Time for a tunnel

Hi all
Looking for a tunnel, probably one of the 'blow away' types 15ft x 10ft would be good. Can't really afford an real tunnel. With the right prep and secured properly are they worth it?? Looking at this one on ebay from crocodile trading 4m x 3.5m allotment master extreme polytunnel

or can anyone recommend a tunnel

Can you get spare covers or proper clear polythene as seen on the more expensive tunnels?

 

Tried to post a link but it would not let me.

 

00000000000000000000000000001348I have a 6m x 3m (20ft x 10ft) on my allotment. It cost £100, delivered, from Tesco online.

 

Hi Rob,
Go for it!.... I bought a 6mx3m with 32mm galvanised tubing with 2x metal doors and am well pleased. I've anchored it down with 6x2.4m poles each hammered 1m deep so it ain't going nowhere in a blow!
Checkout the 'stickies' up top to give you some ideas.
Ready made covers and polytunnel plastic can be bought online.
Have a nice day John

 

Hi Rob,

They will give you a few years use, it all depends really on how exposed your site is and therefore how protected your tunnel will be.

http://gardenerscorner.co.uk/forum/threads/steves-polytunnels.33033/ My polytunnel topic here in this section shows how I put together and anchored 3 different "blowaway" tunnels and my 4th much more substantial tunnel put up this year.

It goes some way to show the evolution of these cheaper tunnels, starting with the white powder coated frame, 4 hoop, 1 ridge, version, these will last 4 years or so, rust kills it and wind finished it off.

The next was an all galvanised steel 7 hoop, 2 ridge, 4 corner brace. This frame will rust but it is only surface rust.

The third is much the same but with 3 ridge poles, so much stronger. I've mounted that frame on top of scaffold boards for extra height.

My fourth is much more substantial in that it is an ex commercial frame with real polytunnel plastic on it, total cost was twice the cost of one "blowaway".

Blowaways: The height can be a little restrictive, most are 6ft at best and that is down the very centre of the tunnel. So if you opt for a central path, the bed either side of it will be around 5ft max height to around 3.5ft on the outer edges. Workable and usable, look for @Scrungee polytunnel topic to see how he uses his.

The opening side vents whilst useful in the first year, will degrade over time and start to tear in the second and third.

Zipped doors are also useless as they jam very easily, its best to make and fit your own timber framed doors which also adds to the overall strength of the finished tunnel too.

Covers: Although they are reinforced checker board covers, they too can fail. My second blowaway suffered when the little bits of plastic between the reinforcing mesh, all fell out. End result was a polytunnel teabag. Seams are also a longer term issue in that 4 or 5 years in the stitching rots away and the wind will open it up. I stitched one end back together using garden wire by poking it through the reinforced mesh and using a running stitch managed to pull it back together for another season.

Not supplied with your tunnel (or any blowaway) is anti hotspot tape, this is applied to your frame before fitting the cover. The frame heats up and if in contact with the cover, degrades it much quicker. The tape is a barrier between frame and cover.

When my 2nd tunnel changed to a teabag, I priced up the cost of a straight new cover or the cost of covering the same with proper polytunnel plastic, at that time a 10ft x 20ft tunnel in polytunnel plastic worked out at just under £100 and a replacement cover was around £70.

For more info and photos to show what the words describe, see here http://gardenerscorner.co.uk/forum/threads/steves-polytunnels.33033/

Steve...

 

@Rob Taylor Whatever cover you go with, consider replacing all the bolts supplied with longer ones from Wilkos. These are relatively inexpensive if crammed into one of their 'pick and mix' bags and bought for a few pounds. Their lower profile heads fit better under anti-hotspot tape and they enable continuous timber battens to be fixed along all the horizontal tubes, plus all sort of fittings to be connected at bolted tube intersections. For example:

Top strut fixing (and top timber batten) and canes fixed to eyes screwed into batten (more eyes on another batten at ridge level enable further canes to be added above).




Lower battens, these have been located top and bottom of the mesh panels to make repair/like for like replacement easier, and the top rail (fixed with saddle clips) is to take the back edge of demountable staging. I use those lower eyes to attach strings to the middle of rear canes and pull them into a bend so they're parallel with the cover and reduce congestion in the middle of the borders.



The (extended) bolts for the very bottom rail also hold an edging board in place plus L shaped metal straps cast into concrete pad foundations that (together with those struts) hold the tunnel down rock solid.



A little bit of thought prior to installation can make a tunnel a lot more versatile.

 

stainless bolts would be best but could cost you more than the tunnel. If you coat zinc bolts/hardware with a thin layer of vaseline it`ll keep the moisture off and they wont rust as fast.