Desperate Gardener: Tomato Tuesday: Pruning Tomato Plants

Disclaimer...alert...warning...heads up:

There are many theories on growing tomatoes. Unfortunately, there are no hard and fast rules. What I share with you are things that have worked for my Grandma and I in the past. My goal is to provide you with the theory behind pruning, so that you can make the best decision for your plants.

First step: Determine if your plant is determinate or indeterminate.

Determinate: Also known as bush plants, will eventually produce all of their fruit at once and stop growing. The best way to tell if your plant is determinate is that it will produce a cluster of blossoms at the top/center growing point. This stops the plant from growing. Typical determinate types are: Roma, Patio, Celebrity, anything that has the word "bush" in its name.

Roma Tomato-determinate

Indeterminate: Also known as vine tomatoes, will keep producing fruit throughout the summer until frost eventually kills the plant. Typical indeterminate tomatoes: Beefsteak, Yellow Pear, most heirlooms, Brandywine, Early Girl, and Cherry Tomatoes.

Rambling Red Stripe-indeterminate

It is not necessary to prune determinate tomatoes, only indeterminate.

By pruning your tomato plants, you are helping your plant shift its energy into producing larger, juicier tomatoes.

Second step: find the suckers:

Suckers are branches the tomato plant develops for stability and if left to grow, will compete for energy and nutrients with the main stem and the side branches. If you have properly supported your plant with stakes or a tomato cage, your plant does not need the suckers.
Although leaving the suckers on will result in more blossoms and fruit, the fruit will be smaller and may not ripen.
My philosophy involves pinching off the suckers which results in fewer tomatoes, but my tomatoes are always large and yummy.
I also grow more tomato plants to account for the smaller fruit production. I have over 15 plants growing on our tiny lot. They are in hanging baskets, 5 gallon buckets, in the garden and out on the area between the sidewalk and the street. I even have some growing inside.

A sucker is a branch that grows out from the main stem and a side branch . Simply pinch these off as they grow.

The sucker is the branch growing at a 45 degree angle (going up):

Shows pinched off sucker:

Can you spot the sucker growing?

Blossoms:
This is a tough one. Some people do not pinch off blossoms and have success. Most of those people live in areas with longer summers and warmer evenings. In Seattle, our tomato plants are exposed to stressful conditions such as cool evenings, rain, and wind. This can cause the plant to become stressed and prematurely blossom.

So how do you know when to pinch off the blossoms, when not to, and when you should stop pinching off the blossoms? Bottom line; if the plant looks like it's big enough and sturdy enough to support a tomato than it is, so stop pinching the blossoms.

Too vague? Here are some general rules I follow:
Pinch off blossoms if:

You've planted your tomato plant less than a month ago.
You live in a climate that has extreme growing conditions that would cause your plant to prematurely blossom. Such as:

Temperatures at night are below 50 degrees.
There hasn't been consistent sunny days.
It has been over 80 degrees during the day.
It has been rainy or windy.
You forgot to water your tomato plant for a few days, and blossoms appeared.

Your plant is less than a foot tall.
Your plant is over a foot tall but "leggy".

This plant is tall enough, but very leggy and weak looking. I have pulled off a few blossoms to let this plant gain its strength:

This one looks good, I may pull a few suckers, but I will let the blossoms be ( I also will admit I have no idea what kind of tomato plant this is!):