Check your math too. 5 foot length of fence only gives you about an 18-19" diameter cage if I recall correctly. Not big enough.

Most folks use rebar driven in the ground and wired to the cage.

Probably 8 cages will be wide enough (~ 22-23" in diameter, with one grid overlap)). As Dave pointed out if you make 10 cages they will be 18" in diameter.
To nail it down, like mentioned, you can use a variety of stakes. I use 2x1 cedar, b'c that is what I always have and it is cheap.
A 23" cage should be pretty stable sitting on the ground by itself. but you want to make sure that high winds won't topple it .
Sey

Tent Stakes. Been using them for years. Use 4 per cage and at the end of the season remove them and use again the following year. Here is a link as an example what to look for.

http://www.amazon.com/Coghlans-Tent-Stake-Bulk-12-Inch/dp/B002JG73SU/ref=sr_1_29?s=outdoor-recreation&ie=UTF8&qid=1429872172&sr=1-29&keywords=Tent+Stakes

If your plants grow as they should you are going to need to stake the cages or they will fall over. No amount of wire in the ground will prevent this. I rip an 8 ft 2X4 in half and stake each cage with a 2X2 driven into the ground about 2 feet. An added bonus is you have something to tie the top of the plant to when it outgrows the cage if needed.

I use 5' T-posts and zip tie the cages to them, one post per cage. Easy to clip off if you need to move them, and gives plenty of support for the high winds we can get.

I just used a roll of 5' remesh (CRW), finishing my cages yesterday. I found 20" a nice compromise. 18.5" was too narrow for my liking. Doing it efficiently, I'd get per 50 feet:

Option 1: [ten 18.5" cages the way you suggest] or

Option 2: [eight 20" cages plus one 22.2" cage] or

Option 3: [one 18.5" cage, six 20" cages and two 22.2" cages].

I would choose option three for my purposes, to accomodate my selection of plants. Following the trend in option 3, the way it shakes out: for every 18.5" you add, you get another 22.2" cage. If you wanted all big cages you get four 22.2" cages and four 23.8" cages. Don't waste any material, utilize the mesh to its fullest extent. In all cases spend some time rounding the cage, I found that made the difference when using 20" cages.

PC

Thanks for all the suggestions folks... I like the notion of using tent stakes- I have a bunch of those. I'm dithering around with the notion of making 8 cages instead of 10 now. The cages are for determinate dwarfs that are supposed to top out at a max of 4 feet tall... but it might be the better idea to make the larger cages so I can use them more effectively another year if/when I'm not growing small plants.

Beesneeds,
With determinants , you can cut off 2 rows of horizontal wires, exposing legs of about 10" long. When all those legs pushed into ground a 22' DIAMETER cage should be pretty stable, even without any anchor.. But go ahead use those tent stakes anyway.

Sey

So I got cages built today- I found 6 foot tall fencing for only 4 bucks more than the 5 foot tall fencing. Better too tall than too short I figure- who knows what future years tomatoes will grow out to?

I took the suggestions to only make 8 cages instead of 10 out of a 50 foot roll. Since the squares on the cage were 2x4", some cages were snipped at 6 feet, some at 6 foot 2 inches- I snipped so that I would have the extra inches as "legs" for wrapping around the squares where the ends met up, and it worked out perfectly.

And put the cages into place- nice thing is, they really bring to fore just how much space to allow for my plants! Or rather, the spacing Im using for my plants. Wasn't expecting that bonus.

I got foot long tent stakes to pin the cages down with, but haven't pinned them down yet because I'm not putting the tomatoes into the ground till after the weekend- it's too chilly to do it right now, and I gotta work for the next few days.

2x4" does not give much room for your hand to reach in and pick the tomatoes.

I am fortunate that I have tiny hands and wrists, and can easily reach into a 2x4 square- I can actually reach almost up to my elbow in that much space- and if I need to, I will snip out a couple bits to make bigger access holes as needed. I will decide on some stagger in holes in a later date when I need to- to accommodate the tomato size, not my hand size.

And since I'm a bit over 5 foot tall, even if I get a whopper tomato and need to hand it up to the top of the cage, that's still within my reach. But with my planning, the beefsteaks are trellised on the fence, and it's more like the plums and baseball sized at largest in the cages.

I've gotten used to reach in and pick in the squares provided in chain link fencing, lol. I can strip a bean fence clean no problem from one side, reaching through the holes in the fence.

On the down side, I have such tiny hands that I have to find childrens sizes in gloves- no easy task, since most kids gloves are "lightweight" use compared to my "ultra heavy use mans hands" type usage I get out of gloves. Even with standard cloth gloves, it is easy for me to reach into a 2x4 square.

I am using a metal fence post at each end of the row of tomatoes and will weave rope through the tomato cages (5 foot CRW). Additionally, we get high winds rarely. This is my first year, so I will report later.
Regards,
Tom

I agree that the 2x4" openings of 6' tall fencing can work well. With a few strategic cuts you can easily make 4x4 or 4x6 holes for harvest. With the ones I made years back I found you do have to trim back some extra leaf branches for good air circulation within the cage. They tend to compress more of the branches inside the cage due to the smaller openings than with the CRW cages. But the extra height is nice.

Oh and watch those cut edges - sharp and got the cuts to prove it. Cut the wire a bit long and bend it back for a smooth edge.

Good advice Dave, and what a gorgeous garden! Are you still in the same place now?

Very good conclusion.

On the cage height: If you want it 6ft tall, just put it in place (no horizontal cutting) and support it with some kind of stakes (wooden, rebar ..). I had one 4 ring that is what I did with. If I had to make it firm, I had to push the legs into the ground by more than a foort But I just pushed the legs few inches in. Then I drove few stakes real deep and tied the cage to it. Now I have 5 ft tall cage. Good enough for a 4- 5ft determinant.

Sey