Tomato Glossary: 35 Terms To Know When Growing Tomatoes

By: Chenell - Lead Writer and Gardening Advocate

Blossom Drop

Blossom drop is essentially the loss of flowers from the plant. This happens when the tomato flower has not been pollinated, the stress of the plant due to not enough water, too much wind, too much pruning, or other reasons.

Some level of blossom drop is normal as not every flower will be pollinated and grow fruit, but excessive blossom drop is something to be on the lookout for.

Blossom End Rot

Blossom-end rot is a common issue for tomatoes that is either caused by a lack of calcium in the soil, or the plant not being able to take in calcium.

Too much magnesium, potassium, sodium, or ammonium salts in the soil can cause the inability of the plant to uptake calcium.

Bush Variety

Bush variety tomatoes are determinate or semi-determinate tomatoes that grow thicker and spread more horizontally than vining tomatoes. They are more compact and usually fit into smaller growing spaces like a patio or container.


Bacterial canker in tomatoes is caused by bacteria and has the potential to take out the entire plant and surrounding plants. Wilting is often the first sign of canker issues.


Catfacing is when the tomato fruits are misshaped with brown stripes of rough, dark brown tissue. Catfacing happens when the flower buds develop abnormally before they blossom. This can be caused by prolonged cold weather below 15 degrees Celsius, too much pruning of the plants, and high levels of nitrogen.

The fruit can still be eaten, and catfacing usually only happens on the first fruits that form on the plant.

red tomatoes on vine


Chlorosis of plants is often caused by a deficiency in iron that leads the plants leaves to start turning yellow and look bleached.


A cluster is a group of fruits on a tomato plant. Indeterminate tomatoes often form clusters of tomatoes, whereas determinate varieties grow fruits all along the stems.


Cotyledons are the first leaves to appear on a plant that has been germinated. Also called the “first set of leaves” for obvious reasons.

Container Varieties

Varieties of tomato plants that grow well in containers because they are smaller and bushier. These are usually determinate or semi-determinate varieties.

Crack Resistant

Crack-resistant tomatoes are varieties that were bred to be less susceptible to forming cracks along their fruits.


Determinate tomatoes are plants that grow smaller and bushier. They produce all of their fruit at once, as opposed to indeterminate varieties that grow tomatoes throughout the season.

Related: Determinate Tomatoes: Differences, A-Z List, & Which is Better?

Foliar Spray

A spray that is applied to the leaves (foliage) of the plant to help with pests or disease.

Frost Dates

The first and last frost dates are different around the world and correspond with your local climate. After your last frost date, it’s generally a good time to transplanting or growing seeds outside.


  • Also called green shoulders or yellow shoulders

Greenback is when tomato fruits don’t fully ripen and end up with green or yellow coloring at the top of the tomato. This is due to high heat and even overexposure to sunlight. When pruning plants, new gardeners might prune off all the leaves, but this removes the shade for the fruit as well.

Hardening Off

Hardening off is the process of allowing seedlings that were started indoors to adjust to the outside world before transplanting them outside. This helps reduce transplant shock of the plants going from perfect conditions to brighter sunlight, more wind, and pest pressure.


Indeterminate tomatoes are varieties that grow fruit throughout the season. They usually grow between 6 and 10 feet tall and are also known as vining tomatoes.

Related Post: Which Tomatoes are Indeterminate? A-Z List of Indeterminate Varieties


Locules are the cavities inside of the fruit when it’s cut open where the tomato seeds are developed.


Maturity is when the plants produce their fruit. You often see “days to maturity” on the back of seed packets, that let you know when you can start to expect fruit from the plant.

Mosaic Viruses

Common viruses that impact tomato plants and can lead to reduce yield, misshapen leaves, or mushy fruits. The two common mosaic viruses in tomatoes are:

  • Tobacco mosaic virus (TMV)
  • Tomato mosaic virus (ToMV)

These can be spread by thrips, aphids, and infected plants that were transplanted together.


NPK is the ratio of main nutrients in fertilizers:

  • N stands for Nitrogen
  • P stands for Phosphorus
  • K stands for Potassium

An NPK ratio of 3-3-5 means there are 3 parts nitrogen, 3 parts phosphorous, and 5 parts potassium.

Potato Leaf

Regular Leaf



Semi-determinate tomatoes are a mix between determinate and indeterminates. They grow bushy like a determinate plant, but produce fruit throughout the growing season just like an indeterminate plant.

Spindly (Leggy)

Spindly or leggy seedlings are those that are brittle and not as sturdy as stems should be. This can be caused due to excessive heat during early days of germination, as well as a lack of sunlight.

The plants “stretch” to get closer to the light source, and end up getting spread too thin – see what I did there? 🙂


When you stake your plants, you’re offering them some support as they grow. Tomatoes usually need more than a stake and are often growing along a trellis system (see below).


The base of the plant along which all other branches and shoots form.

Suckers (Side shoots)

Tomato suckers, also called side shoots, are new shoots trying to form between a branch and the main stem of the plant. While they can be left alone and the plant would do fine, they are often pruned off indeterminate plants as they steal energy from the plant that would otherwise go towards producing fruits.

Tomato Cage

A tomato cage is a support structure that helps tomatoes grow upright instead of falling over due to excessive weight from the leaves and fruit.


A trellis is a structure that helps support climbing plants like tomatoes and cucumbers as they grow tall. The basis of a trellis is usually some sort of mesh or lines of string/twine attached to stakes on the edges.

Related Post: Florida Weave Trellis: The Best DIY Trellis Method


A truss is a cluster of stems where flowers form and the tomato fruits grow. Usually seen on indeterminate tomato varieties, trusses start to form around 40-60 days after being planted.



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