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Starting Tuberous Begonias Under Lights

Posted by jimnoak 5b - 6a (My Page) on
Thu, Dec 7, 06 at 3:19

If anyone has some advice, where can I buy the starts of some special begonias, and I'd appreciate knowing WHEN should I start them under lights so I can plant or pot them here in Southern Illinois next Spring?

In the past I just spend tons per year to buy these plants (if I can even find them) and in the past I haven't tried to overwinter them. Last year the squirrels got to them, but I've learned how to maybe defeat the squirrels next year.

In the catalogues I get and the websites I've found... I'm not seeing anyone who sells the hearts of these types of incredible begonias like I used to buy and dispose of. (duhh jim)

Next summer I'll build a greenhouse again, but for now I'd just like to get a head start on the begonias because wth shade conditions at my lake, they do better than anything except hostas.

curious and lost here in southern Illinois...


Follow-Up Postings:

RE: Starting Tuberous Begonias Under Lights

You can get tuberous begonia seed from Antonelli Brothers in Santa Cruz. I figure the seed grows just like any other begonia seed I've tried so far--light and warmth (I use a heat mat and fluorescent grow lights). Antonelli's also has tubers ranging from really little kinda generic ones up to gigantic show begonias in quantities from 1 to gazillions.

I'm guessing that it would be good to start begonias from seed as soon as possible so they are big enough to set out when the temperatures warm. I started mine too late, and had to drag in all my little seedling pots to overwinter under grow lights. Hey--it's an adventure :-)

Stokes Seed has a whole range of tuberous begonia seed, and I don't think it's too expensive considering the quantity you get.

RE: Starting Tuberous Begonias Under Lights

Antonelli Brothers have moved, I think they are in Watsonville Ca. now. Purchased seed from them several times. I had really good luck with germination, and got some very good exibition quality Begonias from the seed.


RE: Starting Tuberous Begonias Under Lights

Glad I read this post. I have been looking for begonias and have now gone to the Antonelli website. Will be placing an order soon! If anyone is interested, this is their website:

RE: Starting Tuberous Begonias Under Lights

Here's a hint that worked for me last year:
The tuberous Begonia's I've grown from seed have formed very small tubers by the end of the first season, some smaller then my little fingernail. To make the tubers bigger last September I pinched out all the flowers and buds, and the growing tips the first part of September. Hard to do, but it really does help. I also gave them a dose of Potash, treated all my tubers this way and what a difference. Got this tip from the B.C. Fuchsia and Begonia Society's newsletter. The article was originally from the Canadian Begonia Society's September/October 2001 newsletter.


RE: Starting Tuberous Begonias Under Lights

Hi..starting seed is quite doable. Growing them in So Ill may be a bit tricky. But that's another issue for now.

Yes lights..heat @ about 75. Be careful about too much bottom heat. Even a mini-heating pad/baged in plastic set on "low low" can be a bit too much. If you do use a heating pad for heat raise your germination container up an inch or two.

I suggest you use a plastic table grape or kiwi container. The have lids and vent holes (will keep the humidity high.)

Make sure you microwave the growing medium/use a fungicide for the initial watering and/or misting.

B seed is extra fine. I suggest you divide your seed into 3 or so portions (errors/stay under 100 seedlings.) Freeze the remaing seed in a air tight Glad sandwich pouch. It'll keep for years.

Use a playing card or evelope end to strike the mini-rows an inch apart. Your should have room or 6 or 7 4" rows a quarter inch deep is deep enough..use a pencil to very lightly cover the seed. The initial misting will carry the seed into the mix far enough.

Antonelli seed has a good reputation for germination. We just returned from NZ spent some time at Beautiful Begonias on Golden Bay (

They use Antonelli seed (have been for 10-15 yrs)..must have 2-4k seedlings which customers tag (see blooms)and get the tubers at season's end. They get 90% plus germination/speak highly of Antonelli seed.

Another excellent source is Blackmore & Langdon in the UK ( B & L are the gold standard for commercial exhibition quality tuberous begonias. They package their seed in a variety of packets..I'd suggestthe packet containing 6 named colors. Expect to pay $50 or so dollars when your done (seed, post, inspection.) The cost from Antonelli will be comparable (if not a bit more (

Germination should take from 7-20 days. Good two leaf seedlings in 6 weeks. Prick them out into a six pack...keep on sizing up as they grow.

Granted it would be perferable to seed in Feb or late Jan..but you should make mini-tubers even with an (early) April seeding -- and a bit of luck.

We lived east of Cobden for close to 40 years (farmed/gardened) while I taught @ SIUC. I found begonias took care I wasn't too good at providing. Here (west of Seattle) we have a micro climate that is great for begonias (and not hot enough for good tasting tomatoes.) So it goes.

Before I forget, find a copy of Mike Stevens' "Begonias" (

Good luck, Ted Buila

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