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Post by belugaleuca on Mar 3, 2022 12:40:59 GMT -5
So this is my first post in months... Ever since moving to my new apartment, my aerogarden had been plagued by high temperatures, algae and bolting lettuce. Once I added ice cubes to cool the water, but the plants only got shocked and stopped growing. I got so discouraged I took a break from the aerogarden for a bit. Prior to stopping, I had thought that maybe the water pump was contributing to high temperatures, and so I unplugged the water pump and put an airstone there instead. I threw in a temperature sensor and recorded the temperatures for a while. Unfortunately, there was no appreciable difference in temperature and I threw in the towel! Just over a month ago I thought I'd give it a go again. I took apart the harvest and sanitized all the parts, and started again fresh. Once when I was changing the water, I felt the base of the Harvest and it was HOT. Like, cooking hot. Aha, I thought this is where the heat was coming from. So I took the reservoir off the base so that the heat would no longer transfer so easily to the water. I again threw in the temperature sensor and logged a couple temperatures on a piece of paper on my refrigerator now and then. The great news is that the temperatures are staying in a better range and my lettuce is not bolting! That makes me so happy. Methodology drawbacks: Since the previous temperatures with the reservoir on the base were taken in late August - September 2021, and the temperatures with reservoir off the base were taken in late Feb - March 2022, It's possible that ambient temperature contributed to the difference. However, I think that our house temperature is relatively stable so probably not. Also, you can see that the baseline lowest temperatures is the same for each set (around 21 degrees) and that is because the tap water is always the same temperature when I refresh the tank. The difference between the water temperatures was 2 degrees C on average. Max temperature before moving the reservoir was 28 C, which is way too high! And after moving the reservoir the max is 24.5 C. That's a major improvement in my opinion and is the difference between a viable lettuce plant and something that bolts and tastes bitter.  See the charts below of the difference in temperature:  Boxplot of temperature:  |
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Post by belugaleuca on Mar 3, 2022 12:50:07 GMT -5
I also was thinking - the reason why I didn't have this problem until moving to the new apartment is because in the old place, I had the aerogarden sitting directly on a cold floor. I think that maybe the cold floor helped cool down the base of the Aerogarden and so the water stayed cool.
It doesn't look the neatest when the base is all offset like this, but it works for now. I wonder if Aerogarden engineers are aware of this design problem (with hot electronics contributing to overheating reservoir)!
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airscapes
AGA Bounty
Lettuce eat Cake!
Posts: 642
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Post by airscapes on Mar 3, 2022 13:30:45 GMT -5
The 2 largest contributors to heating the water in all of my DIY units are the lights and the pump. Running pumps 24x7 can raise water temp by 5 degrees (at least in mine). So setting your pump to what is really needed by the plant and not on constantly running it will help in keeping the temp down. One would assume that more is better but when the root system is mature in in the water the pump is not really doing much but helping circulate the fertilizer and helps to oxygenate the water as it drips through the air from each of the nozzles. Setting to on 3 off 25 should be fine for most plants, my tomato is doing fine with it set like that and both of the larger unit run 15 minutes every hour. This keeps all water temps around 69F if run constantly can climb to 74+ Temp is taken at 8am so before lights have been on all day.. Should probably check it at 9pm to see how much the internal air temp raises the water temp.
I also cover the tops of my units with 1/2 or thicker foam insulation (probably not all that attractive on an actual aerogarden unit)
You may want to consider cutting a piece of foam insulation (white Styrofoam or the pink/blue foam board sold for contruction) 1/2 would be fine to fit in the base and then the resivoure could sit normally on top of the foam with the same or better results vs turning it sideways. A nicely cut piece on top would probably do a world of good as well.
Good luck!
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Post by belugaleuca on Mar 3, 2022 13:57:06 GMT -5
Thanks!! Styrofoam is a great idea. I was thinking and thinking what would be easy to use to also stop the light from heating the deck, because it does get warm to the touch, but I never settled on anything.
As for the pump schedule, I just checked and my Harvest (Elite) doesn't have any settings for pump timing. It just has a function called "Test Pump" and it runs the pump for a bit. But that's it.
I did note that the pump occasionally feels warm if I feel it, and that's why I switched to an airstone last August. But the "Reservoir on base" temperature data in my graphs actually are taken when the pump was off and I was exclusively using an airstone, so I figure there must be major heat contributors other than the pump as well.
