Determinate height.

[Doug9345]

While I've grown a few determinate tomatoes I've never paid much attention to them.

I know that the vine finally ends in a flower. What I've never paid attention too is how many trusses before that happens, why that number instead of more or less? Is it variety dependent thus purely genetic or does weather play a part?

After it produced fruit if I pruned the plant back to the lowest leaves would it start growing again and produce another crop?

[travis]

The terminated height, or extent of growth, for determinate tomato plants is variety dependent to a large extent. Your choice of fertilizers, placement with regard to available sunlight, time of year, etc., also are determining factors. Whether the variety is fully determinate or semi-determinate also is a factor.

Efflorescence to internode spacing also is variety dependent.

Yes, determinates will grow back from severe pruning as with indeterminate vines, but you will severely affect the fruit production by pruning or cutting back a determinate bush.

[bower]

I grew quite a few determinate varieties this year, and as Travis said, the height varies depending on the variety, and the number of trusses too. The number of trusses seems to be dependant on how vigorously the plant produces suckers. So for example, Zolotoe Serdtse continually produced new suckers, each with several small clusters of flowers and a terminal cluster. Compare Danko, which hardly suckered at all, but produced very large clusters of flowers and fruit. Danko only grew and ripened some of the fruit set as the main crop, but after harvest it grew some more of those little ones as well as setting some new ones. I think a more productive variety could be produced by crossing Danko with a bushier, more vigorously suckering type. Really short varieties like Cold Set, Siletz and Beaverlodge Plum have a production limit because of their size too - they only have enough leaf to nourish so many fruit.

All of the determinates I've grown have produced new shoots and flowers after they finished ripening their crop and were cut back. The season is too short by that time to find out whether they would produce a full size plant and a second crop, but given enough nutrients and a long season, I don't see why not.

[Cole_Robbie]

I grew almost exclusively determinates in my high tunnel last spring, and I agree that it varies a lot by variety. I grew some Northern Delight, which is a hybrid saladette from Territorial, and they yielded heavily, but when they were done, that was it. The plant would live, but not set any more fruit.

[newatthiskat]

I am planing on growing several types of tomatoes next year that are determinate. I can think of only one type I have grown in the past. It will be a learning experience for me for sure!

[matilda'skid]

Will someone explain Siberian. Tania describes it as determinate. I am afraid I don't pay close enough attention to the growth habit or know how to describe it. Siberian is pretty early and has lots of 1 by 2 inch oval tomatoes all summer. I just had a frost and picked Siberian fruit last week.

[dfollett]

Same question here about Siberian. I picked the first ripe tomato on June 17 and it was still producing when frost stopped it in late September. It never did get much over 3 feet in height, but was extremely bushy and full (in an Earthtainer with an Early Girl that exceeded 6 feet).

[Tania]

More than half of determinate varieties produce all season long in our garden, because we do not have a long season.

To me, a determinate variety is the one with branches that eventually terminate with flower cluster. Some will continue to produce lots of suckers that would flower and fruit, and this can explain why it keeps producing over longer period.

In a bad year when we only have 50 days of warm summer days, it may be difficult for me to tell some det. and compact indet. varieties apart, because some det. varieties will not have enough time to produce terminal clusters.

Tatiana

[travis]

Determinates and semi-determinates can be identified from indeterminates by counting the internodes between efflorescences.

Once a determinate or semi-determinate begins flowering, on either the main stem or side shoots, it will continue to produce flowers on every internode or every other internode until the stem or side shoot terminates in a single flower cluster.

That last, terminate flower cluster will appear just past the preceding cluster. Let me see if I can find a photo of this characteristic, and I will post it at the end of this message.

Indeterminates, on the other hand, once they begin producing flowers on the main stem, will only produce subsequent flower clusters in every third internode. Same goes for indeterminate side shoots ... they begin producing flowers about the 5th to 7th internode, then only on every third internode.

Here is a photo of a terminal flower cluster (efflorescence) that emerges on the leaf pediole just past the preceding efflorescence on the last internode. The terminal flower emerges exactly where the next stem segment should emerge to form an ascending internode, but in the case of a determinate, the flower cluster terminates the forward growth of this stem.



Here is another example of a terminal flower cluster emerging from a leaf pediole just past where the preceding efflorescence is producing new fruit on the preceding internode.




Here, I hope, is a photo showing the more frequent internode spacings of a determinate variety.



This is not as clear an image as I would like it to be, but you can see the lower efflorescence on one stem, followed by a terminal flower on the leaf pediole just above the node. Then below that, you can see a side shoot emerging from the node just below the lower flower cluster, and that side shoot begins at once producing a series of efflorescences in every internode.

