I have all of my plants in the greenhouse already and on a porch in which I rely on a wireless thermometer to give me readings quite often and alerts if the temperature or humidity should stray south of what I need.

I have my alerts set at every 15 minutes so that I know what the temperature is in there at all times, even here at work.

Twice last year during the middle of the night I was alerted of temps falling under 50 degrees and thank God I had it. I had to turn the heaters on after the power went out for some unknown reason even for a second.

If I had not been alerted, I would of lost everything in that greenhouse and on my porch.

One night, it was -0 and within 15 minutes the temps in there dropped to 33 degrees.

Are you prepared for this, and what system do you use?

I use the Ideal Sciences Alert system.

Comments (19)

  • katiebeth128_wv_6b

    Good timing on the subject, Mike.

    I just got an "Ambient Weather WS-8482-X3" for this year, supposed to be Alexa-compatible so I can just ask the app on my phone or other Alexa device what the measurements in the greenhouse are. I really like the idea of being able to have the data constantly logged and spreadsheet-able with weather underground etc. Yes, I am a data nerd.

    I think the alert notices like you mentioned are essential for peace of mind in the winter.

    I overwinter my citrus and subtropicals etc indoors in a large grow tent, but the figs, poms, turmeric, ginger, passionfruits, and various rootstocks are all in the greenhouse and I do worry about them often. The greenhouse GFCI outlet has tripped a few times before and that could be a disaster in the middle of winter, so I'm hoping this weather station will give me all the reassurance I need while I'm at work

  • rina_Ontario,Canada


    Could you please add your general location/growing zone to your name please? (see mike or most other members). It is easier to consider your growing conditions if known...

    Why do you use grow tent indoors?

    What kind of GH do you have? Is it freestanding? attached to the house? glass-plastic-or? What do you heat it with (electricity-gas-wood-oil...?)


    I hope you don't mind me asking questions bit off subject.

  • katiebeth128_wv_6b

    Hi Rina, absolutely I can. I thought I had it in my profile but I believe I was thinking of a previous account I had had on here or gardenweb.

    I grow figs, pomegranates, "Warm temperates" and cold temperate things in a freestanding, aluminum frame greenhouse that is heated a very small amount with a radiant oil heater, I usually keep it between 30-40f in the winter to ensure any chill hour requirements are met, but to avoid losses to winter conditions. I find the figs and poms really appreciate the extra protection from cold, dry wind, even though I have several friends that grow them without protection outside in the ground in WV near me (still 6B).

    It should be much easier to maintain the target temps in this outside greenhouse this year with a new, clear solar pool cover as a second skin (bubbles facing inward). I find that the temperatures inside my GH plummet as soon as there is no 'greenhouse effect' taking place, unless there is a huge amount of thermal mass to store the heat. I do have many more plants in it this year, so that should improve the conditions by holding onto more heat and releasing it at night, if only a little bit. Forgot to mention the outside GH has only a thin layer of poly film as a skin. Eventually, I will replace it with double walled rigid poly, but I will expand the GH structure first before I bother with a total re-skin of it.

    Back on topic, I'm kind of obsessed with recording the temperature data to confirm the impact that these improvements will have made to the greenhouse this year. I literally just ordered that weather monitor thing about two or three days ago so Mike had perfect timing with this thread. I used to record data like this by hand but it is just too time consuming, although I still miss the notebook as a medium it will surely save me lots of time with this upgrade.

    I prefer to keep the citrus 'lumped in' with all of my houseplants and subtropicals, because I don't want them to stop growing when the temperatures are too cold to sustain active growth. The lowest temperatures that I record inside the grow tent that they are in (which is in a backroom in an insulated garage) is ~58f in the winter, ~55f at the root zone on the coldest days. I'm already paying to heat the garage itself, so I keep the citrus etc in there in the large, 10x10 grow tent where I can maintain and fine tune temperature, humidity and other conditions much, much easier than the outside 10x20 greenhouse. Plus, if I can 'bottle up' that citrus bloom smell in a grow tent, inside where I can enjoy it in the winter, that is a huge plus. I think they are one of my favorite scents.

