Maths and formulas are not my strong point

[bussinspain]

Can any one help me please?
I need to know what length of alkathene pipe (tough plastic water piping) to buy to make hoops for tunnels for my veggie garden. They will be 1.75m wide by 4m long in total and about 2 m high (so that I can stand up and work under them - I am 5' 6")

I plan on putting metal pipes in the ground so that 1m is below ground and 1 m above ground. Then to put the water pipe over the protruding metal pipes.

How do I work out the total length of plastic pipe (from the ground, up and over and down the other side) please?

Does any of that lot make sense?

I have some frames covered in a fine green netting and the veggies are protected from the scorching sun and from bugs - veggies are so much better under these, so I want to cover all 4 of my beds in this way.

Thanks

[KevinM67]

1/2 Pi d ??

Although this may help


https://youtu.be/-z4SUypJZxo

[WendyC]

I'm imagining a semi circle 1.75 m wide with two 1m long legs. So semi circle will be 1.75 x 3.14 divide by 2= 2.75m. Add the two legs is 4.75m each. How stable they would be at that height/ length I'm not sure.

[veggiechicken]

If your metal posts are 2m (taller than you are) have you thought about how you're going to whack them into the ground?

[Thelma Sanders]

You need 2.75m for the round top part of the hoop plus the height of the 2 straight sides.

so 2.75m +2m +2m = 6.75apx per hoop.

1 hoop at each end and a middle one should do it 20m should do it.

Need someone to check the calculations though

[goodolpete]

Can any one help me please?
I need to know what length of alkathene pipe (tough plastic water piping) to buy to make hoops for tunnels for my veggie garden. They will be 1.75m wide by 4m long in total and about 2 m high (so that I can stand up and work under them - I am 5' 6")


How do I work out the total length of plastic pipe (from the ground, up and over and down the other side) please?

Does any of that lot make sense?

I have some frames covered in a fine green netting and the veggies are protected from the scorching sun and from bugs - veggies are so much better under these, so I want to cover all 4 of my beds in this way.

Thanks

Hi,
the arc at the top will be half a circle of approx 0.9m (half of 1.7m rounded up). Half the diameter
of a 0.9m circle is half of 2 times pi (22 over 7) times radius (0.9), which is near enough 3m.
If you then had vertical sides of one metre each side, your tunnel height would be 1.9m.
This means every complete loop is 5 m long.

[KevinM67]

So to add - if they were 'perfect' semi-circles from ground level, then each length of piping would be 2,745.5 mm.

However, with the metal piping and the increased height then there is obviously room to play about with.
Additionally, the no. of lengths of piping for a 4m polytunnel could be up for debate.

[KevinM67]

Oops - I had to call in the middle of posting.

So I see a few have replied already.

[JanieB]

Oops - I had to call in the middle of posting.

So I see a few have replied already.

Others have beaten me to it. In layman's language you need the semi circle plus the the straight bits that you are inserting into the pipes.

[Bill Door]

Well actually no! It would be better to get the minimum and maximum lengths required and use the excess for something else.

If the width of the bed is 1.75 metres and the metal poles will be one metre in length then the curvature on each side will form a partial circle based on a radius of one metre with an overlap of about 25 centimetres in the middle. So the maximum will be a semicircle with a radius of 2 metres and you will need at least three hoops. The circumference of a circle is 2 x Pi x radius. So 2 x 3.14 x 2 or 12.56 metres so half of that multiplied by 3 is about 19 metres. The minimum would be a 1.75 metre semi circle and three of them would measure about 16.6 metres. As we all know plastic piping does not conform to what we think they will do. So as someone has also suggested you might need to get a couple of bamboo canes(or something stronger) to support the pipes.

One other point is that you may not get all metal spikes one metre into the ground, I know I would be scuppered on my ground.

If you want it more permanent then how about plastic water pipes (non bendable) with plastic joints to join them, glued together. You could also glue support pipes across the top and make it stable?

Good luck

Bill

[bramble]

If your metal posts are 2m (taller than you are) have you thought about how you're going to whack them into the ground?

I love it😂

[Bigmallly]

If your metal posts are 2m (taller than you are) have you thought about how you're going to whack them into the ground?

A Tall Ladder....................

[goodolpete]

Can any one help me please?
I need to know what length of alkathene pipe (tough plastic water piping) to buy to make hoops for tunnels for my veggie garden. They will be 1.75m wide by 4m long in total and about 2 m high (so that I can stand up and work under them - I am 5' 6")
I plan on putting metal pipes in the ground so that 1m is below ground and 1 m above ground. Then to put the water pipe over the protruding metal pipes.
How do I work out the total length of plastic pipe (from the ground, up and over and down the other side) please?
Does any of that lot make sense?
I have some frames covered in a fine green netting and the veggies are protected from the scorching sun and from bugs - veggies are so much better under these, so I want to cover all 4 of my beds in this way.
Thanks

Hi. I've just realised that I need something similar to net my fruit bushes.
How did your project go in the end?
Where did you get the metal spikes from?
What width of pipe did you use - I presume the smallest and cheapest 20mm ?
Best Wishes,
GOP

[Kirk]

At 1.75 wide that is 2.75 for the semicircle. then you need the additional 1.0 for the upright bits so that is as previous 4.75 meter for each "hoop".
Easy solution is simply get the pipe cut into 5 meter lengths and make one hoop with each length.

Height at centre should be 1+0.85, so 1.85 meter at the centre - with the original dimensions, fractionally more if you use 5.0 meter lengths.

Using 5 meter per hoop then if 4 mter long tunnel and at 1 meter seperation per hoop then you would need five 5 meter lengths so 25 meter.

[Cadalot]

How to work it out is explained with drawings here Alans Allotment: Blue Water Pipe & Netting also FAQ section