It means cutting out some of the smaller branches. In some species new plants try to grow from the base of the established plant. They are like new plants trying to live off the established plant’s roots. This doesn’t really happen with tomatoes. “Suckering” tomatoes is a waste of time unless you have a shortage of water or a shortage of light. In those cases limiting vegetative growth might actually give you a better yield. Otherwise it just limits your harvest. Ie: Bad idea in most cases.

If you are like most back yard gardeners...or a commercial grower, you never have enough space to plant...so plants are always a bit closer than optimal. Why waste water and nutrients? You can also remove any limbs that are low on the plant when young ...to reduce chances of disease.

Since you don't have to hire crew to come in to do an entire field, you have the luxury of suckering continuously. You should do so when they are still try like this one (see arrow) although you certainly can when larger (like the one the finger points to). When they are larger, they have already wasted some of the plants energy and weakened the limb slightly. If you have larger ones and want to, you can put the removed suckers in a jar of water in the sunlight and they will grow roots. You can plant them for a late season crop in another bed.

http://forums.pelicanparts.com/uploa...1523840442.jpg

You can see how the added limb not only begins to take over from the original larger one, but also adds stress to the joint. Sometimes the original (lower) limb just begins to die or turns yellow. Don't do this..or touch the plants (if you can help it) when they are wet...as it tends to spread disease.
http://forums.pelicanparts.com/uploa...1523841329.jpg
http://forums.pelicanparts.com/uploa...1523841329.jpg

I have known about taking off the lower branches since I was a little kid, actually just did that with a few tomato plants I got out of a six pack, put one of them in a big gallon container, it had such a long stem on it. I need to get some chicken wire so I can keep the dogs out of there.

I've been thinking about my tomatoes for a while now.
My biggest problem is a maple tree is getting bigger and blocking the light.
Anyone ever use grow lights outdoors?

Come on man, you are in Canada, they have been growing rope indoors for a while up there.