So we've identified three heat sources: Pump, Light hitting the deck, and Electronics in the base.
I'd expect that maybe in the larger units, the heat from electronics in the base is not as big of an issue since the tank is so much larger compared to the control system, though.
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Post by belugaleuca on Mar 3, 2022 14:15:12 GMT -5
According to the Aerogarden Harvest Elite data sheet: "Your Pump cycle is set to be ON for 5 minutes and OFF for 25 minutes." That's pretty close enough to your suggestion of on 3 and off 25 I think. I'd really like to do a more elaborate temperature comparison (maybe with no plants) after this crop: - Default setup - Pump vs airstone - Reservoir on the base vs off the base - Styrofoam on the deck - All three strategies combined For maybe 3 days each and make another boxplot |
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airscapes
AGA Bounty
Lettuce eat Cake!
Posts: 642
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Post by airscapes on Mar 3, 2022 14:42:27 GMT -5
From all you have done, I am guessing you have a lot of heat from the electronic in the base and from the light.. that pump setting i is what I meant.. the 3 was a fat finger :-) Just looked at my spread sheet and it is obvious where I turned the pump on constant (do that when checking levels) and forgot to turn it off till next day.. temp was up 4+ degrees.
Before I got the foam cut for my 3 systems. The water was in the mid 70s, but was in the germination stage so was not an issue. interestingly, the one unit that is built from 1/4" vinyl trim board was several degrees cooler than the bus tub and 5 gallon buckets that are just made of thin material. Now all 3 units are within 1/2 degree of each other with the foam and similar pump times. Note buckets hold 8 gallons, tub holds 4 and DIY bounty 2 gallons (1/4 in vinyl) all stay about the same with the tops insulated from the lights with foam.
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Post by lynnee on Mar 3, 2022 16:12:05 GMT -5
I also was thinking - the reason why I didn't have this problem until moving to the new apartment is because in the old place, I had the aerogarden sitting directly on a cold floor. I think that maybe the cold floor helped cool down the base of the Aerogarden and so the water stayed cool. It doesn't look the neatest when the base is all offset like this, but it works for now. I wonder if Aerogarden engineers are aware of this design problem (with hot electronics contributing to overheating reservoir)! Thanks so much for reporting all of your research, and for posting the photo of how you lifted the bowl off the base! I'm going to try that for my gardens in the upstairs room that gets so hot in the afternoons. It really surprises me that the AG base gets "cooking hot". Could it be that you actually have a defective unit? I'm going to go check all of my AGs this afternoon to see whether any the bases are getting hot. Certainly this is one more thing for people to check when they're doing everything by the book and their plants still aren't growing well!  |
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Post by lynnee on Mar 3, 2022 16:21:00 GMT -5
The 2 largest contributors to heating the water in all of my DIY units are the lights and the pump. Running pumps 24x7 can raise water temp by 5 degrees (at least in mine). So setting your pump to what is really needed by the plant and not on constantly running it will help in keeping the temp down. One would assume that more is better but when the root system is mature in in the water the pump is not really doing much but helping circulate the fertilizer and helps to oxygenate the water as it drips through the air from each of the nozzles. Setting to on 3 off 25 should be fine for most plants, my tomato is doing fine with it set like that and both of the larger unit run 15 minutes every hour. This keeps all water temps around 69F if run constantly can climb to 74+ Temp is taken at 8am so before lights have been on all day.. Should probably check it at 9pm to see how much the internal air temp raises the water temp. I also cover the tops of my units with 1/2 or thicker foam insulation (probably not all that attractive on an actual aerogarden unit) You may want to consider cutting a piece of foam insulation (white Styrofoam or the pink/blue foam board sold for contruction) 1/2 would be fine to fit in the base and then the resivoure could sit normally on top of the foam with the same or better results vs turning it sideways. A nicely cut piece on top would probably do a world of good as well. Good luck! That is great advice about running the pumps less, and about pump settings that should work, airscapes! I've been wondering how to manage the room temp for my AGs this summer, when it's already going to 78-80 degrees F. in February. Do you put the foam board on top of the light hood? Could you post a photo or link for the stuff you use? I'm always worried about setting our place on fire--usually quite baselessly.  |
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Post by lynnee on Mar 3, 2022 16:29:35 GMT -5
belugaleuca, if you do another temperature comparison, I hope that you'll post the results! You and airscapes have given me a lot of ideas for handling room temperatures this summer. 
