You should only plant up to seed leaves when potting on tomatoes, or most plants, for that matter.
However, tomatoes can put out extra roots from the stem, so other folk may well tell you that you'll be OK.
John Reynolds wrote (see)
Does it hurt to cover baby leaves when planting tomatoes
You don't cover them but pinch them off before planting.
The rule of thumb with toms is to plant deeply. All of the plant's stem that is buried will turn into root structure. By planting out time, the first true leaves will be forming a canopy, and second and even third sets of leaves will have developed (or be developing) on mini-branches beneath them.
Nip off the cotyledons - if they haven't already fallen off - then also nip off any other mini-branches carrying second and even third sets of leaves, leaving only the canopy of first true leaves. Then plant deeply, right down to the canopy, so only the canopy is showing above the soil. Don't worry about losing the second and even third sets of leaves. The buried bare stem will quickily become root structure and the plant will grow like the clappers.
I have just pulled up the last of my tomato plants, heavy with fruit but again, for the third year running, plagued with blight. It is so depressing. Before all this I grew wonderful tomatoes each year which yielded so much fruit that I had to preserve them in olive oil for the winter. I don't know what I am doing wrong. This year I tried them in a greenhouse for the first time but the same thing happened again. I grow them in growbags so it is not to do with using infected pots. Does anyone have any suggestions?
If the problem was fungal, it had nothing to do with infected pots. Some bacterial and viral diseases can be transferred via previously infected soil and pots.
Can you post a photo? It would be interesting to see what the problem actually was.
Fungal disease is the most common ailment in the home tomato garden. You can't avoid fungal spores. They're airborne, invisible to the naked eye, and they're everywhere. Unless you spray preventively, there's nothing much you can do except undertake some basic housekeeping drills to try to minimise their impact.
Avoid wetting any foliage. Damp foliage is heaven for a fungal spore. Still air and clumps of foliage fall into the same category. Try to maximise air circulation by (1) keeping individual plants at least a metre apart, in fact as far apart as your growing space allows; (2) judiciously trimming foliage on individual plants to avoid walls of clumps of leaves; (3) remove the lowest branches of individual plants to maintain a gap of at least a foot between the lowest foilage and the soil. Fungal spores can and will fall from the leaves to the soil underneath and can splash back up again when watering. The gap between the lowest foliage and the soil helps against this.
In fact, you probably have more chance of dealing with disease outdoors than in a greenhouse. You need very very good ventilation to overcome the fact that the closed environment can be an incubator for disease.
Are they "black holes" or sunken black patches at the blossom end? On the bottom of the tomato? If so, it's probably Blossom End Rot. Here's what it typically looks like:
The plum-type varieties like Roma are extremely susceptible to it. No one knows why. I've had Roma plants plagued by BER growing right alongside beefsteak varieties - identical soil, identical watering, etc - that haven't shown the slightest sign of BER.
If that's not what you've got, can you post a photo?
Whether you've got a fungal or bacterial problem, spraying now isn't going to help the already-infected foliage. If you have unaffected foliage, spraying will help against infection. That Bayer product seems to be copper-based, one of the traditional anti-fungal ingredients. Spraying doesn't kill the spores. Effectively you're coating the leaves to put a barrier between the spores and the leaf surface, stopping the spores getting a grip. So you have to spray every leaf and on both sides. Spray about once a week, re-spraying if it rains.
As I said, Romas can present their own challenges, but I wouldn't give up on the plants by any means. They sound like they're in pretty good shape despite the problems and worth fighting for.
Am pretty sure it's not blossom end rot - these spots are generally on the sides of the fruit for starters. Not the best photo but hopefully this gives you an idea.
Thanks for your advice!
No, definitely not BER. The photo isn't terribly clear but you've probably had insect visitors. Have a good look around the foliage - both sides - at night with a torch.
ok, here's a photo that shows it better i think. you can see the big fruit towards the bottom right has one of these sunken spots on it, white in the middle but with a raised black border.
i described it as a 'hole' but it doesn't look as if anything's gone in it! but maybe it has...
most of the fruits on the romas have got at least one of these spots on, some have got several where they're smaller but the spots look more speckly.
you might be able to see that some of the leaves have got holes in, look quite 'papery,' and/or have yellow/brown patches too. i've cut away most branches which have been badly affected though.