Ever been seed shopping for your Summer tomato seeds and been befuddled by the term Indeterminate Variety? Then look on the very next seed package and see the exact opposite, Determinate? What does that even mean?, you ask yourself. Well friends let me try to shed some light on this murky subject and hopefully I will have you seed shopping like a pro when I'm done!
What Does It all Mean?
First off let's define the meanings of determinate and indeterminate.
Determinate tomato varieties are a type of tomato plant characterized by a low growing, bushy growth habit. These types of tomatoes will usually have a large flush of blooms all at once and produce tomatoes that ripen together within a short time span, usually two to three weeks. Most determinate varieties don't grow taller that about 4 feet and require caging to support the large amount of tomatoes it will produce. After that the plant is done producing tomatoes and will usually die off after the crop has been harvested. Many determinate varieties have the term "bush" in their name (Bush Goliath, Better Bush) but some may not (Roma, Celebrity).
Indeterminate varieties are "vining type" tomatoes, the will usually have a taller growth habit with a central leader. These types need to be tied or trellised to keep them manageable. They will also have fruit along the central leader at a steady interval, and make fruit until the frost, or in our case when it gets to hot in the greenhouse. Indeterminate types should be pruned by pinching suckers that grow at the leaf nodes to keep the vine manageable. Otherwise you will end up with a giant mess, don't ask me how I know!
So there you have it, clear as mud right, well let's get some visual aids going.
Determinate Variety: Roma
We started some Roma tomatoes this year due to demand mostly, this is our first year so your seeing them as new just like I am.
So here is our row of Romas, you'll notice the lower compact growth. We do have these on strings simply because we don't have any cages to use. Another thing to note is all the blooms, Like I said, they set all the flowers within a week, so we are looking at the final stage of flowering, after these are pollinated we should have a load of tomatoes. After these tomatoes are picked, this plant will be done with it's cycle.
In this view you can see how the flowers are spread all over the plant. You can see that terminal end of the plant has made only flowers and not any new growth, this signals that the plant has push out all it's blooms and is ready to pollinate.
Here is a better view of the terminal end, at this point the plant is around three feet tall.
Indeterminate Variety: Geronimo
This is our greenhouse mainstay variety, they are fast growing and produce well. Indeterminates are well suited for a greenhouse since they will produce over a longer period.
This is a view down the row of the Geronimo plants, you can see that they much more top growth oriented. These plants stand close to 4 feet tall and where planted about a week after the Romas. You can see the central vine growing with several clips holding it to the string, the central leader is where the tomato blooms are located on this type.
Here is a close up of the Geronimo, the blooms are closer to the leader and are at a set interval, with two leaves in between flowers. You can also see in this shot where a sucker has been pinched off on the left side, and directly below it to the right a sucker that has not been pinched. These will keep growing like this all season until the temps ramp back up next summer.
Which Type Is Better?
Well that depends on your needs I guess, do you want to have a long season of tomatoes with a few every week, or do you want to can some tomatoes and need a bunch all at once? We generally go with indeterminate type tomatoes for the simple fact that we sell at farmer's markets and need tomatoes every week. We always get asked if we grow Roma Tomatoes so this year we did. I guess we will see if they are worth it.
I would say for the home gardener, why not try a few of each. You can never have to many tomatoes...can you?
Well I hope that has cleared things up just a little bit for you. Next time your seed shopping you can go in a little better informed.
Thanks for explaining determination and in-termination of tomatoes.
Determinate tomatoes grow like a bush. Indeterminate tomatoes are viney meaning they grow almost exclusively from the tip if suckers are trimmed off. Because of this, trimming the growing tip of an indeterminate can severely reduce yields because it trims off the part where blossoms and fruit are produced. If the tip of an indeterminate is trimmed the suckers should be left to grow to form new tips capable of producing blossoms and fruit but it will take a lot longer. Ideally an indeterminate should just be staked and allowed to grow with only side shoots trimmed off. I mention this only because most articles fail to mention specifically not to trim the tops of indeterminates.
Very true, I have accidentally broken off many a growing tip. That'w when you hope yo didn't pinch back all the suckers.
Interesting. Good in depth info.
Thanks, I try!
I'm voting you up because I seriously have never heard of a more random thing to write about. I love it. I never knew there was such a thing as either kind of tomato. Now I know. Thanks for sharing.
I'm glad I could bring you some random knowledge!
Really interesting article and amazing pictures of the big tomatoe plants!