Hmmm, I actually just built my first Sq Ft garden. Two 4x4 boxes, and built a trellis on each using 1/2" conduit myself. Being that mine are only 4' spans for the top support, they seem really strong and I will be growing melons on one.
Since you are joining two 4' lenghts in the center, I would assume(yea, yea, I know about assuming) that you might run into problems with weight on that long span.
Maybe you could find a 3 way conduit connector, join the two 4' pieces like you described, and then run another length of conduit down the middle to support the structure.

That's what I was initially planning but I couldn't find a 3 way connector. Do they exist?

Didnt think it would be so hard to find but I found one here for ya, at least they do make them

http://www.indiamart.com/superimpex-electrical/electrical-accessories.html#conduit-accessories

It does look promising but the shipping from a company in India would be murder. I searched the web too and couldn't find anything - so you did better than me :) . I guess I might just make the trellis 4 foot long and just put 2 on each of my beds. That way I have peace of mind.

That sounds like a good idea. It would be horrible to come out to your garden in August and find you trellis toppled with crushed Veggi you worked so hard to grow.
Didnt notice it was a company in India by the way...sorry bout that

They have three way connectors. Call around to local hardware stores in your area or call plumbing companies to find out where they purchase parts.

I called around to a few places and actually went to Home Depot today. The only three way connectors they have are copper, brass and pvc. I'm unsure of how I could connect these to unthreaded electrical conduit (I have no way to thread the conduit at this point). I was hoping for a screw mechanism to tighten the poles in place like the corner pieces.

I can help with this one...

First off, is the conduit you purchased to make your trellis the thin-wall type (called E.M.T.) or is it the heavy-wall rigid conduit which has to be threaded to be joined together?

Assuming it is the thin-walled type, yes, there are fittings you can purchase to join your middle support. Go to any Lowe's or Home Depot and in the electrical dept, ask for a "Set-screw tee condulet." It has an opening on three sides to accept the conduit, as well as a removable cover which is held on with a couple of screws. It will look somewhat bulky on your trellis, but it will do the job. Be sure you get the correct size for the pipe you used (1/2, 3/4 trade size) Be careful, there are also tee condulets which will accept the threaded rigid conduit. If all you can find is a rigid tee, it can also be used, but you will need box connectors for the three openings to thread into the condulet. It will then have the set-screws to connect to the conduit.

When I built my trellises, which are 6' long, I used a conduit bender to put a 90 deg. bend on each end of the conduit, then used couplings to join them to the vertical supports. I used the 1/2" thin wall type, and it is plenty strong enough for anything I grow on it, incl. beans, tomatos, cukes, melons, etc. If I were going 8', I think I would go to 3/4" thin-wall conduit.

I must admit, I have a slight advantage at bending the conduit, as it is what I do for a living! If you know an electrician, he/she can help you make your bends on your conduit. Having one solid piece of conduit for the horizontal will give your trellis much more strength, IMO.

TheBug

Thank you soo much for the information! I am using the thin wall conduit since the thick wall stuff was a lot more expensive and we have 4 - 8 foot and 2 - 4 foot trellises to build. It's 1/2 inch diameter. I'll make a pit stop at Home Depot tomorrow and see if they have that there. The sales person assured me they had nothing to make a 'T' connection that tightened with screws. I have a feeling he didn't understand what I was asking. It will also help having DH along with me so I can browse while he watches the baby.

Once I'm done the trellises I'll post pictures and then report back at the end of the season if they survived :)

Thanks again. Linda

I also looked for a 'T' for EMT conduit .. no luck. Home Depot didn't carry it, neither did OSH and neither had a suggestion as to where I could get one. The only 'T' connections I found were for copper pipe and PVC. I didn't want to make the trellis out of PVC at the time, but if I had it to do all over again I might. 1' schedule 40 is sturdy enough. I have 6' long beds so I would have had vertical pipe on the ends and in the middle and also horizontal at the top and bottom. I think that would have been a strong trellis.

I would have loved to make the trellis out of copper pipe, but that was way too much money.

I ended up buying 3/4' EMT electrical conduit; two 10' lengths per bed. I bent the pipes 90 degrees at 7' and then connected them at the top of the trellis with screw connections. Since my beds are elevated off of the ground 2', the actual trellis is 5' high and 6' wide. I attached the verticals to the beds at 2', so that added to their stability.

My blog has pictures.

jmaellis-sfg.blogspot.com

Here is a link that might be useful: My SFG blog

The copper tee is a good idea... however, over time the two dissimilar metals will react with each other and you will get a lot of corrosion as a result. Could end up with rust stains running down the vertical support under the tee. If you can somehow isolate the two metals with something, you shouldn't have too much of a problem.

