Growing Citrus In Containers

This last winter I was sitting in my kitchen talking to my niece, Rachel, about her upcoming birthday. I asked her what present she would like for her birthday. Without hesitation she said, “That orange tree!”

Behind me was a Calamondin orange tree loaded with bright 2-inch diameter fruit and growing in a beautiful Italian clay pot. She has good taste and an eye for plants.

Fortunately, I was able to gracefully negotiate my way out of sending her home that night with my Calamondin orange. I promised her that in the spring I would find her one and put it in a beautiful pot just like mine. So this spring I did track down another plant just for her.

Citrus plants are not cold-hardy in Kentucky so we cannot plant them in the ground, but this doesn’t mean we can’t grow them at all. In fact, they are quite easy to grow in containers. They love our sunny, hot, and humid summers. Kentucky’s late spring and summers are perfect for citrus fruit production. Many citrus plants, especially grapefruit, need a good hot summer for the fruit to develop to full size, color, and sweetness.

Calamondin orange
The Calamondin orange appears to be a cross between a kumquat and a mandarin. The plants are much smaller than traditional citrus plants and grow only 3 to 4 feet tall. The leaves are simple and smooth with a good traditional to dark green color. The flowers are small and white but abundant and very fragrant.

The fruits are typically 1 to 2 inches in diameter and round. Once fruits are developed, they remain green for several months before they ripen to a nice bright orange. Once ripe they can remain on the plant for quite some time.

I have fruits on my Calamondin that have been orange for more than 4 months. It is easy to leave the fruit on even when they look perfectly ripe, because it just takes one bite and you won’t try that again. The Calamondin orange’s fruit is quite bitter and I speak from experience.

Oranges are one of the few fruits that will not continue to ripen once they are picked. They can also remain on the plant when ripe for some time without becoming overripe and losing their sweetness or tartness, whichever the case may be.

While citrus plants are not winter-hardy, they are cold-tolerant and can take temperatures in the low 30s without much problem when fruit is not present. The fruit is much less cold-tolerant and, when on the plant, should be protected from frost. I usually take my Calamondin orange outside in mid-April and don’t bring it inside until well into October.

Planting your citrus
When choosing a container, pick a heavy one that is a bit wider than tall when possible—this will help prevent it from blowing over when you have it outside. Water generously outside where it is freely draining. Once inside for the winter, make sure to let the top 3 to 4 inches dry before watering and never let water sit in the saucer for more than 30 minutes.

You can also choose a heavier planting mix, or make your own with a combination of ProMix and worm castings or a complete landscape mix. If you have chosen a container without a drain hole, make sure to drill one in it before planting.

Container-grown citrus plants should be fertilized regularly from April to August. If you can find a specialty fertilizer for citrus, that’s best, but they are hard to find outside of the native citrus range. I like to fertilize once a month with a good blended fertilizer with micronutrients. If you can’t find one to suit both needs, select a good 20-20-20 and something like Monty’s Joy Juice or Espoma’s Hollytone and alternate the 20-20-20 and the liquid fertilizer each month.

When you bring your citrus plants in for the winter, place them in the sunniest window possible or supplement with a grow light.

Blooming cycle
Most citrus plants bloom traditionally in the winter or early spring, but there are several, like my Calamondin orange, that will bloom and fruit year-round. The Calamondin typically has ripe fruit on it when it begins to bloom again. There are quite a few citrus varieties besides the Calamondin orange that make great houseplants even though many bloom only once a year.

If you have a citrus that requires pollination to set fruit and it’s blooming inside in the winter, you will have to transfer the pollen from flower to flower with a small paintbrush. This isn’t as hard as it sounds, but you can check the Web for more information. Out of curiosity, I did a quick Web search for growing citrus, and many of the best sites I found were in Europe where growing citrus in containers is as common as growing tomatoes in Kentucky.

Have a gardening question?
Go online to www.KentuckyLiving.com, click on Home & Garden on the left, and then on “Ask The Gardener” link.