Should I prune Roma tomatoes?

[Yasminh14]

I have 9 Roma VF tomato plants, and am unsure whether I should prune them. Googling tells me that Romas are determinate, so I just left them to do their own thing. However on the packet it says semi-determinate, which seems to be neither one thing nor the other, so what does this mean in terms of pruning and how tall they will grow?

I have them in 2 rows, 5 at the back and 4 staggered across the front. I thought I'd left plenty of space between them, but the plants are now so bushy that those at the back are not getting much sunlight and I'm concerned that the fruit won't ripen properly, and that they might end up with too many trusses for the plants to cope with if I don't prune them somehow. They are now around 4ft tall and still growing like crazy, sending out new shoots with flowers all over the place. I'm just not sure of the best way to manage them.

[brownfingers]

I didn't realise they were determinate until I found out on here. I had already removed quite a lot of sideshoots. They are still producing so many trusses I don't know how I shall support them, or how the plant is going to feed them. I'm pleased that I removed some. They even throw sideshoots from sideshoots!

[teakdesk]

so what does this mean in terms of pruning and how tall they will grow?
...
those at the back are not getting much sunlight and I'm concerned that the fruit won't ripen properly

I find it depends on the growing conditions as to how tall... they CAN stop at around 4 feet tall but in darker conditions (like mine) tend to grow taller. You need to provide support for many side-shoots not just the central vine and remove as few as possible side-shoots.


Don't worry about getting sunlight to all the fruit; they will ripen tucked away behind but you must maintain ventilation or risk botrytis and other diseases.


The main difference, for me, between indeterminate and determinate is that determinate will produce ALL its fruit in one flush over just a couple of weeks, whereas indeterminate will keep producing over the season. If you can keep a Roma healthy after its picking flush you can get some later tomatoes so don't keep too quick to clear out.

Roma are a great tomato for sauces and their ability to produce a lot of fruit together helps in production and freezing of passata and similar sauces.

[Richard Eldritch]

I have Folia F1 which are close. I've only allowed them to grow a 2-3 trusses and and pinched out all sides and top shoots to try and get a crop before blight. ( I'm also spraying with asparin as a test)

[brownfingers]

Mine have stopped at about 2 1/2 ft tall, but more sideshoots than you can shake a stick at. I reckon I need to remove some to make the plants more manageable and possibly put more energy into the remaining fruits.

[Yasminh14]

The main difference, for me, between indeterminate and determinate is that determinate will produce ALL its fruit in one flush over just a couple of weeks, whereas indeterminate will keep producing over the season. If you can keep a Roma healthy after its picking flush you can get some later tomatoes so don't keep too quick to clear out.

The problem is that the packet describes these as "semi-determinate", whatever that means! The plants I've got are definitely not producing all their fruit in one flush, as the first flowers appeared when the plant were only a few inches tall (several weeks ago), and those fruit are already getting to a good size, while new flowers are appearing constantly further up and around the plant.

I've got to be honest, I'm not entirely convinced that these are in fact Roma tomatoes. They were Thompson and Morgan seeds, but not only are they not producing the fruit in one flush as I'd expected, but the fruit are not at all plum shaped. They are your regular round tomatoes. In which case, if they are not Roma, they could be anything and I could have been caring for them completely incorrectly! Wondering if I should just pinch out a load of side shoots, retain the fruit that's already developing and treat them like normal vine tomatoes? What do you all think?

[brownfingers]

I've decided just to leave mine to it. If they get too big to support themselves then tough. I should still get enough toms for my needs off them. Any plums I grow next year will be cordons.

[teakdesk]

The problem is that the packet describes these as "semi-determinate", whatever that means! The plants I've got are definitely not producing all their fruit in one flush, as the first flowers appeared when the plant were only a few inches tall (several weeks ago), and those fruit are already getting to a good size, while new flowers are appearing constantly further up and around the plant.

A true Roma tomato is determinate in that the plant will grow to around 4 feet tall when the growing vine tip will change into a flower truss. There will have been other flower trusses coming off the vine earlier as the plant grows but after the growing tip turns into a flower truss that vine will not produce any more flower trusses.

So each vine on the plant will produce about 3 or 4 flower trusses before stopping. These all ripen in their own time but since they are normally produced over a period of not many weeks they also crop over not many weeks. Thus we say they produce in one flush even though this flush may be over a few weeks.

An indeterminate plant does not change the growing tip into a flower truss and will continue to produce flower trusses all season long (and even next season if kept alive). Thus the cropping period is over months rather than just a few weeks.


Thomson and Morgan have 'specially bred' a variant of Roma, that they continue to call Roma, and this plant is described as semi-determinate.
Here each vine will produce 3 or 4 flower trusses and then change the tip into a flower truss and produce no more - just like the true determinate - but after that any of the side shoots that the plant puts out can be used as the growing vine.
Each side shoot will also produce 3 or 4 trusses and then stop but then another side shoot takes over.
The plant continues to put out side shoots over the season so cropping can take place over the whole season.



Hope that is clear?????

[Yasminh14]

Thanks teakdesk, yes that is clear I think! I think I am still going to have to prune them to some degree though, as they are just taking over the bed that they're in at the moment and the pepper and chilli plants that are with them are getting swamped just as they're starting to flower. There isn't any more space to put in loads more canes to support the dozens of side shoots, they are growing into a jungle, I've never seen tomatoes like these!!

I think next year I will stick with cordon varieties, you know where you are with those . My cordon cherry tomatoes look lovely and well under control next to these triffids.

[BertieFox]

In my opinion Roma is a very poor sauce tomato compared to many of the great hybrid varieties now on sale. Most of these ARE indeterminate so you can treat them just like any other tomato. I have grown a few Roma this year but found them so far very unproductive, and even more susceptible to blight than the others (most affected this year). For future years I would really recommend you try something like Super Marzano, which has a really large, juicy 'Roma' type fruit. Only problem seemed to be a tendency to blossom end rot if watered irregularly, but good flavour.

[Yasminh14]

Thanks BertieFox, I did actually want to try San Marzano, but on the particular day I bought the seeds the shop didn't have them, and I thought (mistakenly it seems) that Roma would be just as good. Ah well, you live and learn! At least they seem to be fruiting OK and blight free so far, I'll just have to see what they turn out like. Have pruned out a number of side shoots now that hadn't yet set fruit, they look a bit better, but yes I will try another variety next year.