TheBug

Well I went back to HD on Saturday and asked specifically for the 'screw set tee condulet'. The guy said he's never heard of them and tried to direct me to the 'L' shaped ones. *sigh* anyways after he left, my husband I found a box of threaded tee condulets and got the adapters. They aren't as big and bulky as I was fearing. They actually look kind of nice. I assembled almost all of my trellises yesterday and will install them this week. Thank you so much for all your help everyone! I'll post pictures of the finished product so that it might help others with the same problem.

I'm using the EMT conduit and I did manage to find a three way connector. They don't look like you would expect them to and finding someone to give you any help in Home Depot here is a complete joke, but after about half an hour of reading the tiny labels I did find one. It looks like a big oval with screw connectors on three sides. I've reinforced my conduit with an upright every four feet. Should be sturdy enough for melons by the feel of it. So glad you found what you were looking for.

It's been awhile, since I put mine together, but I just pounded in 2 pieces of conduit (to the same level), in the corners of my 4ft raised bed, then got 2 "eye screws, big enough for a third piece of conduit to fit through the eye, dropped the screw part into the 2 uprights, and stuck the 3rd piece through the eye part. (The top piece of conduit is left longer than the width of the trellis.) Then I wired a piece of fence to this frame. Once in a while, I would have to tap one end of the top piece to center it again. It looked okay, and worked fine for peas and cucumbers. I don't doubt that it would have worked for melons, but I never did mine that way.

I worked around electricians for nearly 35 years and, was pretty familiar with their fittings. I've priced all of the "Tees" for putting my trellises together. Whew! They"re expensive.

I finally decided to use 1" thin-walled conduit and, wherever the pipes crossed, I drilled a hole though both pieces of conduit, stuck a galvanized nail through both holes, and bent the nails so they wouldn't back out. The reason I chose 1" pipe was because of the possibility of holes I drilled creating a weak spot. I was able to make long runs without having middle supports.

My neighbor liked my design and was gonna make the hole-drilling easier by starting the hole with a punch. Well, he never did use the drill. He was able to punch clean through with the punch. Lining up the holes just right was the issue with the punch method.

The nails act as a hinge allowing the frame to be pulled up and sorta "folded". This idea sounded good to me when I built the frames but, I've never pulled them up. With our mild winters, I can grow the entire length of my trellises in Sugar Snap Peas all winter long. So, my frames stay in the ground year-round. I actually yank peas in the spring (that are still producing) in order to plant cucumbers and melons.

I drove the 10-foot vertical pieces into the ground about 2-feet. This set-up has held-up through violent winds and very heavy crop weights. Wire fencing with 4" or even 6" squares makes a perfectly strong trellis for cukes and melons to hang onto.

It took me and my 11-year-old granddaughter about 2 hours to build and install 4 frames 8-feet long and, 8-feet tall.

I have no experience with this type of trellis, but whenever I have pipe with two joined pieces bending at the joint I stuff the interior with rebar of an appropriate diameter and length.

In your case I would use whatever diameter fits most snugly in the pipe and use at least a 2' length.

If it were me though I would replace the top bar and use a solid length. Having a joint in the middle where all the weight is being supported is structurally weak.

I ran a 8 ft horizontal section 1/2". In the middle I ran vertical peice up to the cross peice. I drilled a hole about 1" from the top of the vertical pipe. put a zip tye through it and over the 8 ft cross pipe. Pulled the zip tye tight and ta-da there is now a strong support in the mid section. So far it has worked good.

I was exploring Mel's idea of sticking rebar in the ground -- and then putting the conduit over the rebar. The employee/also electrician at Home Depot advised me to get a special driving machine to pound the rebar in. Have you found this to be necessary?

I was exploring Mel's idea of sticking rebar in the ground -- and then putting the conduit over the rebar. The employee/also electrician at Home Depot advised me to get a special driving machine to pound the rebar in. Have you found this to be necessary?

Further he suggested if I use the less expensive indoor EMT Conduit -- I should paint the conduit to make it last longer. Have you painted yours -- and how is it holding up? Perhaps it's worthwhile to get the sturdier and pricier conduit??

>>The employee/also electrician at Home Depot advised me to get a special driving machine to pound the rebar in. Have you found this to be necessary?Oh, not at all. You are using a short piece of rebar, and just a few of them at that. All you need is a scrap of 2x4 to put on top and a big rock or hammer to pound with. Maybe mark your rebar at the depth you want it to end up.

"I was exploring Mel's idea of sticking rebar in the ground -- and then putting the conduit over the rebar. The employee/also electrician at Home Depot advised me to get a special driving machine to pound the rebar in. Have you found this to be necessary?
Further he suggested if I use the less expensive indoor EMT Conduit -- I should paint the conduit to make it last longer. Have you painted yours -- and how is it holding up? Perhaps it's worthwhile to get the sturdier and pricier conduit??
"

We just used a scrap piece of 2x6 as a striking plate for the sledge hammer. I held the piece of wood on top with one hand, the rebar with the other and my husband wacked it with the sledge. Took some time to but it wasn't hard.

