What's the lowest temperature toms can stand?

[Sylvan]

I read somewhere that if tomatoes are exposed to temperatures below 10C they sulk and don't start growing again for ages.

Mine tend to get left out too long and they do cope with temperatures lower than that (but maybe they would have done better if they had been cosseted more?), but this year I'm growing some that are probably more delicate than Tamina and good old Gardener's Delight, so I thought I'd better do it properly.

They've been out at 9C, but today it's only 6 so they're inside.

What's the lowest temperature I should subject them to?

[Flummery]

I've not started putting mine out yet - and when I do, I bring them in at night until I'm sure there won't be a frost - so a long time then!
If it gets anywhere near frost - down to 3 or 4 - you are likely to get damage.

[Sylvan]

I wouldn't dare leave them out at night but I thought they might enjoy going out to play in the sun and fresh air for a couple of hours a day, instead of sitting on the worktop, leaning hungrily towards the light.

I wouldn't put them out at 5 or 6C but I was wondering where the cut off point is, before they start to slow down.

[Flummery]

They do say that they don't actively grow below 10C.

[Snadger]

As they are a close relative to spuds and the foliage looks just he same, I would say any sniff of cold............and they are gone!

[Aberdeenplotter]

The trick with all vegetables is to get them growing and to keep them growing. Most plants react badly to a check and it is best to maintain the same growing conditions throughout. 55F/ 13c is about the minimum needed for sustained growth

[Sylvan]

55f/13c *choke*
What are the chances of temperatures that high before late May?

That ties in with the info I came across t'other day that they won't set fruit until they have had at least two nights at 55f.

Well, they were out at 9c yesterday (I'm trying to teach myself to think in new money ) and 10 the day before, but I won't subject them to that again - poor babies.

Thanks you'all.

[King Carrot]

If you've got tomatoes in the past doing it the way you did, why change anything, you can grow always some new varieties as well. In a Bob Flowerdew book I read, I remember him comparing his straggly sick looking tomatoes that were covered in ripening fruit with those of one of his neighbour’s tomatoes, that were superb examples of a strong stemmed, very healthy and leafy tall vine covered in green fruit (you get the idea!).

A couple of things that I think can help are to save the seed from plants that grow and crop well in your conditions as the seed will be acclimatised and use a seaweed feed as per instructions (half strength until 4 inches tall) as it's got a kind of plant antifreeze in it.(don’t take this literally though –it helps a bit)

I try and keep my toms above 5C once they're planted in a cold greenhouse and I'm sure they've survived slightly lower temps than that as I’ve never felt the need to use heat in a couple of years – if you’ve got them outside you need to take any wind chill into account. Tomatoes will also slow up if they don’t get enough light as well so it’s swings and roundabouts.

[Sylvan]

I was happy with the tomatoes I grew before, but I hadn't expected much from them, considering our less than optimal conditions. I thought perhaps if I'd treated them a little better we might have had better results.

Perhaps I should "treat 'em mean, keep 'em keen" with the bog standard ones but cosset the more unusual ones a little more (since I have so few of them).

I hadn't realised the seaweed extract was helping them cope with the cold.
Haven't used any so far this year, but it's sitting under the sink waiting for its time to come.

[Aberdeenplotter]

.

(I'm trying to teach myself to think in new money )

Thinking is too hard. Try this convenient website. Celcius and Fahrenheit Converter

[Sylvan]

Oh it's alright Aberdeenplotter. Metrication happened just as I was changing to "big school" so we used SI units for science and imperial for domestic science and I've been using "9C/5+32" for the last 40 years. I have to convert the weather forecasts in my head because I automatically think in Fahrenheit.
(Have to convert metres to feet and inches and hectares to acres as well - actually even my teenagers think in feet and inches/stones, pounds and ounces mea culpa...)

Thanks for the thought though. (It's the thought that counts... Boom boom )

[Shadylane]

55f/13c *choke*
What are the chances of temperatures that high before late May?

That ties in with the info I came across t'other day that they won't set fruit until they have had at least two nights at 55f.

Well, they were out at 9c yesterday (I'm trying to teach myself to think in new money ) and 10 the day before, but I won't subject them to that again - poor babies.

Thanks you'all.

Ours were in and out every day right up until mid/late May. It was a major PITA last year cause of the extra late frosts. You don't have to coddle them all and I think this year we may leave half out to brave cooler temps and bring some in at night for an early crop.

[Two_Sheds]

Bob Flowerdew ... his straggly sick looking tomatoes that were covered in ripening fruit

But that had nothing to do with the cold
He had basically starved them, made them think they were dying so they fruited more quickly

[Two_Sheds]

I try and keep my toms above 5C once they're planted in a cold greenhouse and I'm sure they've survived slightly lower temps

How much fruit do you usually get? I've never weighed mine, but I don't think I get a lot of fruit (unheated gh, toms put in early May).

There is considerable evidence that night temperature is the critical factor in setting tomato fruit, the optimal range being 59° to 68°F [15c - 20c]. With night temperatures much below or above this critical range, fruiting is reduced or absent. Low temperatures reduce the production and viability of pollen. source: doh, lost it

[Flummery]

I don't actually let my own stay outside until late May. Then I plant them in the greenhouse border. They won't go out in the day to the cold greenhouse till it's a bit warmer. I don't like to check their growth, as Aberdeenplotter says. It does mean a lot of back and forth morning and evening though!