Is it OK to start hardening off now?

[SammieB]

Having started my bush tomatoes, cucumbers, courgettes and squash on a windowsill, for the last couple of weeks or so I have had them in my coldframe/mini-greenhouse thing by day and have been bringing them back in to the house at night.
I know I need to harden them off before putting them out and so I have a plan - does the following sound OK?
From tonight I plan to leave them in the coldframe day and night. The forecasted night-time temps in my area, from and including tonight, are 11, 10, 10, 9 and 8 degrees. Is it OK to do that now? I was advised to keep them at 10degrees as a minimum but does this apply when you're trying to harden them off?
For the next few days after that I plan to increase the amount of ventilation both in number of panes opened and for how long each day.
Finally putting them outside day and night for a few days before planting out.
Am I jumping the gun starting tonight do you think?
Thanks, Sam

[SammieB]

Arggh, forecasted temp for tonight now only 8 degrees. Have I jumped the gun?

[Bill HH]

I think they will be fine, my tumblers have been out quite a while, I don't think 8 c will hurt them for a short while.

[SammieB]

Thanks Bill, I was starting to panic as I'd hate to see my babies keel over now! Does the min 10 degrees not apply then when hardening off then?

[BertieFox]

The best thing to do is to talk to your elderly gardening neighbours in the Peak District at similar elevations. My best guess would be that you will be unlikely to get any frosts now, so it is a balance between a check to growth resulting from low temperatures outside to a check to growth by leaving things in pots too long inside.

I would just increase the hardening off for a few days by placing the pots out in the open each day and putting them in the frame for the night. Planting out and protecting with fleece, which is really quite cheap to buy, would probably be the best option.

[Bill HH]

Thanks Bill, I was starting to panic as I'd hate to see my babies keel over now! Does the min 10 degrees not apply then when hardening off then?

As I understand it most plants will not grow under 10C, but a brief period of 8C is not going to check them. When they say a minimum forecast of 8c that is the lowest in the night and may be only for a brief period. As Bertie says you have to balance that risk against the harm of not putting them out.

[JoeDaStudd]

I've got mine in the greenhouse and was running a bit (well a lot) behind so just put them straight in there (seeds). The cucumbers went in 3 weeks ago and are doing great. The tomatoes I was really late with and didn't plant unit about a week ago and they are doing well.
With the extra light and heat we seem to be getting its well worth putting them outside now if they are going to be under cover.

Just need to rig together something to water them while I'm away for the next two weeks...

[AllInContainers]

With hardening off, you are exposing them to daytime conditions, but still protecting them from night conditions, so I can't see any problem at all with night temps of 8C. All my tender plants are now planted out, so I've committed myself for this year

[SammieB]

Hmm. Perhaps I shouldn't be so wussy. Had planned to harden them off slowly and plant out at end of month but it sounds like I should be getting them in the ground sooner. I've got about a dozen tomatoes and half a dozen of the rest, which is probably more than I need, so I guess I could take a chance on half of them.