Topic: Begonias - advice please.

[Grandma]

Can anyone please tell me how I can save the tubers from my lovely begonias for next year? They're still flowering beautifully but I guess I'll have to do something before the first frosts.

They're all in containers - should I dig them up or dry them off in their pots?
If I have to dig them up, how should I store them?

They're the 'non-stop' types, bought as little plants in the spring.

I have an unheated greenhouse - if that's any help.

Thanks for any advice you can give. xxx

[Baaaaaaaa]

I grow a few large double begonias that came from Blackmore & Langdon (ie the £10 - £20 a tuber ones)

Mine are in 12 inch terracotta pots (the £1.00 from B&Q/Homebase type)

About this time of year, while they're still flowering, but are risking frost, I move them into a sunny (frost free)  porch. There they can continue flowering for as long as they like.

Also, they are out of the rain. From now on I don't water at all. The tops will eventually die down and the compost dry out. Remove the tops (they should just fall off if ready) to stop any diseases getting into the tuber and move into frost free storage (I use the garage). DON'T WATER.  By leaving in their existing container, the roots ae not disturbed.

In late March when things are starting up, un-pot the tuber, and re-pot in fresh compost. This compost will be slightly damp. This will provide enough moisture to start growth. DONT WATER - you'll rot the tuber.

If the temperature is high in April, like this year, and the compost is drying out, I might give them half a cup of water - but no more, and only once.

When the season is well under way, late April, early May, the new growth should be just poking through the top of the compost, I put them outside and only then start watering. This kicks them int growth and away they go.

This is not perfect in anyway, but I do get about 75-80% success.

The trick is if they are sitting in damp soil when dormant, they will definitely rot. When dormant, they don't need any water, so don't give it to them.

I'm sure others will have different techniques.

[Grandma]

Thanks ever so much, B! xxx

[laurieuk]

I grow a collection of B&L begonias and my method varies slightly but we all do things different. I let mine dry form about now and leave in the pots. Around Christmas I clean all the soil off fix the labels with elastic bands and keep in a large pot in the spare bedroom ,cold but frost free. I restart mine about mid March as I want them in the best of condition for shows during August. I have Had trouble with vine weevil and now use Levington container compost with has the insecticide in it. No more troubles since. I have managed to get some 10 inch square pots which are more stable for the plants that can get up to 3 ft in diameter.

[honeybee]

Hmmmm, i always lose mine over the winter, and after reading this was wondering?
I dont have a porch or greenhouse even, but my begonias are also in a deep terracotta pot, so Baaaaaaaa if i simply lifted the pot and put it into the shed over winter, then i guess my begonias would have chance of survival?

[Baaaaaaaa]

So, you will loose the extended flowering season, but provided that you remove the dead top growth to prevent disease, then there should be no difference.

Not sure what happens if you remove the tops before they die down. The plant will looses some photosynthesis time, but thos can be made up for with a late potash feed.

Frost free and DRY is the key. It doesnot guarantee success, but DAMP will guarantee failure in the form of tuber rot.

I use standard multipurpose with a handfull of added grit. This provides sufficient moisture retention during the growing season and adequate
drainage to dry out the tuber in the Autumn.

If you have used a moisture retaining medium, I suggest you re-pot into something much dryer for the Autumn, perhaps even sand. Laurieuk's air drying is also a good idea, but only after the tuber is completely dormant.

With a current 100% loss, you have nothing too lose. Might even see you on the showbench next year !

[valmarg]

Slightly different method, grandma

Leave them until the frost has killed off the top growth.  Dig up/take out corms from containers.  Keep completely dry, but frost free, during winter.  A bit like dahlias.

Early Spring (March/April) you can lay the corms on a bed of compost and start to water.  When they start to shoot, you can cut up the larger corms to provide new plants, or you can take cuttings.  I find a 50/50 mix of compost and vermiculite gives good results for rooting cuttings.

valmarg

[Grandma]

This is really excellent, thank you all!

I'm trying B's 'drying off in their pot' method for the ones small enough to move but I have two BIG terracotta containers with multiple tubers - (I just assumed I would have to leave them to their fate  :() - now I can try the 'valmarg method' on those!  :) :) :)

What a kind lot of peeps you are!  :-* Thank you.

[Shirley]

Last year I over wintered begonia tubers for the first time with some success.  I dug them up, let the tubers dry out by hanging them upside down until the top growth had died down.  I then kept the tubers packed in shredded paper.