Tomato Seedlings min. temperature requirement

[falkon]

I have around 70 tomato seedlings on my windowsill which desperately needs to be re-potted. but 70 pots cannot fit on my window.. how low temperature tomato seedlings can tolerate
Thanks in advance

[OllieMartin]

I've just moved my seedlings out into my plastic greenhouse, it is probably as cold as the air outside, but without any windchill factor. They are surviving fine.
They are about 4-5cm tall at the moment.
Temperatures here are as low as 2°C at night.

[Nicos]

Do you have a cold frame you could put them in once potted on?
The wind chill is the killer- also they'd need at least a week of hardening off for them to get used to the lower out side temperatures.

70 plants eh? - you must love toms!!!

( Ollie- I'm really quite surprised that at 2C they're doing fine!- ya live and learn don't you???)

[OllieMartin]

( Ollie- I'm really quite surprised that at 2C they're doing fine!- ya live and learn don't you???)

TBH I'm only guessing at the temperature. I just looked on BBC weather to see what the minimum temperature has been in my area and assumed it will be the same inside the mini-GH.
The facts are: They're surviving in a mini greenhouse, outside, overnight.

[Flummery]

For active growth I think you're looking at a min of 10C.

[falkon]

hmm. yes.. i will repot them and put them in conservatory instead.. where the temperature stay 2-3 degree above from outside temperature during night.. but is very good during day time...
thanks...

@Nicos... I do have a cold frame but its surrouned by snow so far.... Actually last year I only had 3 tomato plants... this year I sowed 10 seeds of 6 to 7 different types and got 100 % germination that what i was not expecting... some seedlings will be given away once they are strong enough....

[Nicos]

this year I sowed 10 seeds of 6 to 7 different types and got 100 % germination that what i was not expecting....

That happens with me and lettuce- sometimes I get about 10 from 100 seeds ( hmm...and a munched slug route meandering about the pot!)

And other times all 100 succeed

[BlueHeather]

Reading this with interest as am in a similar position. I have about 25 tomato plants some a little more advanced that the others as yet and have had to move them into an unheated porch......... newly built and glass all around so plenty of light - but it is unheated......... do you think they will be Ok in there for a few weeks until I can get them into the greenhouse maybe 2nd wqeek April? Obviously it is draft and frost free just cold overnight....... any help appreciated as new to this and don't want to kill them all off...... sdly my other windowsill inside lounge and kitchen have new sprouting seedlings so just not got any more room.......

[veggiechicken]

I've had some tom seedlings in the GH for a few weeks. At night I cover them with a propagator lid and bubble wrap. They look a bit blue but they're surviving.
Can you keep a few in the house as insurance?

[Thelma Sanders]

They really don't like low temperatures - when I've had toms turn blue, they never seem to recover

Nowadays I just sow again, rather than waste time looking after them and hoping for the best.
Still plenty of time to start again.

[veggiechicken]

I have lots more indoors so I'm not too worried about the blue ones

[jackarmy]

Mine are all in the cold greenhouse.
Coldest temp they have had to endure so far is 0.8c, at night they are covered in several layers of fleece and they are all doing ok , we had a frost the other morning but the g/h lowest was 3.8c.
I keep an eye on the forecast and if it looks like it may be a hard frost i will contemplate bringing them in( still to make my candle heater lol).
Anyway, the cold may slow them up a bit but daytime temps in the g,h are always above ten ( atm) from about 9.30 untill 7pm maybe later, that combined with the improved lighting over a windowsill makes me take the chance.

[SusieG]

I have 2 trays of tom seedlings in unheated porch - they are doing ok. All others are jostling for space on various windowsills about the place - also looking healthy, healthier than the colder temp porch dwellers - thinking about potting on soon and putting into unheated GH

[lolie]

How many sets of leaves do they have? How big are the pots?

As mentioned, wind can be an issue because it will dry out the leaves. Popping small freezer bags over each pot helps maintain the humidity.

If the pots are small, you need to find a way to group them together to help them maintain soil temperature. Air temperature =/= soil temperature. Something as simple as popping them in a kitty litter tray with newspaper packed around each pot could help.

I have a small blowaway greenhouse and I find the temperature in that is always at least 4 C higher than the ambient temperature. If you've got anything transparent like that to keep in moisture and keep out wind, you can cover it of an evening to keep in the heat generated during the day.

As mentioned, your seedlings won't "take off" until it's a bit warmer, but they shouldn't need too much babysitting to survive cold nights if they're protected.

[anton002]

Mine are currently in my conservatory and seem to be doing fine ,although the underfloor heating is set on low which is probably helping