This is why determinates produce so much more fruit within a shorter period of time on more compact plants.

Below is another example of more compact flowering, with flowers, leaf node, then next flowers right on the next internode. Indeterminate varieties don't do this. Rather they only produce flowers every third internode, and the side shoots on an indeterminate don't immediately start setting efflorescences until they've produced 4 or so internodes, while determinates will produce efflorescences immediately in the first or second internode on all side shoots.

[tlintx]

So... two questions. If I have a determinate plant that hasn't flowered or set fruit yet, even though it's reached full size, is it likely to flower and set fruit if conditions improve? Or is there a limit -- it's grown "this" many branches, none of them set fruit, so it is done?

Second, if I take a cutting from a determinate that is on the way out and root it, does it start over as if it were a new plant, or continue from whatever point I took the cutting? I would assume (or maybe I read it here!) the second? So there'd be no point in taking a cutting from a determinate that is already done fruiting?

I realize it might not be a cut and dried thing -- just trying to determine what I should cull, what I should leave out, and what I should bring inside!

[Salsacharley]

This is good info. I appreciate the explanations from Travis with the photos. Now I won't be so confused when I see these different behaviors.

I look forward to an answer to the questions tlintx posted above, too.

Thanks,

Charley

[Doug9345]

Thanks for the nice pictures. I still have the question of why let's say a determinate flowers at the forth internode, continues until the tenth and then terminates in a flower cluster. Why not the first or twenty-first. The second part of the question can that number be manipulated either through breeding or growing conditions?

[NarnianGarden]

So the question that came to my mind - similar to tlintx' - is this: can cuttings from determinate varieties be rooted and planted to produce new plants? That seems to be an easy way to get new and fruitful plants with indet tomatoes - I still have several 'little suckers' from Black krim growing on my window, and they're heavy with decent sized fruits!

[travis]

Originally Posted by Doug9345

I still have the question of why let's say a determinate flowers at the (fourth) internode, continues until the tenth and then terminates in a flower cluster. Why not the first or twenty-first.

Doug, yes, a determinate typically starts flowering in the fourth or fifth internode just as do indeterminates.

As to how many efflorescences a determinate produces on the main stem or each of the side shoots, I cannot say for sure that it's ten. Maybe so, but I never counted.

Or maybe so on the main stem, but I don't think it's always 10 on each side shoot. Seems fewer than 10 on the side shoots best I can remember. I know it was less than 10 on the main stem of Mozark, and definitely less than ten on each of Mozark's side shoots. Mozark is a fully determinate variety that only got 2.5 to 3 feet tall for me, and produced usually 40 or so tomatoes in clusters of maybe 3 or 4 tomatoes each, and aside from the main stem had maybe 4 or 5 side shoots, so by that county I definitely can say none of those shoots or the main stem had 10 flower clusters.

Anyway, I don't think it's a universal set number. I think it may vary from variety to variety. I'll make sure and pay closer attention next summer, and take a definite count by variety.

Originally Posted by Doug9345

The second part of the question can that number be manipulated either through breeding or growing conditions?

Yes, I think you can manipulate the number of efflorescences that a determinate tomato plant will produce through your breeding efforts.

Again, using Mozark as the example, I crossed it with Sioux, supposedly an indeterminate variety.

Over the past several years, I've been growing out filial generations from that cross, and have gotten a full range of growth types from fully indeterminates to fully determinates.

Some of the determinates are nearly identical to Mozark, producing 40 baseball size tomatoes, then terminating completely.

One line I am particularly fond of is what I call semi-determinate, in that it does finally terminate, but depending on when you plant it, it's likely to produce until frost.

What I like about this particular semi determinate line is that it will set a flower cluster in an internode spacing, then skip the next internode, and set the flower cluster right opposite the leaf node, then skip that internode and set the next cluster in the middle of the following internode.

That may seem like it's less productive than its fully determinate sister line, but the reason I prefer it is that it spaces the tomatoes out just a bit farther in time, always sets 3 or 4 tomatoes per cluster, and continues to produce over a long period of time which makes it the perfect fresh kitchen tomato for me. It's very similar to Celebrity, which itself is the standard for semi determinates, but is not quite as large, is much less hard, and just tastes a lot better.

NarninaGarden, I cannot answer your question because I have never cloned a determinate tomato plant.

I have read that cloning can reduce the overall production from clones, and reduce the lifespan of the clones when taken from determinate plants. But I have no anecdotal evidence of that claim.

[Doug9345]

Thanks Travis for your nice explanation. I always shied away from determinates because I didn't want the concentrated set and I'm just getting more interested in them.