Have you ever heard of anyone growing tomatoes on a horizontal
trellis?  Sort of like grapes and kiwi are grown?  I'm curious as to
how that might work.

A horizontal system should work great. I can think of a couple
things to keep in mind. Grapes and kiwis are long-lived woody
plants, so it makes sense to build a sturdy, permanent trellis
structure. Tomatoes, on the other hand, are grown as annuals and
it's best to rotate them to different places in the garden each year
to help minimize pest problems and soil nutrient deficiencies. So
you'd want a trellis you can move each year. 

Also, grapes are usually pruned to two horizontal wires; you might
want to have more horizontals to maximize production. You want to
make sure there's plenty of foliage on the plants so they have
energy to produce tomatoes -- and so the tomatoes don't get
sunburned.

I would also be concerned about using metal wires to support the
tomato vines. Unlike grapes vines, which are woody, tomato vines are
soft and might be damaged by wire supports (which would also get hot
in the sun). A neighbor of mine uses long lengths of electrical cord
-- like you'd find on a lamp -- between trellis posts and it seems
to work really well. It's strong, flexible, and the metal wire is
encased in plastic which keeps it from getting too hot and from
cutting into plants. It's economical if you can buy it in bulk from
an electrical supply store, and it can be reused for years. Use
something soft -- strips of fabric, for example -- to tie the tomato
vines to the horizontal wires.

If you decide to try this system, please post another message and
let me know how it works! Take some photos, too! 

I'm growing tomatoes from seed for the first time and while the
plants are growing quickly under their grow lights, some of the
leaves are turning yellow. I'm thinking they need something, but I
don't know what. Any suggestions? I heard from a colleague that
perhaps fish emulsion would help. 

Yellow leaves on seedlings can indicate a number of problems. Here's
a quick list of what your tomato seedlings need, which might help
you decipher the cause of the yellowing. 

Nutrients: Most soilless seedstarting mixes don't provide much in
the way of nutrients. Seeds contain enough stored nutrients to allow
them to germinate and send up their first set of true leaves; after
that, the plants need to begin gathering nutrients from the soil or
some other source. If you haven't done so already, begin fertilizing
your seedlings. A fish emulsion is OK, but a fish emulsion/seaweed
mix usually contains a broader range of nutrients. However, as much
as I'm an advocate of organic fertilizers, I must say that fish
emulsions can be quite... fragrant. So look for one labeled as
"odorless" if you are growing seedlings in a living space. Follow
dilution instructions on the label. I like to start with a
half-strength solution until the seedlings are growing vigorously.
Water at the soil line, or better yet, from below, to avoid wetting
foliage. Although most fertilizers can be applied as a foliar feed,
seedlings are so delicate and susceptible to disease problems, I
think it's best to keep foliage as dry as possible.

Light: Be sure the lights are suspended just an inch or so above the
tops of the seedlings. Light intensity diminishes with distance, so
either prop seedlings up or lower the lights as necessary.
Insufficient light can cause pale, leggy seedlings. Keep the lights
on at least 16 hours per day. If the grow lights are several years
old, consider replacing them -- their intensity diminishes as they
get older.

Water: Too much or too little water can cause yellow leaves. Keep
soil just moist -- not soggy, not dry. You can let the soil surface
dry slightly between waterings. 

A few other things to keep in mind: Air circulation helps minimize
disease problems, and a gentle breeze from a fan has been shown to
produce sturdier tomato seedlings. Hopefully, you used a sterile
seedstarting mix; if you used soil from your garden, you may be
dealing with a combination of poor drainage and disease problems.
Make sure plants don't get rootbound. Transplant them to larger
containers when you see roots poking through the bottom of the pots.
As soon as possible, begin exposing your plants to increasing
amounts of direct sunlight over the course of a few weeks. Start out
by placing plants in a spot with filtered sun for an hour or two for
a few days, and increase their exposure slowly to harden them off.
Be prepared to protect plants during chilly weather and don't
transplant until after your last frost date. But as good as they
are, grow lights just can't compare to the the power of the sun!

I have been growing a tomato plant, upside down, for about 5 years. 
I take an old hanging basket, punch a hole in the bottom, line the
hole with porous cloth to keep the dirt in.  Push the root of the
tomato up thru the bottom of GOOD soil and OLE! that`s it.  You must
water almost daily though & put in a little fertilizer.

I'm hearing so much about these upside-down tomato plants I'm going
to have to give it a go this summer. Unfortunately, our porch is
shaded so I may have to put in a post or something.

We have tomato plants that are about three to four feet high, and a
Cardinal has been stripping the upper branches of leaves, leaving
branches with ugly stubs.  I never have seen this before.  Does
anyone else have this problem, and how can we stop it? 

Thanks for any suggestions.

I have never heard of this happening -- how frustrating! You might
try a combination of tactics to discourage the behavior, such as
spraying repellents and hanging inflatable "scare eye" balloons. Or,
string up some foil pie plates so they rattle in the breeze. You
could also cover the plants with a lightweight row cover. And try to
get a photo of this strange behavior.

Thanks for your suggestions.  My husband has put stakes into the
ground all through the bed, and tied cut cloth strips, hanging from
strings all through, and today I saw not only the male Cardinal in
there, but he brought his "wife" with him!  LOL! I don't know what
happened to the leaves, because they are not around.  Is it possible
they are used for nests?  This really is the strangest thing, and I
never have seen this before now.  He is ruining the looks of the
plants.

I was curious so I checked Cornell's All About Birds Web site, and
it says that the cardinal's nest is "an open bowl of weed stems and
twigs, filled with leaves and grapevine bark. Lined with grass.
Often contains paper or plastic in outer layer. Placed in thick
tangle of vines or twigs in a shrub or small tree." So it's possible
your cardinal visitors have decided to line their nest with tomato
leaves. Let's just hope this behavior ends when the nest is through!

In response to Sharon's question about trellising, here's how we do
it (well, my husband does most of it). ;) We use concrete
reinforcing wire (looks like fence, but is heavier and uglier) that
has about six-inch squares. We use 10-foot long steel rods as our
stakes. (He got this stuff at a nearby metal scrapyard). We put the
wire up as soon as we plant the tomatoes, and yep , we use a
stepladder to reach the top when driving in those long stakes. When
in place, our wire stands about 5 or 6 feet tall. Our tomatoes
generally get 6 to 8 feet tall. We prune each plant to 2 or 3 stems
and then just weave them up through the wire as they grow. Sure
beats bothersome tying! By the way, this won't work with determinate
tomato plants.