    Indoors, I'm logging a lot of statistics on root zone temperatures, growth, flowering, etc to see if there is much difference in growth rates between citrus cultivars, and at what temperatures and conditions these differences may occur. Depending on the citrus cultivar, the >55f root zone temperature often cited may be misleading, or a little too broad, depending on your goal of growing citrus or just overwintering them safely. Hopefully I'll have some valuable data come spring

    EDIT: woops, I'll include a picture of the greenhouse (before I moved the 23 non-hardy citrus into the grow tent) and also a pic of the grow tent with citrus etc in it. Also, I use LED lighting in the tent on a 16hr/day schedule so I apologize ahead of time for the hideous pink hue in the tent photo. Plants love it, though, and I'm loving not dealing with HID lighting anymore =)

  • tropicofcancer (6b SW-PA)

    Interesting Katie - keep updating. I have a 8x10 cold 'greenhouse' with no heat for temperate plants. In my shed this year I plan to house the figs/poms and a few others to over winter. I do not have a full weather station. But I have built several wireless programmable temperature monitors that log data to my desktop computer through wifi. Right now the only automation I have done is for the small 100W pond heater. The pond heater keeps a small hole open for the lone fish there. The probe is next to it in the water and the controller turns on/off the heater just to keep a small hole open. I plan to do the same in my shed (time permitting) to keep the temp just above freezing.

  • tropicofcancer (6b SW-PA)

    Cool pictures. My outdoor coolhouse is also built with EMT conduits like yours. The only difference is that I have a white 6mil greenhouse plastic sheet that cuts down 70% of the light to prevent large temperature swings. My potted maples and other temperates go in their. It is unheated. Your indoor setup is nice too. Which Led's you use. These days I am a big fan of the quantum boards from Horticultural Lighting group. They use white leds and are super efficient. But again it is a bit of DIY kit. I do have couple of the 'blurple' lights too but the color takes away a lot of the enjoyment for me.

    My indoor plants are largely in converted front porch. The conversion was mostly from salvaged material and craigslist sellers except the windows. This was early this year. My plan is to build wireless timers this winter so that I can also control them from my computer.

  • rina_Ontario,Canada


    Thank you for such detailed answer!

    I do not have such variety of big plants; but have 3 figs, few brugmansias; 3 olives; 2 loquats; passion fruit...there is always problem to overwinter them - I use unheated breezeway but wonder if that is too cold. I am not trying to keep them growing, just to overwinter. They loose leaves and go to sleep. I do not supply any extra light either, jus what comes thru the windows. Figs and some others were OK, brugmansias probably too cold - they all survived, but with quite a bit of dieback on branches and took a while to start growing in the spring...

  • rina_Ontario,Canada


    Cool! Is that your plant room that I think you posted photos "in progress of finishing" before? How warm do you keep it?

  • tropicofcancer (6b SW-PA)

    I do not think I ever posted a progress post but I did post pictures at various stages in various threads. It is still not entirely done but pretty close. May be this winter.

    It is attached to the house so it has some heat benefit. I do have a radiant electric heater that kicks in around 45F and turns off around 50F. Coldest I have seen it get to is about 40F without any supplemental heat. Next to the windows must be quite cold, close to freezing I would guess, when it drops below 0F outside.

  • isde02(zone5b)

    I'm using a growtent indoors as well. I'm just using a thermostat and large heat mats to control temperatures.

    I use the growtent because the room where most of my plants are has a drafty sliding glass door. Some of my plants are delicate and can't tolerate the cold drafts.

  • katiebeth128_wv_6b

    tropic, I thought about putting together a housing and using some of the newest gen samsung LED's (F series gen 3, I think) but decided against it, at least for right now.

    The first LED light I had is the one throwing off the purple-pink color in the photo, just out of sight. I think it is a "1200 watt". In practice maybe 300w while running.

