Growing Citrus Indoors

Many years ago, I enjoyed a grapefruit grown by my mother-in-law in Fallbrook, California. Inside was a sprouted seed. I took it as a sign that I should grow a grapefruit tree. That tree is still alive after more than two decades, and has six grapefruit growing on it. I was so excited once it began to produce that I added a lemon tree to my citrus collection. It’s now covered with ripe lemons and starting to bloom again.

Reality check:  the trees live indoors, of course, and I have a large sunroom big enough to contain them, with some careful pruning. Citrus can’t grow outdoors year-round in northern Nevada because our winters are too cold. But, with some help, lemons, grapefruit and other types of citrus will survive and even thrive.

Citrus plants are available at a few local nurseries, or you can special-order them. While I got lucky with my grapefruit tree, it’s not actually the best idea to grow them from seed. It can take ten years or longer to produce fruit. And, many commercial trees have a hardy rootstock that doesn’t produce quality fruit grafted with a different tree that produces better tasting fruit. Seeds rarely grow fruit similar to the parent and the fruit may be unappealing.

If you want to try growing citrus, start with good soil as a foundation. Citrus needs well-drained acidic soil. When transplanting a tree, use a container with holes in the bottom and a high-quality potting soil mix. If root-bound, loosen or lightly prune the roots before planting. Set the pot on a saucer filled with pebbles to aid in drainage.

One of the surest ways to kill or damage your plant is by overwatering. Keep soil moist but not wet. Stick your finger into the top inch or two of soil before you water the plant. It should feel moderately dry. Soak thoroughly, but don’t let water sit in the saucer after watering.

Citrus needs lots of direct sunlight, ideally 10 to 12 hours a day. If you don’t have a spot that gets at least five hours of direct sunlight, your citrus will struggle. Temperature is less of an issue. Citrus tolerates heat well (after all, it grows in Florida!) but tends to stop growing at temperatures less than 55 degrees F.

I especially enjoy the lovely fragrance of the blooms. While most varieties are self-pollinating, I do individually pollinate the blooms using a cotton swab to collect and move the pollen so that I ensure a good crop.

Pollination is not enough, though. It takes nutrients to grow the fruit. Apply fertilizers during spring and summer. Use a product for acid-loving plants that is high in nitrogen and moderate in phosphorus and potassium. Citrus is prone to micronutrient deficiencies, especially iron, manganese and zinc. If you see yellowing of the leaves but the veins stay green, and you are not overwatering or allowing water to remain in the saucer, it may be due to a micronutrient deficiency. Try adding chelated iron according to the label directions. The chelated form improves absorption.

If you’re successful and your tree produces fruit, leave it on the tree to ripen before you pick it. Enjoy!