Fruiting Houseplants

Fruiting Houseplants

Part of Ep. 502 Indoor Gardening

Perk up your winter with lemons you've grown indoors.  UW-Extension Fruit Crop Specialist Teryl Roper discusses indoor fruiting houseplants that you can grow at home.

Premiere date: Mar 31, 1997

TRANSCRIPT+
Wisc Gardener Transcript: 

Shelley:
Wouldn't it be fun to grow your own coffee beans indoors anytime of the year? We're at Felly's Greenhouse. With me is UW-extension Fruit Crop Specialist, Teryl Roper to look at indoor fruiting houseplants that you can grow at home. One of the first ones I started with was the meyer's lemon. It's a pretty forgiving plant. It sits in my southeast bay window and it doesn't seem to complain very much.

Teryl:
Meyer's lemon is a good place to begin. It doesn't have very exacting environmental requirements and given even moderate care you should be able to get attractive fruit like the one that's in your hand.

Shelley:
Real lemons! I could make lemonade in the middle of winter.
Teryl:
That would be wonderful.

Shelley:
Now, this is one I've also tried, a pomegranate. And I have not had quite as much luck with it.

Teryl:
A pomegranate is a lot more exacting in its requirements. And if it's not given proper care it will drop all of its leaves and look pretty much dead.

Shelley:
Yeah, I had a dead one there, for quite a while. This one is actually starting to form some fruit. The seeds of this are edible. They're great in salads.

Teryl:
Right. A plant this size is really nice to take home to see if you have the conditions and skills to grow fruit indoors.

Shelley:
And it's easy to move around and try to find the right spot for it, too.

Teryl:
That's right.

Shelley:
You told me that I can grow strawberries indoors.

Teryl:
These are standard june-bearing strawberries just like you plant outdoors in the garden. We put these in pots about ten days ago. In another month or so, we'll have flowers and fruit.

Shelley:
Imagine harvesting fresh strawberries in the winter that'd be great. Most of my fruiting houseplants sit in my bay window. Some winters they do great and I get lots of fruit. Some winters, they just sit there. What do I need to do to ensure success with indoor fruit?

Teryl:
The primary limitation to growing fruit indoors in Wisconsin is having enough light. Our winters are dark, the days are short and we have cloudy days. We simply don't get enough light.

Shelley:
And the winters are long, too.

Teryl:
We can supplement the natural light with artificial light. A simple way to do that is with a standard fluorescent fixture, like this one that's available from most discount or hardware stores. This fixture has standard cool white bulbs in it. They are very strong in the blue wavelengths. If you use cool white bulbs you should probably supplement that with incandescent bulbs-- just standard light bulbs to give you more wavelengths in red.

Shelley:
What do I need that for?

Teryl:
Photosynthesis requires energy in both the blue and the red wavelengths. So, in order to be best, you need both blue and red light. Or, you can simply replace these bulbs with the grow tubes.

Shelley:
Then we'd get the full spectrum?

Teryl:
It would give you the full spectrum.

Shelley:
What is this high-tech looking light?

Teryl:
This is a quartz halogen fixture. Again, they're available at most discount and hardware stores. It gives off a lot of energy. It's particularly rich in the red wavelengths. The one drawback to them, though is they also produce a lot of heat. You need to keep those about a foot and a half to two feet away from the tops of the plants.

Shelley:
How close should the fluorescent lights be?

Teryl:
The fluorescent light could be quite a bit closer, maybe 15-18 inches away from the top of the plant. We want them as close as we can to get as much light energy as possible. But yet, far enough away so we don't burn the foliage.

Shelley:
Without cooking them. Do we leave these on 24 hours a day?

Teryl:
They probably need to be on 16-18 hours a day. Plants need a little down time just like you and I do.

Shelley:
Another issue in growing plants indoors in the winter is humidity. We don't have a lot of it in Wisconsin in the winter.

Teryl:
That's right. Most of these plants are tropical to subtropical species. And they're used to hot, steamy jungles. If we gave them those kinds of environmental conditions we'd condense water everywhere.

Shelley:
We could have rotting floor boards, window sills.

Teryl:
That's right. So, we want to increase the humidity locally. An easy way to do that is simply by misting the plants with an ordinary spray bottle. If you do that a couple of times a day the plant should be very happy. Another way to do that is with a pebble tray. Take an old cookie sheet, spread some gravel on it and set the plants on top of the gravel. Then, pour some water over the gravel in the cookie sheet.

Shelley:
So, we never have the plants actually sitting in water.
Teryl:
That's right. They're sitting above the gravel. The water will evaporate and increase the humidity locally.

Shelley:
Temperature seems to be another important issue. My meyer's lemon sits in a bay window that's very drafty and it doesn't seem to mind, but other plants really suffer.

Teryl:
Again, these are tropical to subtropical species. They need warm temperatures. Particularly for those who are out of our homes during the day and we turn the temperature down before we go to work and we turn the it down when we go to bed, plants simply don't get enough heat. They like the temperatures in the 70-72 degree range during the day when the lights are on. At night, you can set the temperature down. There's going to need to be a little bit of a compromise between the fuel bill and the plant's happiness.

Shelley:
Of course, the plants are most important! What about getting fruit? That's the biggest issue with growing fruiting houseplants. There is a trick to it, I know. My coffee plant sits out on the porch in the summer it blooms there and it does fine; I get lots of fruit.

Teryl:
Outdoors, there are lots of insects that do the pollination. But most of us don't want to share our homes with pollinating insects, like honey bees.

Shelley:
The lemon blooms indoors in the winter so we'd have a problem.

Teryl:
We need to do the pollination ourselves. That's easily done with a cotton swab. Just take some of the pollen off of the anthers and deposit it on the stigma. Or, you can simply take two flowers that are close and rub them together.

Shelley:
The lazy gardener's way-- my way! Do we have to worry about eating the fruit from these?

Teryl:
If you've purchased a large specimen from a greenhouse they will have treated it with a pesticide. Greenhouses are difficult pest environments. So, you'd probably want to wait a year before consuming fruit. If you've been growing the plant at your home for a while and you haven't used pesticides, go ahead and eat the fruit.

Shelley:
If you're going to eat it, avoid pesticides at home.

Teryl:
That's right.

Shelley:
Thanks, Teryl. So, consider one of these plants for your indoor garden.

EPISODE SEGMENTS+

Funding for The Wisconsin Gardener is provided, in part, by The Wisconsin Master Gardener Association.