[azk404]

Hello.

I have some tomato plants being propped indoors at the moment and I intended to start taking them outside to harden them off today. I have noticed on 1 or maybe 2 of my variety's that the stems at the very bottom have become thinner than above it, photos below. I have some Golden Sunrise tomatoes which seem fine but the San Marzano are effected. The plants are about 20-50cm high at the moment so will start hardening off today.

I have googled the issue but not sure which problem it could be if any. Any suggestions to look into would be great?

I have also noticed several very small black flies hanging around so not sure if that is related, photo below.

Cheers
E

[jambop]

Could be wrong but I think that is normal. I have certainly seen it before on my tomatoes ans never had a problem getting bumper crops. That plant should be about four inches or more below the soil level anyway it promotes good rooting.

[JayG]

The flies will be fungus gnats, which sound more alarming than they are - there are several species but rarely cause any damage.

Not sure about the tomato stems - can't see any signs of actual infection or damage, and the rest of the plant looks healthy enough as far as I can tell.
Others may have a more definite answer - I would suggest keeping a close eye on them, because if they do collapse they will need to be binned pronto to avoid potentially infecting the others.

How are you proposing to harden them off?
Even in London, too early to be hardening them off outdoors I would have thought...

[Yorkie]

Fungus gnats can often be a sign of over-wet compost.  Make sure you don't over water.

[azk404]

Morning,

As of now I have put some thin canes down the side to prop them just incase conditions outside get a tad breezy for them although now I am having second thoughts about starting the process.

I intended to start putting them out in a shady corner, although they will get a bit of breeze as its on a balcony. The next couple of days are highs of 19-22 here, which I thought would be ok, but after that it drops to 16 so maybe best to postpone for a while.

The plan was to put them out for about 10-12(14) days starting at about 2 hours and increasing it as the days went on. On the 8-10th day I would leave them more into the evening and on 12-14 put them leave them outside night. I wasn't going to use horticultural fleece but maybe could have some just incase. How does that sound? 

They are sitting by a window so I might also start opening that put to possibly simulate a use cold frame.

Cheers, keeping an eye on them for now but it's just a bit worrying. I don't think them are being over watered but I will look into that as well.

[JayG]

Sounds like a sensible plan - the key factor will be the temperatures in a fortnight's time and beyond - anything below 10C will stop them in their tracks, and possibly even kill them, but you seem to have a good handle on their care requirements. 

[azk404]

I have begun hardening them off about 3 days ago and there all looking fine, although the plants are definitely too tall for their current pots. I can probably keep them in till the time to plant them in their final spot but the only thing is the night time temperatures next week when I would be planting them are 4-9c.

Either I keep hardening then off and wait till around 13th when the nights are 10+ or is this a good time to use some garden fleece?

[JayG]

A single layer of fleece is quite effective when laid on the ground as it deflects the cold sinking air and stops it reaching whatever's underneath.

To insulate taller plants, you really need a thicker layer, which would probably need support to avoid damaging the fragile young tomato plants, which all starts to get a bit of a faff!

I'd be inclined to wait until the coming cold snap is over - even mid May is quite early to be planting tomatoes outdoors in most parts of the UK.

[azk404]

Thanks for that by the way, I've waited and they seem fine for now