Ashley Swansong: Hey, everyone, you may have heard of tuber forcing or bulb forcing.

We're here with horticulturist, Liz Hamilton, who's gonna demonstrate tuber forcing using her canna lily tubers as an example.

And don't forget to subscribe to Modern Gardener.

Can you start by telling us what tuber forcing is?

- Yeah, so you're just trying to start your plants a little bit earlier so that you have blooms a little bit sooner.

For cannas, often the blooms aren't what you're looking for.

It's really the foliage that makes the plant the star of the show.

And they tend to wake up really slowly if you plant them directly in ground.

And that's because they really like their tropical, and so they really like in-ground temps that are ranging between 75 to 95.

And if you go right out in May, after the first danger of frost is passed, and you pop 'em in the ground, the soil, which takes a lot longer to heat up than the ambient air temperature, is gonna be much cooler, and you can see potential rot.

And then the other issue is gonna be that they're just cold, and so they're just gonna wake up really, really slowly.

And if you want that instant impact, just like you would buy them at the store, waking them up earlier gives you an opportunity to get them to a certain growth point by the time it's super warm, June 1st, and then you can plunk them in the ground and they're already beautiful and luscious in your landscape and there's no waiting.

- Awesome.

Let's do a demo.

- All right.

- Let's plant your cannas.

- So when I put everything together, it's all in peat moss, and there's nothing else in there just peat.

And so it would be a waste to just throw this away or not do anything with it.

So often I only have a tiny bit of actual potting soil and then I backfill with the peat that's that's there too so that I'm utilizing it.

You can use any basic granular fertilizer that has an even number of NPK.

So like a 10-10-10 or a 12-12-12, any of that would be fine.

- Ooh, Look at that.

- So here's a full-- - Wow.

- Yeah.

So it grows laterally along the side and then it has growth points from these eyes.

And so this is obviously too big for this pot.

So what I'm gonna do is split it in a place where it's got a couple different growth points.

So there, and like I said, you can be not delicate with them at all.

So this one right here is gonna end up with at least one, two, three, four growth points.

- Wow.

- And so that's plenty for this pot.

This one's an aquatic canna, and so what I will do, it's eventual resting places is in my pond down here, but what I'll do is pot it and get it up and going, and then when it's time to put it outside I'll actually put it in an aquatic pot, which is like a bowl, and I'll plant it up with clay so that it doesn't float around the pond and it'll go in the pond.

- Wow.

- So we'll take some of this peat.

Little bit of potting soil, little bit of fertilizer, and top 'em off with all this peat that I got extra.

And then if it's windy out all the peat goes right in your face, so I apologize.

- In my teeth.

- Yep.

No.

Yeah.

And you can start them in smaller pots, but they're such a vigorous grower, that if you start them smaller, you'll regret-- - End up having to transplant 'em.

- And you don't wanna make extra work for yourself, especially when you're inside.

- Uh-huh.

- And these, by the time they're ready to go out, the roots will have filled all the way through these pots.

They'll be bursting at the seams to get out of this, by the time June 1st rolls around.

I could have done this a little bit earlier.

We're a little late, but I was outta town.

So we're starting all last week of February right now.

But I could have done it as our early as late January, first week of February.

Cannas are slow to start, but once they're up, they're big.

And so one of the things to remember is they kind of take up space in their pots, but once they really start growing, you need the space.

- Yeah.

- And you have, there's about a month, where they're quite large, and you can't put them outside yet.

- Okay.

- So something to think about.

- Okay, yeah.

It's like a sculpture in your house.

You've gotta have that corner.

- Yeah, you have a place where they're gonna go.

- That's good to know.

- And they like full sun, so wherever it is, either under a direct grow light, or in a nice, warm, south facing window.

- Okay, cool.

- And you don't wanna water 'em a ton right as you put 'em in, because right now they don't have any roots, right?

Even though they're sticking out there's nothing valuable in these leftover roots that were on there.

All the energy is in stored inside those rhizomes.

And so if I dumped a bunch of water on 'em and then put 'em on here, then they potentially could rot because there's no roots sucking up that moisture.

- Yeah.

- And so I'm going to lightly water them just enough to kind of like get them up and moving.

I don't recommend an at home soil meter because they go bad really quickly, and you never know when your soil meter's gonna go bad.

So like the probe can just die, and then it just is telling you you have plenty of water and you don't, or it's telling you you have none and you have too much.

- Okay.

- So I don't use 'em.

I just kind of get in there and see-- - Feel?

- And if I lift it up and it's really light it's clearly not enough water or not any water in there.

- Yeah, totally.

Yeah.

- So I'll just kind of watch 'em really closely.

But as soon as I start to see active growth then I know that there's active root growth below the soil as well, and then I'll start picking up the watering.

And then the more they fill out and the larger they get, the more water they'll need.

And so it'll be kind of like we start slow and then we speed our way down into summer.

- Yeah.

- In terms of watering, and that'll be with anything I start, but cannas also.

We just wanna make sure we're not rotting those tubers.

And it's the same with dahlias when you start them, and then gladiolus, if you start them early indoors, you just put out a little bit of water just to kind of get them going so that they know it's time.

And then the lighting will help and the sunlight will help.

And then we should start to see some growth here in the next couple of weeks.

And then again, it'll start, it'll go from like almost nothing to something almost overnight.

It'll be like magic.

- Wow.

So then in come June, you'll take 'em out, and that's when you put 'em outside?

Yeah.

It's weather permitting.

So you'll hear a lot of, you know, wait till danger has passed, and then they'll say for Northern Utah that looks a lot like Mother's Day.

If it looks really good on Mother's Day I'll look again at that 15 day forecast.

And if I'm solid, then I plant.

But I will say that in the last couple of years, we've had some really unusual late cold snaps.

and almost into June.

Like these guys, if I had put them out, would they have survived?

Yes, because the ground wasn't frozen and all that energy stored in the tubers.

But if I'd had 'em started, all of that tender new growth that can't handle those temps, it would've died to the ground again.

- Oh.

- And so all of my tuber forcing work, all of the growth that I babied all year long, it would've been for not because it just would've died to the ground and then I'm waiting again.

- Well, thank you so much.

All of this has been super helpful information.

- [Liz] Good.

I'm glad.

I'm glad you guys could come over and watch.

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