Polytunnel or greenhouse?

[CarolineW]

This is probably an extremely silly question, so please forgive me. I currently have a small greenhouse which I use to raise seedlings and overwinter tender plants. That's as much as I can fit in my garden. But, I'd like to put something on my allotment next year to help me to extend the season for salad, etc. People always seem to speak of polytunnels when they are looking to do that - is that because they're cheaper than greenhouses, or because they're more efficient? Also, would it have a similar effect to put up mini polytunnels over my raised beds? Or is the point that large polytunnels are warmer/have more light or something?

Sorry for my ignorance - but hoping that someone can enlighten me

Caroline

[sewer rat]

There are pro's and cons to both greenhouses (glasshouses) and polytunnels - but I will go into that tomorrow unless someone else replies before I log on - I would have replied just now but just noticed the time and I start work again in 10 mins gotta dash - sorry !!

[nick the grief]

hehehehehe, I'll jump in before Rat

Don't think of them as an instead of as Rat says they have Pro's and Cons like Greenhouses. I'm in the throws of getting one for the lottie ans yes for the same price you will get a larger Polytunnel than Greenhouse assuming you buy new can't say for 2nd hand.

I suggest that you get hold of a copy of Bernard Salts book Growing under Plastic this will tell you all you need to know.

Greenhouses are permanent where as polytunnels you have to replace the covers but most are Guaranteed for 5 years and with care you should get nearly twice this.

Plastic doesn't transmit light as well as Glass which is OK in the summer but if you want to grow this time of year it could be a problem. Condensation can be a problem as well but you can get poly covers that are treated so the water doesn't form drips.

But as it's a larger volume your tunnel will have a more stable temperature ( this assumes you spend the same amount of money and not buy a tunnel the same size as a greenhouse - if yuo see what I mean).


Rat will be able to give you more help though as he already uses them as does Piglet & JennieA

Hope this helps though.

[pigletwillie]

I have two 6x8 greenhouses lashed together on one plot and two large polytunnels on another.

If money were no object I would chose a greenhouse over a polytunel anytime but whereas my tunnels were home made for £130 (£700 bought). A similar sized glasshouse would cost nearer £10k.

Evington Hilltop Adventures: Tunnel Time 2

My tunnels are 10 x 20 and 13 x 20 and both have straight sides to 6' and an apex of 9.5'.

In real terms the tunnels are far more practical than the greenhouse due to the added height and space and the fitting of double doors each end means that excesive temperatures and humidity problems are not an issue.

As money is obviously an issue in the real world, I would not be without my tunnels. An added bonus is that they are more flexible in high winds and less likely to suffer damage provided the covers are fitted well.

[sewer rat]

Sorry about having to dash off last night !
Anyway, NtG has gone into some of the differences, as has PW.
Basically you get more a vast amount more growing space for your money with a tunnel, especially as most now come with straight sides, and the old ventilation problems have been cured by doors or louvres at each end, or by having netting on one or both sides, with mechanical rollers to raise and lower the plastic.
Tunnels heat up very quickly as do glasshouses but a glasshouse will retain more of that heat when the sun disappears - a tunnel will cool down a lot quicker.
Condensation can be a problem inside tunnels but as Nick points out there are treated covers available now that cause the condensation to run down the polythene to the tunnel base rails and not to drip onto your plants.
But what it boils down to is personal preference and finances. IMO, if you only wanna grow veggies, a tunnel is more than sufficient. If you have a hankering for exotic plants, get a glasshouse.
It is easier to grow things in baskets with a tunnel as most have optioanal crop bars, so you can grow more in what would be essentially wasted space.
If you have any more questions, let us know and we shall endeavour to point you in the right direction. I have a large commercial tunnel and have learned a lot in it's first 9 months of use, and know what I'll do different with the nest tunnel.

[xspye]

I have both poly tunnel and greenhouses and although I love my greenhouses they were more expensive to buy (although second hand one of ebay are great )and after the wind we have had recently I will have to replace most of the glass in all 3.
My plot is quite exposed so I have had lots of issues with breaking glass, so much so after this mornings inspection of last nights damage i'm seriously thinking of covering them in poly tunnel plastic and being done with it. I can't afford to keep replacing glass

[CarolineW]

Thanks, everyone. That's given me plenty of food for thought.
Caroline

[bravo2zero]

Its simple, if it very windy where you plan put alloted undercover operation get a polytunnel if not get greenhouse. greenhouses are very rigid and dont stand up to a big westerley, one rattle, a pane cracks and kabooshka bye bye greenhouse.

[poshfan]

hate to be picky - but do you mean 'throes'?