Video: Overwintering Tulips in an Unheated Tunnel

I'm here in our field tulip trial, here on the Johnny's Research Farm in Albion, Maine. It is April 14, and I wanted to take a quick look at our field tulip trial. These usually start blooming for us in the beginning of May. Our tulip season, once it starts, is pretty fast and furious, and it always feels too short, so one of the ways that we extend our tulip season a little bit longer is by planting into an unheated tunnel, as well as into our field planting.

I just wanted to show our field planting here, as a point of reference. This is, again, the middle of April. These have 2 or 3 more weeks, probably, before they're going to be blooming and we'll be able to harvest from them. Next, we'll head out to our overwinter tunnel and take a look at the tulips there.

I'm here in our overwinter tunnel planting. I'm here in front of our tulip trial. As a follow-up to what we saw out in the field a few minutes ago, this is what an overwintered tunnel planting of tulips looks like for us, in the middle of April. So it's April 14. We're still, probably, 3 weeks out from when our field tulips will be ready for harvesting, but you can see that there are a lot of blooms here that are ready for harvesting, and a lot that are coming on, as well. I just wanted to give a sense of the seasonality and how, by planting in the tunnel, we're able to extend our tulip season by about 4 weeks, depending a little bit on the year.

Both in the field & in the tunnel

So if you are planting tulips in a tunnel, a few things that we do… We plant the same way we would plant into a field, into a trench. We dig a trench along the bed, 6–8" deep. We plant the tulip bulbs in the base of the trench, tightly planted — same as we would for the field — they're all shoulder-to-shoulder; we pack as many in as we can. Then we cover them over with soil.

What we do differently in the tunnel

One thing that we do differently from the field planting is that we water-in the tunnel tulips heavily at planting — they're not going to get the fall rains that a field planting of tulips probably would. So we want them well watered while they're rooting in, in the fall.

We also will plant our tunnel tulips a little bit later than our field planting. Our field tulips go in the ground in the middle of October, right around October 15, then we usually, sometime in the next couple of weeks, we'll get this planting in. It's not as much of a rush because we don't worry about the ground freezing here. We have a little longer window for getting these in the ground.

OCTOBER

1. Plant them.
2. Water them in.
3. Then we leave them for the winter.

LATE FEBRUARY/EARLY MARCH

We typically start seeing shoots emerge from the soil in the beginning of March.

Another thing that we do a little bit differently from the field is that, at the end of February and/or the beginning of March, we do provide some water to this planting, as well. Those bulbs are starting to grow and to push up through the soil; they're going to need some moisture. In a field planting they would naturally be getting that from snow melt; in the tunnel, they aren't getting that, so we will bring in a little bit of water, to water them in again, late February/early March, depending on the year.

Another thing that we have done as well, before the shoots have emerged, sometimes, we have just shoveled in snow onto the beds and let the snow melt down into the beds. I think it really depends on what works for your system, but definitely, once the shoots have started to emerge, then we hand water, typically.

Then, once our irrigation system is able to be up and running, we put drip irrigation down these beds. This bed currently has drip irrigation on it, just to make sure that these are getting enough water as they're actively growing. They grow really fast and they put on a lot of vegetative growth, so we're wanting to support that.

APRIL

Finally, we typically start seeing things color up in here — usually, the first week of April. It can and does shift a little bit depending on the spring, So if it's a cold, cloudy spring, then bloom dates can shift by a week or two. Or, if it's a hot, clear sunny spring, there's a lot more solar gain inside the tunnel, so that will push things along a little bit faster.

You can extend your season, too, within the tunnel planting, by choosing from earlier-blooming and later-blooming varieties. We do have different types here:

• First, we have Darwin hybrids, which are right in front of me. They tend to be the tallest, with really large blooms.
• Further down the line, you can see some double early and double late tulips.
• And behind that, we have some parrot tulips and some single-blooming varieties.

So, the broader your assortment is, the more likely you'll be able to have a longer season in your tunnel.

If you're looking for more information on variety selection and how to extend your season that way, you can find more information on all of these varieties here in our Tulip Grower's Library.

If you would like to extend your tulip season beyond what you can do in a field and you have access to a tunnel, this can be a really simple, straightforward way to add another 3 or 4 weeks onto your growing season.