What causes Tomato plants to drop their leaves?

[Leeds_lad]

Not having a serious problem with it yet (could get worse though) but several of my tomato plants seem to be dropping a couple of their leaves every so often. This seems to happen more on a variety called Blue OSU

[taff]

It's april, it's cold, they don't like it ......zazen would know more about the blue ones.....

[Creemteez]

hi Leeds Lad,
How big are your plants? As they grow and mature, the lower leaves will naturally die off, but this doesn't usually happen until the plant is quite big. If they are still tiny, is it the very first seed leaves that sprouted? If so, this is quite normal and nothing to worry about - once they get a couple of sets of "true" leaves, they don't need the seed leaves any more - a bit like the initial boosters on a rocket, they're ejected by the plant.
If, however, it's proper leaves that are suddenly dropping off, it indicates a problem....Don't know what though... Do the leaves change colour before falling off? Do the plants otherwise look healthy?
Hard to suggest anything without further info. A picture may help....

[Leeds_lad]

They are about 10-20cm high and are kept in a heated conservatory so the cold shouldn't really affect them. As i said it's not worrying me that much, yet =p

[taff]

is it heated during the night too? it is humid or dry in there?

[Leeds_lad]

Yeah it's heated in there during the night as well. Would a lack of ventilation be a factor? many of it's windows are never opened and the door only for a short while.

[zazen999]

Pot size, running out of nutrients, too much or too little water - off the top of my head.

[taff]

^ see how she did that? Like she's been doing it for years


I doubt ventilation has anything to do with it, only whether it's dry/hot and drying the pots out quicker.

[Chef_uk]

Too little water would be my guess. drop the pots in to something bigger and fill 3/4 full. If the pots float, they have dried out and will love soaking up a lot of the water. Hold down in place to help the pressure gently force the water in, should only need a couple of seconds to hold down. Then leave until no more water is soaking up (gauge by the appearing waterline on the outside of the pots as the water drains down).

[rustylady]

Too little water would be my guess. drop the pots in to something bigger and fill 3/4 full. If the pots float, they have dried out and will love soaking up a lot of the water. Hold down in place to help the pressure gently force the water in, should only need a couple of seconds to hold down. Then leave until no more water is soaking up (gauge by the appearing waterline on the outside of the pots as the water drains down).

You shouldn't need to hold the pots down. Better to put an inch or so of water in a wide container and stand the pots in that and leave them to soak up what they need. Obviously you need to determine first whether they actually need water, and this is best done by feeling the weight of them.

[Leeds_lad]

The watering on them is fine as well. They get a good amount of water every other day. Might be their pots then I guess, time to get them into another

[Creemteez]

Check the bottom of the pot - if the roots are coming through the drainage holes, it's time to move up.

[Leeds_lad]

Nope, none of that. Strange really. As i said it's pretty much only this variety doing it, they are near other varieties that are healthy as 'eck and twice as big. Same conditions and everything.

[Sylvan]

Quite a few of my tomatoes are dropping leaves this year too. It's worrying.
The leaves are going really floppy first. It's almost like damping off, but just the lower leaves rather than the whole plant.

[Leeds_lad]

It seems to be still doing it, even with a good watering. Just had a few where the leave and stems looked healthy as they could be, lush and green, but simply broke off.
I'll get some pictures up. As i said it mainly happens in my Blue OSU variety but also in Purple Cherokee from time to time.