What's the difference between "indeterminate" and "determinate" tomatoes?

A Celebration of Heirloom Tomato Varieties from Around the World


Tomato Growing FAQ's

Are there different types of tomato leaves?

Yes, There are two leaf types, Regular (RL) & Potato Leaf (PL) and there are also leaf variations for both types, (Rugose-a darker green rough-surfaced leaf, or Angora--a fuzzy, hairy type regular leaf.)

Regular Leaf is the most typical leaf type with leaf edges that are serrated. There are many variations in terms of size of leaf and leaf color with various shades of green or green-blue tint. Some leaves are very narrow and are sometimes called dissected because they look like a saw tooth cut them.

Potato Leaf usually has fewer cuts or serrations on the leaf edge. Sometimes there are a few large notches in the mostly smooth leaf edge.

What's the difference between "indeterminate" and "determinate" tomatoes?

Determinate tomatoes, or "bush" tomatoes, are varieties that grow to a compact height (generally 3 - 4'). Determinates stop growing when fruit sets on the top bud. All the tomatoes from the plant ripen at approximately the same time (usually over period of 1- 2 weeks). They require a limited amount of staking for support and are perfectly suited for container planting.

Indeterminate tomatoes will grow and produce fruit until killed by frost. They can reach heights of up to 12 feet although 6 feet is normal. Indeterminates will bloom, set new fruit and ripen fruit all at the same time throughout the season. They require substantial staking for support.

Should I prune or not prune tomato suckers?

Never prune a 'determinate' type tomato. You want all the fruit you can get from these shorter plants. Indeterminate varieties vary in their response to pruning, some reportedly have increased yields when the young plant is pruned back to three or four vines. I prefer to let the plant produce stems for better fruit production and better leaf canopy to protect the fruit from sunscald. However, I like to remove most of the suckers at the bottom 10" of the plant to invite greater air flow at the base of the plants and reduce the risk that fruit will touch the ground where they insects and disease might be encouraged. Know that removing new flowers near the end of the growing season can help speed up the ripening of mature fruit.

Is pruning necessary at all?

Pruning is not necessary at all. However, if you want taller plants or huge fruits you will need to prune excess vines that start to form where the leaf meets the main stem.

It turns out that different tomato cultivars vary in their response to sucker removal. For some, light pruning (removing the first four suckers) results in the greatest yield; for others, no pruning gives the highest yield. Experiment with your favorite variety.

What is the best spacing for my tomato plants?

Indeterminate Heirloom tomato plants can get really big (generally 7' tall and 4' wide). If you are planting the same variety in a row, I suggest spacing your plants 3' apart. If you are using a circular wire trellis I suggest 4'-5' apart. Determinate plants can be planted 2' apart. You'll want to separate different varieties by at least 8'.

What's the difference between a regular tomato and an heirloom tomato?

For the past 40 years or so, when most people spoke of "regular" tomatoes they meant hybrid tomatoes because these were the most commonly available in markets and seed catalogues. Hybrid tomatoes are genetically created for a particular purpose the marketing and distribution interests (i.e., thick skins so they can withstand the weight of huge amounts of tomatoes stacked in a truck, a longer shelf-life so they might last a week or longer at the market, or a particular disease resistance). Too often a hybrid's last priority has been taste. That said, there are some fine tasting hybrid tomatoes that have a loyal following. Like many gardeners, I only grew hybrid tomatoes BEFORE discovering the superior flavors of heirloom tomatoes. Heirloom tomatoes are open-pollinated tomatoes, whose seeds have been handed down from generation to generation. They are generally thin-skinned, extremely flavorful and have a natural resistance to disease.

Can I save the seeds from hybrid tomatoes?

Yes. However, you will not get a tomato like the parent. If you want to have fruit that is identical to the fruit you are seeding, you need to do so from an open-pollinated or heirloom tomato. One of the primary reasons that heirloom tomatoes are so popular is because after finding a favorite heirloom tomato variety, you can save the seeds of that variety for many generations to come.

Why are heirloom tomatoes so 'ugly'?

Beauty is in the eyes of the beholder. When I hear this comment it generally comes from someone who has only experienced the classic red, round, clear-skinned tomato. Heirloom tomatoes come in many 'strange' shapes, colors and sizes. They can also have markings that some might consider less-than-perfect or unattractive (cat-facing, concentric cracking, zipper or stitching lines, green shoulders) or deep folds or fluting. I like to point out to heirloom tomato novices that the wonderful diversity of physical features possible in the many varieties of heirloom tomatoes, are, like in people, a blessing. In fact, many of the colors and shapes of some heirloom tomatoes are more reminiscent of jewels. And behind the face of these wonderful diverse looking heirlooms, is the TASTE that will forever change how you think of a tomato.

What can I do to get my kids to like tomatoes?

Introduce them a tomato that has something to be excited about in the taste. Most kids have never tasted a tomato with taste. I would start them out with some of the sweeter cherry tomatoes. (Snow White, Isis Candy Cherry, Blondkopfchen, Camp Joy, Black Cherry, Yellow Pear) Offer them several kinds so they can distinguish the flavor differences and select favorites. Try have them grow their own tomatoes and appreciate some of their own harvest.

What does "days to maturity" mean?

This is the number of days from transplanting your seedlings in the garden until the first appearance of mature fruit. With all of my all my tomato descriptions on tomatofest.com I have ("Days 65")

Is the tomato a fruit or a vegetable?

Generally I respond to this question with, "What do you think it is? And regardless of what they answer I say, "You're right." It's a fruit, botanically speaking because it develops from a botanical ovary that contains the egg cells. According to the government, it's classified as a vegetable so it can be taxed for additional revenues. If you have a bet going with a friend, say "it's a fruit" to win.

What kind of tomatoes are best for canning?

Tomatoes with flavor. Although medium-sized, higher acid, red tomatoes have most often been used for canning, any colored tomato is suitable if sufficient acid (citric acid or lemon juice) is added to make up for the sweeter (low-acid) varieties. I love to chop a selection of different colored tomatoes or select a blend of yellow varieties or can variety-specific tomatoes.

What tomatoes best for container planting?

I used to grow almost all my tomatoes in containers around the house. You really can grow any variety in a container as long as the container is large enough for adequate nourishment, water, root growth and is available to sunlight. The larger your planter is the better. Staking opportunities for your plants in containers are limited especially if your planter surface is a solid patio. Under these circumstances, I've used stakes into the planter soil and where possible I tie the stems from above (roof eve, patio above if you are in an apartment, etc.) Planting determinate and semi-determinate tomato varieties offer less of a challenge since they don't need much, if any, staking. See my determinate varieties. Generally, medium to smaller fruited varieties are better suited to container planting. Most important is to make sure your containers have a good amount of sunlight.

To mulch or not to mulch my tomato plants?

I believe in mulching. The benefits have been proven. Warms the soil, holds moisture in soil and keeps back weeds. I prefer plastic mulch (regardless of whether clear, black or red) to organic mulch.