    The newer light is the one I have over the citrus and it is a bit bigger than the purple-pink light, and I love it because it throws almost exactly the color of a metal halide light, maybe a little softer, and allows for much more color to be seen on the leaves etc. It's a BESTVA Reflector series 2000w. I want to say the LEDs have lenses that magnify so you can hang it further away from the plants. It's got a lot more UV and white LED's along with the usual red and blue.

    I don't think the picture I posted earlier really shows the colors well - I think the purple-pink from the other light is too much for my camera to compensate for. I know it's too much for my eyes to haha..

    isde02, how big are the heat mats that you use in your tent?

    I like using the grow tent to grow indoors. I find it makes it easier for me to keep conditions more constant in them. When I am not overwintering things inside the tent, it's being used for propagation and seed starting, too.

  • Vladimir (Zone 6a Massachusetts)

    The problem with using a battery operated WiFi alarm system like the Ideal Sciences unit (as I found out) is that a) it can stop working due to signal interference and b) the battery can die without notice. That is why I use a hardwired system with battery backup.

  • tropicofcancer (6b SW-PA)

    Katie, I was not trying to be critical of your setup. I also have a couple of the blue-red lights. They are useful and some plants seem to like it more. My lights are a mostly leds, some CFLs and one 2ft T5HO. The CFLs and T5 are for localized lighting. Till last year I also had a 600W HID which absolutely made the area Sun like white. The bulb blew out right when we were ready to take the plants out in late spring. Lucky for us. And so this year I researched a lot and thought I will give the new Samsung LED panels a try.

    From: https://horticulturelightinggroup.com/collections/quantum-boards/products/qb120-quantum-board

    I got two and hooked it up for trial and it is quite amazing amount of light for 120W actual consumption. I am going to get another pair with a bit higher power.

    Vlad: For low temp usages Lithium batteries are more reliable. But the unit should detect low battery condition and alert in time. Sounds like your unit does not do that. That should be built in for it to be useful.

  • TheyCallMeDave

    I went to work at an office/warehouse building the other day and saw this in the main lobby.

    They don't take good care of it... But it's sooo cool! If I worked there more often, I'd plant a few tropical in there. 3 walls are made of glass that goes up to 2nd floor and a glass ceiling. Lots of light on a sunny day and it's part of the base building (the stairs spiral up to offices on the 2nd floor with a view down)

  • Vladimir (Zone 6a Massachusetts)

    I use lithium batteries. Today, the battery operated WiFi (Ideal Sciences) system suddenly stopped operating without warning because the batteries died. This has happened many times before. I believe it is due to signal interference from my neighbor's WiFi which causes my transmitter to keep trying to transmit unsuccessfully and drains the batteries. There is no warning. It does tell you how much charge remains but you have to go to the website to find out. My wireless system calls me when the backup battery is low. Thar battery lasts about a year compared to about 1 -2 months for the Ideal Sciences system. The Ideal Sciences system allows you to download data into Excel while the hardwired does not but what does one do with that data? I don't need it.

  • isde02(zone5b)

    Katie they are 4ft x 2ft.

  • katiebeth128_wv_6b

    Tropic, no worries, I didn't feel like you were being critical at all. I like your porch set up, by the way! I'll look into those LED's a bit more. I think my next iteration of lighting will probably be based on something similar to that.

    Vlad, that's a really good thing to mention, about the battery power. Although I don't need to worry about my systems indoors because they are on a circuit with a backup generator, the greenhouse outside is not so I have to be vigilant with replacing the batteries in the sensors.

    isde02, where did you get your heating mats if you don't mind me asking? I haven't found any that big and might consider getting one for my tent

  • poncirusguy6b452xx

    Sorry all. I just do BTU load calculations and apply the heating necessary to keep my temps above 35F. I watch the weather and adjust the heat supply.


  • myermike_1micha

    Holy moly did this thread take off. Your right Katie , perfect timing fOr sure. The cold of December has already moved in. I’ve never had to start my space heaters so early. Disgusting. It seems we missed fall all together.

    I’m about to watch the football game. I’ll be back now that I feel better. Sorry for my absence Incase anyone noticed ))

    Thank god mines is up and running. i already got alerted in my email and my text !

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