Tomato plants thrive here, where I take up housekeeping. So much so, the small cages sold in stores are all but worthless.
Years ago, I made my own cages from fencing I had on hand. The fencing was about for feet tall and the openings were all about six inches square. The fencing made perfect cages for the huge plants that grew in truck tires, from which I'd removed all but a couple inches of the upper sidewall.
I found myself needing large cages again, but all the "perfect" fencing, like I'd used, required I buy a large, expensive roll. However, while wandering one of the big box stores, I did come across a roll of fencing three foot tall and about fifty feet long for around $30.00.
Though the recently found fencing had holes too small to reach through [and pull out large tomatoes], the holes can be enlarged at random points about the finished cage to make accessing the plant and its fruit easy.
To build these cages, you'll need:
1) Fencing (available from big box stores, hardware stores, garden supplies, etc.).
2) Wire cutters large enough to cut the wire, side cutters or a small bolt cutter.
3) Two pair of pliers
3) A pair of pliers and channel locks
3) A pair of pliers and the side cutters used to cut the wire.
Step 1: Cutting the Fencing to Length
Whether your pot is round or square, you need to determine how big to make your tomato cage.
1) If your plants will be grown in a square pot with, for example, a pot with 20" sides, your cage needs to be a little less than twenty inches on a side to fit in the pot.
2) If your pot is twenty inches, you need to measure twenty inches for each of the four sides (4 x 20"), then subtract an inch for each side (80" - 4" = 76").
3) When cutting the individual wires, leave about 3/4" beyond any piece of wire ninety degrees to the wire being cut. This is necessary for securing the two ends. It will be used to rap around the other end.
1) If your cage will be used in a round pot, you must determine the circumference of the pot. To do this:
a) Find the diameter of the opening of your pot. To do this, measure across it. This can be done by holding the end of the tape measure at one point on the pot, then pivoting the opposite end of the tape off that point, until you get the maximum reading for the opening.
NOTE: Because the cage must be smaller than the opening of the pot, you can reduce the diameter by "burning" the first two inches on the tape to, essentially, remove an inch off the perimeter. That is, instead of using the end of the tape for your pivot point, use the two inch mark as your starting point. Alternately, you can just subtract two inches from the diameter.
b) Multiply the diameter by pi (3.14). So, if you arrived at a diameter of twenty-four inches (24"), you would multiply that by three point fourteen for a result of seventy-five point thirty-six inches (75.36").
2) Once you have your measurement, layout your fencing and cut it to the length your came up with for your growing pot or area. You MUST leave approximately three quarters of an inch (3/4") of wire sticking out from the squares near where you are cutting. You will need the wire to tie the ends together. Otherwise, you will have to use additional pieces of wire to tie the ends together.
Step 2: Tying the Ends of the Cage Together
You will need two pair of pliers or the equivalent. You might find channel locks work better, to crimp the wires, since they provide more leverage. You still need the second pair of pliers or channel locks, so you can hold the side you are twisting wire around.
1) Connect the two ends of the fencing together and align them.
2) Bend a wire you cut and left long around the wire joining it [from the other end]. Use the pliers or channel locks to wrap the wire until no sharp edge is sticking out.
3) Flip the fence over and do the other end, then work your way back to the first. Again, bend the wire until no sharp protrusions extend where they could cut or scratch you.
NOTE: If you find the 3/4" length you left when cutting the length, you can cut off a little more, but leave enough to get a complete wrap around the wire you are tying to.
Step 3: Enlarging the Openings for Access to Tomatoes
Choose random points around the cage for your enlarged openings. Five openings may be all you need, but you may decide to open more. Just leave plenty of links between openings to maintain the structural integrity of the cage.
Leave about 1/2" wire beyond where it connects to one of the squares so you can double it back, to avoid sharp edge around the openings. Again, crimp it until it cannot scratch or cut you.
Of course, when done with one hole, move to the next spot you want to open up. Use the last hole you opened up to determine if you want the hole larger or smaller and tackle each hole according to what you feel will work best.
Step 4: NOTES and TIPS
1) If you bury the bottom of the cage a few inches deep, it will help stabilize the cage once it has the weight of the plant on it.
2) Tying a string to the cage and planter on each side of a square cage, or at four points equally spaced on a round cage will protect the cage from being blown over in the wind.
If you are growing the plants directly in the ground, you may want to consider driving stakes in the ground and tying the cage to them, if wind is or could be a problem.