Follow up tomato question

[cabbagepatchkid]

With the new plot, I've inherited a polytunnel which has 2 raised beds in it. Approx 2m x 1m, and at least 60cm deep.

If I'm keeping my tomato seedlings in the polytunnel in their little pots (and they are thriving btw, thank you guys for that advice), and they are destined to go into these raised beds anyway, could I just put them into the beds now? Is there any reason to wait? They are quite big/strong seedlings, about 30-40cm tall.

[nickdub]

I've been planting my tomatoes in the poly-tunnel for about a week. I use bottomless pots which stand on the soil at the sides, mostly because that's the way I've done it before. Of course if the weather turns cold and frosty I shall look like a bit of an idiot, but I reckon the plants, which sound about the same size as yours, were getting too large to move inside anyway.

[katyhasclogs]

Are tomatoes ok outside but under cover now then?

I've been putting ours outside in the blowaway during the day since Sunday, and bringing them in at dusk, but I'd love to get them out there 24/7. The thermometer in there is registering the odd 4-5C at night (and up to 40C in the day, which I'm slightly skeptical about to to be honest).

[bramble]

If it were me I wouldn't leave them out overnight just yet.
Seems there is a cold spell coming over the weekend.
Also the difference in the very high temp in the day and the major drop at night won't help.

[nickdub]

Are tomatoes ok outside but under cover now then?

I've been putting ours outside in the blowaway during the day since Sunday, and bringing them in at dusk, but I'd love to get them out there 24/7. The thermometer in there is registering the odd 4-5C at night (and up to 40C in the day, which I'm slightly skeptical about to to be honest).

No sorry, too cold I'm afraid - toms won't put up with less than about 10 C for more than an hour or two.

[katyhasclogs]

That's good to know, thanks! I'll continue bringing them in for now and keep an eye on what the thermometer's doing.

[Chris11]

No sorry, too cold I'm afraid - toms won't put up with less than about 10 C for more than an hour or two.

Are you saying that established tomato plants will die if they get an hour or two at 9*C overnight?

Obviously the cooler and more prolonged the low temperatures, the more risks to your tomato plants slowing down, but I think they're a lot more hardy than you suggest.

[nickdub]

Are you saying that established tomato plants will die if they get an hour or two at 9*C overnight?

Obviously the cooler and more prolonged the low temperatures, the more risks to your tomato plants slowing down, but I think they're a lot more hardy than you suggest.

Nope, the plants will survive cold, as along as they don't get frosted. The problem is that if they get prolonged periods below 10 C they can stop growing almost altogether - if that happens then you will certainly get a reduced crop compared with what you would have had if they'd been kept warmer.

I try to err a little on the safe side with my advice re temps too - as predicting precisely how cold the weather will be and for how long when it comes to positioning your plants, is a difficult art in my experience.

[bramble]

My tomatoes are out in the unheated greenhouse for the past 12 days.
I cover them every night with layers of fleece and lots of newspaper.
I keep them on the dry side so there is a minimum of moisture.
They are doing fine.
My peppers and chillies are also along side them and all looking good.

[Ani]

The 10°C at night thing has to be a myth. Continental Europe often has colder night than this in July and August.
I used to be a girl scout (back in Czech Republic) and during nights watch in our summer camps we always measured and logged temperature and typical temperature (second half of July) was 9°. August nights are even colder. You can have 30° day temperature and then 9° or less at night and tomatoes do well.

[nickdub]

You'd need to measure the temperature in amongst the tomato plants at night to get a better idea of what's actually happening. With hot days where the ground warms up considerably and at the time of year when there's lots of plant foliage, its quite likely that the micro-climate around the tomato plants is significantly warmer that out in the open, where night time minimum temps are recorded.

[Jungle Jane]

The plants are really young & tender at the moment,once they’ve had time to harden up,by July like you say,they’d have hardened up & can take a couple of low temperatures,difference is in July it’s usually warm during the day which picks them up from a cold night. Now where we are now it’s cold in the day & cold at night,it’s different.

[Ani]

Nickdub: That's certainly possible.
Having tomatoes out when it is 12 day temperature and 8 at night will almost certainly slow them significantly. But few cold nights in summer won't hurt them. I don't think there is some magic line like 10 is fine and 9 isn't.
My grandmother in the Czech Republic moves her tomatoes out in mid-May, which is traditionally last frost date in central Europe. She doesn't care about night or day temperatures, just about the frost risk.
On the other side, we here have last frost date in mid-April but most of us wouldn't move tomatoes out now because it's generally colder. Which would imply that the average temperature may be more important than night minimum.

[veggiechicken]

There's a big difference between the "err on the safe side" advice we give to someone who may be growing tomatoes for the first time and to those who have more experience and accept that leaving plants out on colder nights brings some risk.
I've seen too many members who are heartbroken when their plants die or turn purple because they thought it would be warm enough overnight. Its not right to encourage them to run risks without making it clear there may be consequences.
My toms have been in the GH for a couple of weeks but, they're not in their permanent positions yet and I still have the option of bringing them in if a really cold snap is predicted. Also, its not the end of my world if all my toms were to die as I know I still have time to grow more. New growers aren't quite so relaxed about success or failure as I am.
So, my advice to everyone is, toms need 10C to be happy in a GH.

[nickdub]

I'd always go with someone like your Gran who has loads of practical experience when it comes to gardening. If I was living somewhere nearby to her, I'd ask her what she did, and do the same thing myself.

The difficulty is how well would what she does translate into growing plants here in the UK, where on the whole we are "blessed" with a much more maritime climate which comprises less extreme temperatures, but certainly for those of us in the West of the country much damper air etc.

It would be an interesting experiment to to try exactly the same approach here to tomato growing as your Gran has, and to document the results. If you fancy giving it a try some time, I'm sure we'd all love to find out how it goes. :-)

As an aside it could also be that the varieties of tomatoes your Gran grows has an impact on the success she gets. Its by no means the case that the commonly grown types which commercial growers produce will be anywhere near the best choice for amateurs such as ourselves, who are generally trying to grow crops in much less than optimum conditions. So a tomato variety which could stand low temperatures and still grow on well, would be very good news for a lot of us.