We used regular el-cheapo conduit. No painting. Once vines are growing up it you can't even see the conduit or the trellis material for that matter.

I just used a rubber mallet on my 4' rebarb and we have clay soil it was no problem.

Here are some pictures from last year. These were taken right after I installed them.

[IMG]http://i12.photobucket.com/albums/a243/linny123456789/new%20pictures/May%2020/DSC_0048.jpg[/IMG]

Shows how I secured the netting to the conduit:
[IMG]http://i12.photobucket.com/albums/a243/linny123456789/new%20pictures/May%2020/DSC_0053.jpg[/IMG]

Stuff starting to grow up:
[IMG]http://i12.photobucket.com/albums/a243/linny123456789/Jun%2007/DSC_0210.jpg[/IMG]

[IMG]http://i12.photobucket.com/albums/a243/linny123456789/Jun%2007/DSC_0231.jpg[/IMG]

I don't have any pictures uploaded that show the trellises completely covered with vines and tomatoes.

I have been sq ft gardening this will be my 3rd season and 2nd with a trellis and you do not need a middle support if you use elec conduit and cattle panel cut from 16' to 2 8' pieces. See my pics
[IMG]http://i167.photobucket.com/albums/u155/twobars/007.jpg[/IMG]

[IMG]http://i167.photobucket.com/albums/u155/twobars/003.jpg[/IMG]

Well if you do use cattle panel, you can just use metal fence posts (the kind you just hammer in) to mount it. That way you don't have to worry about cutting conduit and hammering in rebar. I would have used cattle panel but have no where to buy it.

I am using 3/4" EMT also. Is it absolutely necessary to use rebar imbedded in the ground? I had planned on securing the upright segments of the trellis to the sides of my box using several conduit straps, after driving the conduit into the ground a couple of feet.

I am using the 1/2" emt conduit. I did the rebar pounded into the ground, as I felt that was easier than attaching it to anything or driving the conduit into the ground.

In addition I spray painted it with brown rustoleum for a couple of reasons. Mostly just because I didn't want big shiny metal things in my garden.

[IMG]http://i611.photobucket.com/albums/tt196/jwstell42/050609048.jpg[/IMG]

Let's try this picture thing again :)

{{gwi:1273152}}

Securing with rebar or similar is much easier and more flexible. I also use PVC sleeves.

Dan

What size rebar should I buy for 1/2 EMT conduit and what length? My raised beds are about 1' deep before the natural clay soil. How deep should the rebar go in to the natural soil and how much should be exposed to be sturdy enough for cukes and sugar baby melons?

Your inside diameter of the conduit is 1/2. You want rebar smaller than that. I prefer the 3 ft because it is windy here and the tomato & cuke trellises git a-rockin'. I leave ~8 in above ground.

Dan

Linda,

I built my frames almost like yours, only cut into 7' and 3', connected the the 3' sections. I put them 1' into the ground. Making a 6' high and 6' wide frame. I have grown 6 tomatoes under 1 and have no problem with them holding up. I have not grown melons or heavy fruit on them. Just my opinion, I would not put more than 1 melon plant per trellis and then use the rest of the space on it for beans or cukes. My first frame is over 12 yrs old and just starting to rust (and I have not been good about taking them in over the winter).

Good gardening, Mary

"T" for Electrical Conduit

If you want to make a longer/wider electrical conduit trellis (eg 10 feet wide) then you may want to use a "T" to connect the top bars of electrical conduit. You would need the following parts (I bought at Home Depot):

1) Conduit Body "condulets"
Part #: E121488 1/2" T

2) Halex EMT 1/2" "Metallic Set Screw Connector"
Halex Part#: 26270

I didn't think a "T" was available for 1/2" electrical conduit, but after spending an hour in Home Depot's electrical department I found the above parts work great.

About 7 years late but I saw the thread and thought I would contribute a link for a more cost effective T connector. Maybe it will help someone. http://www.buildmyowngreenhouse.com/12emtconnectorsandclamps.aspx

I am planning to build 2 of these. I wanted to ask linnyhb what the connectors he used that connected his end panel and side panel together. I can't seem to find them. I know it's not a "T" and it's not a 90°....I need to find out what that corner fitting is. It's a 90° on top, but it also have the hole for the vertical pole coming up. I have seen them in PVC fittings...could I use PVC corner fittings on my ½" EMT conduit? I'd drill a hole in the fitting and insert a screw to tighten it to the conduit.

Years later, found this solution for connectors: https://makerpipe.com/collections/modular-pipe-fittings