Garage tropical tent ventilation question

[hemmy]

I’m looking for recommendations on venting and any other improvements for a large tropical tent in the attached unheated garage. With prolonged nighttime lows into the low 20sF, the garage has seen mid-40s. I still have a few gaps and attic access to close which may help for a Arctic blasts we might get.

Trees are mostly ficus, a bougainvillea, and some Portulacaria. I’ve been slowly improving the tropical area with more light, enclosing, heat, and fans. I believe the temperature goal is tied to the available light and growth. I don’t have a real light meter. But there are three SpiderFarmer SE3000 (LED 300W) lights. Each has a 3x3ft footprint, which I’m stretching with a 5’Wx8’Lx7’H enclosure. I still could improve the light with some type of reflective material on the walls. Given my lights, I think I can get decent growth at ~75F day (12hrs light) with low 60sF night.

But first on ventilation, I’ve had it enclosed with 4mil flame retardant plastic for a month with one end open where I blew heat in from an electric oil heater at night. Now that we are getting colder out, I’ve extended the framed tent to have an extra 2’ so the oil heater is in the tent and fans at the top circulate the air (one oscillating above the heater and another pushing air down the tent). A future step might be to seal off the heater space and use a top vent with fan to bring the air into the plant tent (a lung room). Is that better for the life of the heater (lower humidity) and less dry heat for the plants adjacent to the heater?

My current need is to add 2 vents to draw air and possibly exhaust fans to control humidity and ambient CO2. The tent with heater enclosed space is 350 cuft. The larger oscillating fan is 1300-1600 cfm and the 6” clip on fan is 190 cfm. From the online resources, a source advises replacing the volume of air every 2-3 minutes. Using an online calculator with approximate modifiers for insulation, LED lights, temperature of intake, etc, (https://www.omnihomeideas.com/patio-lawn-garden/grow-tent-room-cfm-calculator/); gives me the need for 108cfm exhaust and 92cfm intake fans to replace the air every 3 minutes. Every 3 mins seems excessive, but most smaller fans look to be in the 100cfm anyway.

Does anyone have recommendations for air replacement, fan cfm, active/passive ventilation, etc. for tropical bonsai?

Tonight, I’ll add a top 4” vent hole to the opposite end from the heat side and a 6” bottom hole near the heater. Depending on humidity levels, I’ll look to add 4-6” exhaust fan at top vent. Thoughts @cmeg1 ?

Any tips, recommendations, or criticisms are welcome.

 

[hemmy]

Since enclosing the heater 2 nights ago, night temp was 61F and then 63F, with heater set at 65F and 70F, respectively. Humidity was 70-80%. I think my goal is 60-70%. Heater is 900W on low and only runs at night, the LED lights generated enough heat in the day. But replacing air volumes, will require the heater to run more often.

Would sheet foam insulation on top of the ceiling limit enough heat loss to justify the price?

A 1.5inch R-7.5 4x8 sheet is $50 and I have scraps that could fill in the remainder. My electricity is $0.13/kWh (about 2-3x less than when we were in Cali, lol). So the heater costs $1.40/night (12hrs). I think it will depend on how much the heater runs during the day with the increased venting. I don’t want to insulate the sides, because the plastic zippers give access to the water. There is no room inside to walk. Maybe future versions have less trees or will be a built out insulated room. But on sunk cost, this one will have to last a couple years.

 

[hemmy]

Any smart heater recommendations? I was looking at this one with Bluetooth that runs 1500-700W versus another of the same brand that is 1500-900W.

Govee Smart Space Heater With Wi-Fi & Bluetooth

Model: H7130 (Black)Govee Electric Space Heater, 1500W Smart Ceramic Heater with WiFi & Bluetooth Remote App Control, Works with Alexa & Google Assistant, for Bedroom, Indoors, Office, Living Room. Smart Thermostat: Pair the heater with a compatible Govee thermo-hygrometer to enjoy a...

us.govee.com

 

[cmeg1]

Since enclosing the heater 2 nights ago, night temp was 61F and then 63F, with heater set at 65F and 70F, respectively. Humidity was 70-80%. I think my goal is 60-70%. Heater is 900W on low and only runs at night, the LED lights generated enough heat in the day. But replacing air volumes, will require the heater to run more often.

Would sheet foam insulation on top of the ceiling limit enough heat loss to justify the price?

A 1.5inch R-7.5 4x8 sheet is $50 and I have scraps that could fill in the remainder. My electricity is $0.13/kWh (about 2-3x less than when we were in Cali, lol). So the heater costs $1.40/night (12hrs). I think it will depend on how much the heater runs during the day with the increased venting. I don’t want to insulate the sides, because the plastic zippers give access to the water. There is no room inside to walk. Maybe future versions have less trees or will be a built out insulated room. But on sunk cost, this one will have to last a couple years.
View attachment 464498

Humidity no higher than 60 between 40 and 60% is ideal or they won’t transpire properly and they will overheat and get nutrient deficiencies I’ll get back to you more on this this is very interesting thanks for posting

 

[MHBonsai]

Grow Tent for Tropicals - setup guide

Setting up a grow tent can be daunting to get started. I've been pretty successful with mine for the past several years, so I thought I'd put together a quick guide on what works for me. I grow orchids, tropicals, and several 'houseplants'/kusamono successfully. I assemble it typically in...

www.bonsainut.com

There’s my system. Works well

 

[hemmy]

I’ll add a top 4” vent hole to the opposite end from the heat side and a 6” bottom hole near the heater.

Cut the holes last week and after 24hrs decided to move the 6” fan up the corner for exhaust. The humidity has averaged 57% and temp at 70F with 63-78F range. But I’ve had to keep the heat on 24hrs at 65F. Plus we had an area brownout and the heater kicked off during the day, so I might need some kind of battery backup if that were to happen while I was away. And of course, I have been researching generators. But that is a whole other post.