Convention has it to repot in spring, while the day length is increasing, but that is looking like a bit of an emergency. I'd just go up one size, now, but you may need to repot again, come April. With rhizomatous Begonias like that, I prefer to use a fast draining mix--cactus mix, where I live, but there is probably a John Innes mix to match.

So your saying a soil based instead of soiless?

No, not soil based. Cactus mix in the States is completely soiless, and I thought that the John Innes mixes were also....Maybe I'm mistaken in the latter. :]

Oops! I guess that I am mistaken! There is loam soil in the John Innes mixes. If a soiless cactus mix isn't available, mix up 4 parts by volume bark fines (1/4 to 1/2 cm diameter) 2 parts pumice, and 1 part sharp sand or grit.

Ok thanks very much in u.k. John innes is soil based thanks for your help.

I always thought begonias needed a dormancy period. Am I mistaken? Maybe there are different types but I always had to dig mine up, wrap the corms in newspaper and store in a cardboard box down in the basement until Spring. Maybe that's why I don't have them anymore! Have you seen the Rex Begonia? Give it a google. The leaves are more striking than the flowers. They are definitely going on my front stoop next spring. As far as re-potting goes - listen to Tug. He'll do you right! Sorry if I'm a little chatty today. It's almost 100°F today in NY and it's 8pm. Rain please come soon! Uggh.

Hi, Bathgate! From what I hear, the tuberous species need a dormant period, but what Young_Alastair is showing is one of the rhizomatous speces, which include the Rex Begonias. They get sleepy in the winter, but most don't go fully dormant. I fully sympathise with the heat! It's been over 110º for weeks on end, here, with nights in the 90's. At least even now in our monsoon season we don't have to face the kind of humidity that you are probably enduring.

Yes the high humidity just exacerbates the high temps being right near the Atlantic. I shaved my head today which helps a little. The storms are coming tomorrow with a fury. That's really what we need.

Come to the u.k. people actually grow their hair here to keep warm.

Anyone who has hair to grow should thank their lucky stars.

Good morning

Thank you for your email and enquiry. If you think your plant is big enough then you can repot. This should be in a pot 2-4cms bigger than the present one. We would recommend a good quality indoor houseplant compost available from a good garden centre.

Kind regards Dibley's

What? Who?

From Dibley's the plant people

You can indeed buy Cactus Compost in the UK. There is some in my shed to prove it...

Oh! Sorry Youngalistair, I didn't twig to it being a copy of info sent to you. I've used ordinary houseplant compost before, and had problems with fungus and collapsed soil structure. I'll admit that it wasn't a particularly good brand, though