One fun winter project for both children and adults is to sow citrus seeds and watch them turn into charming little houseplants. It really isn’t hard to do: just start from any fruit picked up at the market. Obviously, you do have to get a fruit that bears seeds (navel oranges, among others, are normally seedless), but otherwise you can sow the seeds from any citrus – orange, lemon, grapefruit, clementine, etc. – and get a beautiful foliage plant.
But will your “living room citrus tree” produce fruits one day? Probably not, but at least you’ll have a leafy, branching indoor shrub to admire.
From Seed to Small Plant
Here’s what to do:
You have to start with fresh seeds: citrus seeds don’t store well.
Cut the fruit open and extract the seeds. Clean them to remove any pulp, then rinse them with water. Some people recommend peeling off the outer envelope of the seed, but in fact that isn’t necessary.
Moisten a cup or so of standard potting mix and pour it into a small pot. Sow the seeds about ½ inch (1 cm) deep and cover lightly. Sow several seeds in the same pot if you want.
Next, seal the pot in a clear plastic bag or place it in a mini greenhouse.
Place the container in a brightly-lit location, but away from direct sun, otherwise the temperature inside the “greenhouse” can build up to dangerous levels. A spot under a fluorescent lamp would work well.
The spot you choose should also be relatively warm (70˚F/21˚C or more). Be forewarned that a windowsill may be too cool if you sow the seeds in the middle of winter.
Normally, citrus seeds germinate in about 3 to 6 weeks. The first leaves are cotyledons and won’t look like citrus leaves, but true leaves will appear very quickly. Sometimes more than one plant will grow from a single seed. This is called polyembryony. It’s generally a rare phenomenon in the vegetable kingdom, but quite common in citrus.
When the first true leaves appear, remove the plastic bag or mini-greenhouse and place the pot near a sunny window or under a fluorescent lamp.
After 3 or 4 months, divide the plants if there are several in the same container, planting each in its own pot. Don’t hesitate to toss extra plants into the compost bin: 2 or 3 indoor citrus trees are about as much as most people would want to handle.
Fairly Easy to Grow
Citrus fruits make quite decent plants, adapting well to the growing conditions available in most homes.
They’ll need as much light as you can give them, including at least 2 hours of full sun per day, and also regular watering, that is, moistening the soil as soon as it is dry to the touch. Average indoor temperatures suit them well and they won’t mind if you keep things cooler (but above freezing) in the winter. Fertilize from March to October with the fertilizer of your choice and if possible, put them outside for the summer.
Their one weak point is that they do appreciate humid air: it would be wise to increase the humidity in the winter to prevent leaf drop.
As your seedlings grow larger and larger, you’ll need to repot them into bigger pots. You may need to prune them too, especially if they begin to take up too much space. And be forewarned that several citrus plants are very thorny.
Pests to watch out for include red spiders and mealybugs. Treat them with insecticidal soap to bring them under control.
What About Flowers and Fruit?
Your little citrus seedlings are years from their first bloom. Even in the tropics, orange and lemon seedlings may take from 7 to 15 years before flowering for the first time. In the average home, where conditions are rarely perfect, you can easily add another 5 years to that. I know a lady whose 35-year-old lemon tree hasn’t yet bloomed… but she’s still hopeful!
Citrus growers rarely wait that long: they usually produce new citrus trees not from seed, but by grafting branches from a commercial variety onto a well-established rootstock recognized for its ability to stimulate early and abundant bloom. Since that isn’t possible indoors, you’ll have learn to cultivate patience.
And citrus also take up a lot of room, because most are medium-sized trees. Getting them to bloom indoors will therefore require a lot of indoor space.
For Impatient Gardeners
If you really want to see your citrus bloom (and the white flowers are so pleasantly scented!), growing them from seed is the wrong way to go. Instead, buy one that is already mature!
The calamondin orange (X Citrofortunella microcarpa, formerly known as X Citrofortunella mitis and Citrus mitis) is readily available in nurseries and blooms and fruits abundantly indoors. In addition, it’s a natural dwarf, easy to keep to 2 to 3 feet (60 to 90 cm) tall, and grows very well under indoor conditions. Its small orange fruits are also edible, though very bitter. They are mainly used in making marmalade.
For a few years now, citrus grafted onto dwarfing rootstock have been sold in garden centers as “patio plants” during the summer months and they’re often either in bloom or in fruit when you buy them. You can even choose your favorite kind: orange, lemon, grapefruit, etc. Just bring them indoors in the fall and continue to nurture them through the winter and they’ll be able to live and produce fruit for years.
Some nurseries, such as Flora Exotica in Canada and Logee’s and Top Tropicals in the United States. sell varieties of citrus more amenable to indoor growing than seed-grown varieties. Their plants are produced by cuttings or grafting and bloom quite readily.
Pollinate or Not?
If your citrus plant is flowering for the first time, it’s worth noting that many citrus are parthenogenic, that is, they’ll produce fruit without pollinization. However, others do normally require insect pollination… which they are unlikely to get if they bloom indoors. To pollinate them, you don’t even have to go from flower to flower, as they are self-fertile. Just stick a cotton swab into an open flower and twist it around a bit. That ought to transfer pollen from the stamens to the stigma and ensure fecundation.
Growing citrus from seeds: it’s a nice little project and one that you may well enjoy doing, especially with your kids or grandkids, but I suggest you not count your oranges before they ripen!