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campingcorgis
AGA Farmer
🌴 I wet my plants. :-) 🌴
Posts: 3,114
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Post by campingcorgis on Mar 3, 2022 17:55:23 GMT -5
I also was thinking - the reason why I didn't have this problem until moving to the new apartment is because in the old place, I had the aerogarden sitting directly on a cold floor. I think that maybe the cold floor helped cool down the base of the Aerogarden and so the water stayed cool. It doesn't look the neatest when the base is all offset like this, but it works for now. I wonder if Aerogarden engineers are aware of this design problem (with hot electronics contributing to overheating reservoir)! I would like to gently suggest contacting the AG folks. I just ran around and checked all of the bases on my Harvest and Bounty machines and they are about room temperature to touch. No heat whatsoever. I worry that your until may be faulty...  |
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Post by lynnee on Mar 3, 2022 23:42:35 GMT -5
None of my AG Bounty Elite bases (5) are warm to the touch, either! The Farm hoods get a little warm when the lights are on (some a little more than others), but they aren't hot. All of the LED light hoods get hot, but not in a worrisome way.  |
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Post by belugaleuca on Mar 4, 2022 0:01:50 GMT -5
From all you have done, I am guessing you have a lot of heat from the electronic in the base and from the light.. that pump setting i is what I meant.. the 3 was a fat finger :-) Just looked at my spread sheet and it is obvious where I turned the pump on constant (do that when checking levels) and forgot to turn it off till next day.. temp was up 4+ degrees. Before I got the foam cut for my 3 systems. The water was in the mid 70s, but was in the germination stage so was not an issue. interestingly, the one unit that is built from 1/4" vinyl trim board was several degrees cooler than the bus tub and 5 gallon buckets that are just made of thin material. Now all 3 units are within 1/2 degree of each other with the foam and similar pump times. Note buckets hold 8 gallons, tub holds 4 and DIY bounty 2 gallons (1/4 in vinyl) all stay about the same with the tops insulated from the lights with foam. Thanks for sharing all of those details! It's great learning about what you've tried and how you've managed to keep the temperature steady. I'm just looking around now for a piece of styrofoam or similar to try this out. It's also really valuable to know that having the pump on constantly will have such a dramatic effect. 4+ degrees is sure a lot. |
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Post by belugaleuca on Mar 4, 2022 0:06:34 GMT -5
Thank you lynnee and campingcorgis for checking your units and sharing! I'm concerned now that maybe my unit really is defective  . I'm not sure if Aerogarden can do anything for me since my unit is well past its warranty, but it doesn't hurt to reach out and see what they say. In the meantime I guess this little workaround of moving the reservoir will have to do. |
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Post by belugaleuca on Mar 24, 2022 11:37:49 GMT -5
A number of updates: I reached out to Aerogarden and showed them my graphs, and their team suggested my unit was defective and they kindly sent me a new unit. They also asked me to ship the old unit back to them, and the packing slip is good for a month. That means I have a short period of time to test the units side by side to confirm what is happening. While waiting for the new aerogarden I still had lingering doubts as to whether it really is defective or if this is a design issue. I would hate to charge the company for a new one if it wasn’t defective after all! So in the meantime I really wanted to confirm whether air temperature did or did not account for the differences I had measured (since the temperatures “on the base”were recorded late summer and the temperatures “off the base” were collected early this year) so I collected more data with the Aerogarden on and off the base. The result is, the outside air temperature does correlate with the Aerogarden water temperatures, but removing the reservoir from the base still made about a 2 degree C difference. A second question came up as I thought about airscapes experience: Could it be possible that shifting the reservoir simply reduces the amount of light hitting the top, and therefore reduces the heat by receiving less light? Here are the new graphs with more data: Yellow = On the base Blue = Off the base  Noticing that temperature stabilizes after around 12pm each day, here is a second plot comparing the outside air temperature (collected from vs. Aerogaden water temperature with only the data collected after 12pm:  And so it is that the weather does affect the Aerogarden, but for a given air temperature, keeping the reservoir on the base still makes it about 2 degrees warmer. |
