Lemon tree seedlings. Photo: depositphotos
By Larry Hodgson
You can fill your house with beautiful foliage plants for next to nothing by sowing the seeds found inside fruits you buy at the grocery store. Citrus, avocados, pomegranates, kiwis, papayas, coffee plants, lychees, date palms, pomegranates, dragon fruit cactus, guavas and more can all make interesting houseplants.
Ideally, you’d choose a fruit of tropical or subtropical origin. Fruits from temperate climates—apples, grapes, cherries, etc.—produce seeds which sometimes germinate well, but rarely succeed indoors over the long term. They really need the distinct seasonal changes of a temperate climate to thrive, not the constant warmth of indoors.
It’s also vital that the fruit you buy contains fertile seeds. Bananas, navel oranges*, most figs and several other tropical fruits are sterile and either bear no seeds or their seeds aren’t viable. Also, the fruit must not have been cooked, irradiated or otherwise treated in a way that could prevent germination. Store-bought dates, for example, have usually been irradiated. There is a better chance of finding fruits with viable seeds in a market specializing in organic produce than in a regular supermarket.
*Navel oranges, although theoretically seedless, do occasionally produce a viable seed or two.
Green Plants, Not Fruiting Ones
Do note that most fruit seeds will produce only “foliage plants”: there is little chance of these plants ever flowering and fruiting under indoor conditions. And if they do, you’ll have to be very patient. Citrus, for example, will flower and produce fruit indoors, but rarely in less than 10 to 15 years. The coffee plant (Coffea arabica) is an exception. If you can find a fresh coffee berry rather the usual roasted (and therefore dead) bean, you can harvest and sow the bean inside and your little coffee plant could be bearing fruit in as little as 3 or 4 years.
How to Sow Tropical Fruit Seeds Indoors
Ideally, you’d start your seeds indoors in the spring or summer, seasons when the light is plentiful and atmospheric humidity is excellent. However, you can do so even in the winter under a LED or fluorescent grow light, perhaps with the help of a heat mat to ensure beneficial heat, as it can be quite cool on a windowsill at that season and cool temperatures hinder germination.
Harvest the seeds from the fruit and wash them in water to remove any flesh. There’s no need to dry the seeds out before sowing them, although you often see that useless bit of information on the Internet. In several cases, drying the seeds before planting can slow down germination or even prevent it.
Fill a pot or tray with slightly moist potting or seedling soil mix to about 1 in (2 cm) from the top. Dig a few holes about 3 times deeper than the seed is high into the mix and drop a seed into each one. Cover it with potting mix. (For large seeds, like the avocado, you only need to bury the bottom half only of the seed, not the whole thing*.) Now water lightly, just enough to settle the soil a bit.
*You can also get an avocado seed to sprout over a glass of water. Read Growing an Avocado Indoors for more details.
Cover the pot with a clear plastic dome or bag or some other type of mini greenhouse to maintain high humidity and a more constant temperature, two conditions necessary for good germination. Expose this mini-greenhouse to warm conditions—70 to 80 ˚F/ 21 to 27 ° C—and moderate lighting. No need for direct sun yet, however: not as long as the pot is inside its mini-greenhouse; otherwise it can overheat.
Germination can take anywhere from 2 weeks to 3 or 4 months. Normally, no watering will be necessary as long as the pot is “under glass” (inside its clear plastic shelter), but if the potting soil begins to appear dry, turning pale brown, add a spoon or two of water.
When green shoots appear, that means germination has occurred. Wait 2 or 3 weeks more, then start acclimatizing the seedlings to indoor conditions. To do so, gradually open the mini greenhouse over a week or two so the plants can become used to the drier atmosphere outside. After germination, there is no longer any need to keep the pot warm either: regular room temperatures are now quite acceptable. Only when the mini greenhouse has been completely removed, however, should you expose the seedlings to direct sunlight.
If there are several seedlings in the pot, this is also a good time to pot them up individually if that is the way you intend to grow them.
From now on, what was a seedling is now a houseplant in its own right and it will need intense light, normal indoor temperatures, good humidity, regular watering as soon as the soil feels dry to the touch, a bit of fertilizer every now and then and other aspects of basic houseplant care. This will give you a beautiful foliage plant that will grow little by little … and who knows? Maybe after a decade or two, you just might get some fruit!