This is probably very obvious but.......

[gardening_gal]

Why are most tunnels round and most fruit cages are square?

Tomato or cucumber plants can get as tall as fruit bushes so it can't just be for height reasons?

(Cut me some slack, my grey cells don't re-populate as they once did )

Please feel free to add any 'obvious' questions you may have to the thread.

(Really, please do )

[nickdub]

probably tunnels are roughly semicircular in x-section because that way there's no edge-type pressure point on the plastic cover, which is the weakest part of the construction - netting doesn't have the same forces applied to it as the wind mostly goes through it, so you can make the sides up-right which provides more usable growing space.

Not sure if any test have been done on the exact x-section of poly-tunnels and how they perform in strong winds etc.

[Thelma Sanders]

I should think that the tunnel's rounded top allows wind to sweep over the it, - rather than hit them with full force n their sides, and for rain to run off ? Greenhouses have low sides and then a slanted roof for the same reasons, I imagine.

Netting over fruit cages is to stop birds from getting in rather than to stop wind/rain getting in - so no need to be curved/slanted.

Nick beat me to it - I think he's saying the same thing but in more technical language lol

[gardening_gal]

I knew there was an obvious reason.

Thank you both.

[veggiechicken]

A flat roof would puddle when it rained, unless there was a slope or drainage.The poly would sag and stretch under the weight of water.
Its not a problem with netting.

[bikermike]

cheapest way of making them - see also Nissen huts.


No corners/joints to fabricate, make waterproof

[rary]

I always thought that they are that shope so that poly can be pulled tighter over hoops, no edges, and wire can be pulled tighter over a flat areax