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Post by belugaleuca on Mar 24, 2022 12:07:19 GMT -5
With two Aerogaden Harvests for a short time, it is now time to do the side by side testing. I put together a temperature logger I’d been planning to make for a long time. There are 2 waterproof temperature sensors and an air temperature sensor, logging the temperatures and timestamp to an SD card. Parts: - Arduino Uno - LM35 analog temperature sensor (for air T) - 2x DS18B20 digital temperature sensors (for water T) and a 4.7 kOhm pullup resistor for the digital signal line - DS3231 real-time clock for keeping the time - adafruit mini SD breakout for logging data. Theres a battery in the picture, but that is replaced with a usb 5V wall charger because I read that Arduino Uno will deplete a fresh 9V battery within 1 day!  Here is the circuit though it is not soldered or tidy, since this is a temporary experiment I may or may not take it apart when it is done. The good news is that all of the sensors are measuring within ~0.5 C of each other. As for the side-by-side AG test, here is the first setup:  Here is the plan so far: * for each day, start with a fresh water refill at the same time. Day 1 (today) - Refill both tanks and log water temperature with the Aerogardens unplugged. This will tell us how water temperature correlates with Air temperature with no heat inputs. Day 2 - Plug in Aerogardens with no light on, and pumps unplugged. Day 3 - Plug in the pumps and keep the lights off. This should indicate the pump contribution to heat. Day 4 - Turn on lights at the same schedule for both gardens. Day 5 - Offset the aerogardens from the base like before. Day 6 - Put the Aerogardens on the base again but cover the top with styrofoam or other insulator. Day 7 - Put a spacer between the base of the unit and the reservoir (i.e., offset + insulator) and thats all I can think of to cram in before I might have to send one Aerogarden back, if indeed it is defective. |
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airscapes
AGA Bounty
Lettuce eat Cake!
Posts: 642
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Post by airscapes on Mar 24, 2022 14:19:03 GMT -5
Nice job on the monitoring rig! I look forward to your finding!
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Post by lynnee on Mar 24, 2022 14:34:27 GMT -5
I wish that I had the programming and circuitry expertise that you two ( airscapes, belugaleuca) have! I always enjoy reading about your experiments.  |
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Post by belugaleuca on Mar 26, 2022 1:55:20 GMT -5
I wish that I had the programming and circuitry expertise that you two ( airscapes , belugaleuca ) have! I always enjoy reading about your experiments.  It's never too late to learn! Really I am also a beginner in circuitry, making mistakes all the time . Never thought I'd be interested in it when I was young but some years back my family gave me an Arduino kit and those things make circuits really accessible and fun for new learners. |
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Post by belugaleuca on Mar 26, 2022 2:15:46 GMT -5
Day 1 - Both Aerogarden Harvests are Unplugged: - Fresh tap water added to the reservoirs at 8:00 am  Note 1: I made a mistake in the code, resulting in low resolution data for the air temperature. It should still be accurate, though. Next time hopefully it will be better. Note 2: It seems like the water temperature is stabilizing cooler than air temperature, and this surprised me, but it turns out that's actually normal! Found a discussion on this on physics forums: www.physicsforums.com/threads/why-is-the-temperature-of-water-low-than-atmosphere.595097/Apparently it has something to do with evaporative cooling - when the water is evaporating it makes the water body a little cooler. As long as the air is dry enough, this process will continue, keeping the water cooler than air. I'll keep logging overnight to see if it stays cooler than air all night. |
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Post by lynnee on Mar 26, 2022 10:14:33 GMT -5
I wish that I had the programming and circuitry expertise that you two ( airscapes , belugaleuca ) have! I always enjoy reading about your experiments. It's never too late to learn! Really I am also a beginner in circuitry, making mistakes all the time . Never thought I'd be interested in it when I was young but some years back my family gave me an Arduino kit and those things make circuits really accessible and fun for new learners. You're right--I've got to make time to learn Arduino. I have the kit and some books already. You are supplying the motivation! |
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. I'm not sure if Aerogarden can do anything for me since my unit is well past its warranty, but it doesn't hurt to reach out and see what they say. In the meantime I guess this little workaround of moving the reservoir will have to do.
