Steve's Polytunnels

Planting outside was always the plan Marley, but I wont need to go to the trouble of growing it through a pipe as I am not trenching this tunnel in, my polythene will be attached to base rails so I will only have to untighten a few bolts and the whole side of the tunnel (poly)will lift.

I am still considering a side rail and base rail combo which would give me more options such as fitting some vents, fitting a mesh screen or netting or just lifting the side a few inches for ventilation.

Steve...

 

Fantastic idea Steve and bargain too

I do have one thought though, apologies if you have already mentioned this, if you are using the tunnel as a brassica area, aren't you worried about pest/disease build up in the soil over time?

It would make a great fruit cage

 

This new (to me) tunnel is 18 x 30 x 9 feet and will be used as proper polytunnel, one of my two smaller ones 10 x 20 x 6 feet will be converted into the walk in brassica frame and it will be moved every season as per normal crop rotation.

I already have two fruit cages, and this winter they are both being moved and merged into one, so lots to do..

Steve...

 

Ahhh OK

You have a right set up Steve!

 

Progress:



I've started work preparing the area for my new much larger and stronger Polytunnel.

In the photo above you can see my 2 x 20ft x 10ft tunnels, one without a cover on, I have sold this tunnel to another plot holder, the new tunnel covers that area and over to the right to include the smallish bed with the white land drain tube resting atop it and as far forward as the ground in front has been rough dug over (Right up to the pallets).

Normally with something like this I would just get on and get it done, and let everything else needed to be done...wait! But this time around I am being sensible and ensuring all other work is done, then working on the new addition. Hopefully it will get finished in a couple of weeks as work, weather and time allow.

Steve...

 

Over the last few days I have started work on my new polytunnel, starting with foundation tubes for the hoops. Each foundation tube is 32 in long and has a base plate attached at it base, deep under the soil to stop it from sinking or lifting.

The base plate is placed at the bottom of the dug out hole and the foundation tube is driven in a little, using a fence post spirit level to keep it square and true.



Now remove the base plate and fix an exhaust clamp to the tube.



Slide the base plate back over the tube, followed by another exhaust clamp. The base plate is now fixed in place on the tube by the two clamps.



Back fill the hole and consolidate the ground as you do so.



Next I made up the two tunnel end frames. The tunnel is 18ft wide so I have made the frames 6ft wide using 4 x 3 timber, it will sit central in the end hoop and later double doors will be fitted in there.





Next the hoops where assembled, placed onto the foundation tubes and bolted on, a ridge bar was attached using bolts and "P" clips to join the hoops together. And the end frames where dug into the ground and attached to the hoop, I straightened out a "Q" clip, fixed it to the front of the end frame then hammered it round and over the top of the hoop and bolted it to the back of the end frame and to the hoop itself.









Taking a few days off from building this now to catch up on some other plot jobs. I'll hopefully get this finished off later this week.

Steve...

 

I got the side and base rails fitted yesterday, these add extra rigidity to the overall structure and they are also a fitting point for the plastic cover. Using these helps you get that "drum" like tension in the cover that stops it flapping about in the wind and so prolongs it's life, but more of that later.



Corner clamps





Side clamps







Less wind tomorrow so the cover goes on Friday morning.

Steve...

 

A day was spent firstly applying "anti hotspot tape" to the hoops then to any other areas with sharp corners and or edges (Timber corners of the side rails etc). Anti hotspot tape is an adhesive backed cushioned tape roughly 5mm thick with a glossy back. Metal hoops heat up in sunshine and direct contact with the polythene cover can quickly degrade it, so applying the tape protects against this heat transfew and allows for easier covering of the frame as the cover slips over effortlessy.

We pulled the cover over on Friday morning and into position, using timber battens it was fixed at one end to the door frame lintel then with a couple of friends pulling like mad I secured the other end in the same way.

Next it was stapled to the side rail on one side, which was then capped with yet more timber battens screwed through the ploythene cover into the side rail. The other side was done next in the same fashion whilst the cover was pulled over and down to get some tension into the cover.

Again pulling the cover it was stapled to the base rails on both sides

Next the ends where done and you have to accept you are going to get pleats in it, starting from the top of the door frame edges the cover is pulled over it and it is stapled in place, 6 inches at a time, then pull the next portion of cover and staple. When we got down the door frame edge to the side rail we switched to the side rail area at the corner of the tunnel (but still working the cover at the end of the tunnel) and repeated the process, six inches at a time working back along the side rail towards the door frame. When that was completed we timber battened over the top of the door frame edge and end side rail, rinse and repeat for the other side of the door, then the other end. Then tension the plastic between the side and base rails on both ends and finally cut away the excess plastic and cut out the door area leaving 12 - 15 inches or cover so you can tidy that area back around and inside the tunnel behind the door frame and secure.

I still have work to do on this but it is now mostly done, I'll update this topic when I have made and fitted doors and then when I finally tension the cover.


Timber batten covering the polythene cover onto the side rail


Battened and finished side rail, stapled base rail.


Completed end.excess polythene cut away.


Comparison, older 10ft x 20ft tunnel on the left



Steve...

 

Well it was quite late in the season last year that I completed the basic shell of the tunnel so time was against me to do much more. I planted a giant pumpkin in there which went completely bonkers.

This year I have rotovated it, laid a pathway and constructed beds. The beds are 4ft wide at the pathway end and are separated by 1ft x 4.5ft access pathways, at the tunnel sides the beds are 3ft wide. At one end of the tunnel I sacrificed one bed and paved that area too, I will make a potting bench for there and stand tools, watering cans etc.


Plants top left are just some "heeled in" fruit bushes, they will be going outside very soon.


The angled cane next to the frame is my new grape vine it's a 2 year old plant and the buds are just about to break. This area naturally stays moist so watering will not be an issue.



View from the back of the tunnel, paved work area far left.

Still much to do but that is for another day/week/month.

Steve...

 

Lookin good and ready to go Steve

 

Looks like a very efficient area of beds:paths ratio, and scaffold boards could always be laid across the keyhole path edgings to make access to rear areas easier.