Ventilation for large PT?

adri123 · « **on:** October 14, 2013, 17:55 »

Hi,

Still fitting out our new 14x54 PT. I know that a big issue is going to be ventilation. We have double doors at either end so they can be opened.

What i'd like is some sort of system (possibly extraction) which could kick in automatically if for eg I can't make it to the PT to open the doors one day. Perhaps solar panel powering a fan? Thing is with such a big tunnel it's going to need a BIG fan...

Any ideas?

TIA.

Adri.

3 allotments · « **Reply #1 on:** October 14, 2013, 19:03 »

hi adri I have a 20ftx10 pt with zip either end so I built a door frame with door at one end and put a 2ftx2ft old house window in above door, window is on hinges so I bought 2 autovent window openers about,�18.00 each from amazon, fitted them on,they work perfectly with the heat inside not had to open door at all [keeps the cats out]

.Hope this is of some use to you, good luck

.darren

jrko · « **Reply #2 on:** October 15, 2013, 10:17 »

I've seen some with replaceable side panels that zip out between support hoops. Only issue would be ground frost ingress?

It wouldn't be too hard (or costly) to replace the top panels of your doors with 4mm twin wall polycarbonate, hinged at the top with either an opener or just an adjustable windows latch

If you want powerful fans, car radiator fans are 12v and you can get brand new 12"ers for about �20 and they are suitable for hostile enviroments. If you made one of the opening frames as described above and inserted 1 of the fans in the gap at the bottom, facing downwards, filled in the sides etc and had a couple of decent solar panels and a battery or 2, it will shift up to 660 cubic feet per min without mains connection

A simple 12v thermostat can kick it in at a set temp and hey presto!

3759allen · « **Reply #3 on:** October 15, 2013, 22:31 »

this is my first year with a 14 x 30 tunnel. during the summer i just left both doors open day and night (as long as there's no forecast temp below 10 degrees. next year i will put a fine net in replacement of the doors to keep pests out.

i have vents roughly 1 x 2 built into the top of both doors and just open them in the morning and close at night over winter. times aren't really to important in my opinion, guess it depends what your growing and what time of year.

i would always be paranoid that the automatic vents may not open, and have to check them everyday anyway. so may as well just open and close manually.

i think it's better to be a bit colder than too hot and humid. one day i underestimated the the temperature and everything was looking very sorry for it's self.

Kristen · « **Reply #4 on:** October 16, 2013, 07:51 »

Quote from: 3759allen on October 15, 2013, 22:31

next year i will put a fine net in replacement of the doors to keep pests out.

I wonder how fine a net is required? Need to keep birds and rodents out, but allow pollinating insects in? perhaps beneficial insects too?

3759allen · « **Reply #5 on:** October 28, 2013, 15:46 »

Quote from: Kristen on October 16, 2013, 07:51

Quote from: 3759allen on October 15, 2013, 22:31
next year i will put a fine net in replacement of the doors to keep pests out.

I wonder how fine a net is required? Need to keep birds and rodents out, but allow pollinating insects in? perhaps beneficial insects too?

the main problem i had was butterflies, surprisingly non or very little problems from other pests. so i will use a fine net over the doors and remove before and after the peak times of butterfly activity. if need be i will hand pollinate if insects can't get in.

if i do have other large pests i would prob use debris netting until the butterflies emerge, thinking about it prob make velcro net doors with a weighted bottom so the size of net can changed when needed.

Eblana · « **Reply #6 on:** October 28, 2013, 17:43 »

I use debris netting in my 14 x 25 PT doors during the summer. It helps keep it ventilated. When I am up at the plot I leave the doors open and pollinators get in then.

adri123 · « **Reply #7 on:** October 28, 2013, 19:53 »

A bit over zealous on the moving topics!!

The topic is about ventilating a Polytunnel...seems related to growing in a polytunnel to me...

jrko · « **Reply #8 on:** October 28, 2013, 20:34 »

Quote from: adri123 on October 28, 2013, 19:53

The topic is about ventilating a Polytunnel...

Purely a technical question so belongs here.

Growing issues are in the...um...growing section

Debbieta · « **Reply #9 on:** November 15, 2013, 20:25 »

Hi I'm fairly new to this site, been on chicken one's often enough, but now a whole new world.
We have gained a polytunnel at our school, but I am 'in charge' but only work there 3 days a week.
What I am hoping to do next spring/summer is use a fine green mesh on the days that I'm not there, pegged to the door frames to stop the local cats and cabbage white butterflies (that were around a lot this year) from getting in. Then use a larger holed net on the days that I am there to let the beneficial insects in but still keep the 'unwanted' out. But I have to say this is a huge learning curve !!!!

mumofstig · « **Reply #10 on:** November 15, 2013, 21:52 »

Which veg will be you growing in the tunnel?
It's not really a good idea to grow brassicas in a polytunnel in the summer anyway

Greenhouse Ventilation Started by pipfit on Equipment Shed	2 Replies 1511 Views	January 17, 2010, 09:17 by Bigbadfrankie
Large plot rotovator Started by thatruddyvicar on Equipment Shed	2 Replies 1745 Views	September 26, 2012, 21:58 by Bigbadfrankie
Large lace cloche. Started by Kleftiwallah on Equipment Shed	3 Replies 929 Views	May 09, 2019, 10:16 by Aunt Sally
Best tools for digging up and repositioning large shrubs Started by Emma Fletcher on Equipment Shed	4 Replies 1773 Views	August 10, 2020, 11:18 by jezza

Ventilation for large PT?

adri123

Ventilation for large PT?

3 allotments

Re: Ventilation for large PT?

jrko

Re: Ventilation for large PT?

3759allen

Re: Ventilation for large PT?

Kristen

Re: Ventilation for large PT?

3759allen

Re: Ventilation for large PT?

Eblana

Re: Ventilation for large PT?

adri123

Re: Ventilation for large PT?

jrko

Re: Ventilation for large PT?

Debbieta

Re: Ventilation for large PT?

mumofstig

Re: Ventilation for large PT?

Similar Topics

Greenhouse Ventilation

Large plot rotovator

Large lace cloche.

Best tools for digging up and repositioning large shrubs