Maximum greenhouse/hoophouse temperature for cacti

Do-it-yourself projects such as greenhouse or shadehouse builds and related topics.
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jfreeman343
Posts: 12
Joined: Sun Oct 21, 2018 3:20 am

Maximum greenhouse/hoophouse temperature for cacti

Post by jfreeman343 »

Dear Members,

I have a large white Outsunny greenhouse in North Central Florida with both ends rolled and twelve side windows fully open. Worked great for Winter but now I'm seeing temperatures inside reach 99-104f even with all apertures open. New growth looks great on what is mostly 3"-4" plastic potted columnar cacti from Brazil, Caribbean and Florida. I'm concerned that it might be too hot in there, wondering what y'all think. Should I trade out the tent for 30% or 40% shade cloth clamped over the frame?

Thanks,

Jim
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Edwindwianto
Posts: 497
Joined: Tue Nov 19, 2019 12:43 am
Location: Bangkok - Thailand

Re: Maximum greenhouse/hoophouse temperature for cacti

Post by Edwindwianto »

jfreeman343 wrote: Wed Mar 18, 2020 7:50 pm Dear Members,

I have a large white Outsunny greenhouse in North Central Florida with both ends rolled and twelve side windows fully open. Worked great for Winter but now I'm seeing temperatures inside reach 99-104f even with all apertures open. New growth looks great on what is mostly 3"-4" plastic potted columnar cacti from Brazil, Caribbean and Florida. I'm concerned that it might be too hot in there, wondering what y'all think. Should I trade out the tent for 30% or 40% shade cloth clamped over the frame?

Thanks,

Jim
Show us some pictures of your greenhouse, Jim 😁
DaveW
Posts: 7074
Joined: Thu Dec 20, 2012 2:36 pm
Location: Nottingham, England/UK

Re: Maximum greenhouse/hoophouse temperature for cacti

Post by DaveW »

I presume this is what you mean?

https://www.aosom.co.uk/item/outsunny-2 ... gJqPvD_BwE

You could always try a fan similar to this on a thermostat to keep the air moving if you have electricity on site. It looks as if you do have some ventilation in it. Though vents in the roof are more effective for getting rid of hot air.

https://www.zoro.co.uk/shop/power-tools ... gI7avD_BwE

A nurseryman I knew in the UK had a polytunnel type with only vents in each end and it formed condensation inside and his plants were getting mildew therefore the answer is to keep the air moving.

I have had temperatures over 100F in my glass greenhouse in summer, but it is polythene lined for winter and left up in the summer and the plants have been OK. Unlined clear glass may burn them at those temperatures though, but your plastic greenhouse should filter the sun.
jfreeman343
Posts: 12
Joined: Sun Oct 21, 2018 3:20 am

Re: Maximum greenhouse/hoophouse temperature for cacti

Post by jfreeman343 »

Thanks, Dave.
That sets my mind at ease. Since I cut the back doorway on this thing a few days ago to function more like a grow tunnel, the temperatures have been maxing out at about 96f when it is 89-91f outside for this abnormally hot start to Spring. I put the thermometer in a shadier spot. The greenhouse came with what looks like 30% white shade cloth adhered to the polyethylene. I'll mount a double draw fan inside one end but out of rain's way when it gets hotter and more humid.
Best,
Jim
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