Growing Citrus Trees Indoors


If you’re like me and you live somewhere where the weather is not always 75° and sunny (I’m looking at you, California!), then you may feel a little left out from the citrus tree trend that is gracing the backyards of those wonderful gardeners who live in growing zones 9-11. Here in growing zone 6, we have those humid and hot summers that citrus trees love, but are cursed with windy and icy winters that are not very citrus-friendly. Lucky for me, and for you, there is a solution: growing dwarf citrus trees indoors. But you came here to learn how to care for your citrus tree, so let’s get right to it.


What You Need

To grow citrus trees successfully, you’ll need patience, love, and a strong desire for freshly-squeezed lemonade (or orange juice, if you’re into that). You’ll also need:


  • One 20-gallon container with drainage (preferably a terra cotta pot) and a saucer

  • 2-1-1 fertilizer, heavy on the nitrogen

  • Loamy, acidic, well-draining soil

  • Pruning sheers

  • Of course, your choice of dwarf citrus tree


I recommend a terra cotta (clay) pot over anything, as they are durable and easily movable. Clay pots also give you a helping hand in regards to watering, but we’ll get to that in a bit.


Choosing Your Tree


The trickiest part of this whole process is deciding which type or types of citrus that you want to grow. There are so many different kinds out there for you to try, but here are my personal favorites:

  • Dwarf Improved Meyer Lemon

  • Dwarf Persian (Bearss) Lime

  • Dwarf Kumquat

  • Dwarf Satsuma Mandarin Tangerine (Orange)


If you’ve noticed, all of these varieties are dwarf trees. Personally, I think it would be very difficult to grow a full-sized tree in my apartment with 8-foot tall ceilings. Don’t be afraid though! Your dwarf tree can still grow up to 8 feet tall, or can be as small as 5 feet tall, depending on how you prune it.


In order to yield the best and most fruit, I recommend that you purchase a tree that is around 1-3 years old. While you can plant citrus trees from seeds, they are not exactly like their parent trees (very rebellious), and more often than not will not set fruit for you. Typically, a citrus tree sets fruit around ages 3-5 if given the proper care. Some citrus will flower in spring and summer, and set fruit all fall and winter; some citrus will flower and fruit all year long!


Head out to your local nursery or to an online nursery, where these dwarf trees are available all year long, and where they will certainly have the type of citrus tree you want. A 2-3 foot tall citrus tree can range in price from $15 to $80, and it is up to you to decide how much you want to spend on your tree. Purchasing a more expensive plant means that it will most likely be shipped without any damage to the plant, and typically will be from a better rootstock or more fruitful parent tree.


Planting Your Tree


Hooray! You’ve picked your tree! Now you must know that citrus trees are very particular when it comes to their wants and needs, and the list is extensive. Think of your citrus trees as very special houseguests that needs lots of attention, except that these houseguests will give you fruit!


When selecting a container to place your tree in, I suggest a 20-gallon terra cotta pot. The 20-gallon size will ensure that your tree is bottom-heavy, and the terra cotta is useful in telling if you are over-watering your citrus tree. Ensure that, whatever container you choose, your container has proper holes for draining, and a saucer to catch excess water. Before planting your citrus, it will be extremely helpful for you to put large pebbles into the bottom of your pot. Citrus trees do not do well with constant wetness near their roots, and these pebbles will keep your citrus happy by allowing the water near their roots to drain out rather than being stuck in the soil.


When determining what sort of soil to use for your citrus, keep in mind that it must be fast-draining and slightly acidic. You can either purchase a specialized avocado or citrus soil, or mix shredded (un-dyed) mulch with a loamy potting medium. Mixing the mulch with the soil will allow the water to flow more freely through the soil, allowing you to water your citrus deeply and infrequently.


When it comes to fertilizing your citrus, use one that is heavy in Nitrogen. I suggest a fertilizer that has a ratio of 2-1-1, used according to the directions on the package. Feed your tree monthly, and water deeply after each feeding. Failing to fertilize your tree is like letting your houseguest go hungry, and it won’t give you fruit with that kind of treatment!


Conditions


Now that your citrus tree is snug in its new home, it’s time to talk about the necessary conditions for citrus trees to thrive. While citrus trees have everything they need to survive outdoors in the spring and summer, when your citrus tree is inside during the fall and winter there are some things that you must provide it.


Sunlight

Citrus trees require 6-12 hours of sunlight every day, no more and no less. If your tree receives too little light, it will not flower. If your citrus receives too much light, it will become stressed and weak. Find the sunniest place in your space, which will most likely be near a south-facing window. If you do not have a spot that receives at least 6 hours of sunlight every day, citrus trees will still grow under artificial grow lights. However, I suggest finding a place that has at least a little bit of natural sunlight, as nothing can replace natural sun!


Temperature

Citrus trees thrive in temperatures between 55-80°F, with the perfect temperature being around 65°F. Citrus trees do not do well with quick temperature changes, and so should be kept away from any windows or vents that may cause the surrounding air to become cold or hot too quickly. However, citrus trees do enjoy air flow. If you find that there is a day in the fall or winter where it is a little warmer, open the window by your citrus tree to let it get a little fresh air.


Humidity

Along with the sun and the warmth, your citrus tree also needs lots of humidity–around 50%. If you do not have a humidifier, you can either spray your trees leaves with water every day, or place bowls of water near your radiator to get some more water into your air. I suggest misting your tree’s leaves with warm water, as this is the most direct way of ensuring that your citrus tree is humid enough.


Watering


The most important thing when it comes to watering your citrus tree is to use room-temperature water. Cold water and hot water will both harm your tree, rather than help it grow. As I mentioned before, citrus trees don’t do well when their roots are too wet. The best method of watering your citrus is to drown the soil, which involves watering infrequently but deeply. Only water your citrus tree when the soil is dry one inch from the top. With the proper rocks and soil in your pot, the water should run freely and drain extremely well. Because of this, you may want to place a one-gallon bucket underneath your citrus tree, as much of the water will flow out of the soil. Water your citrus until the soil is completely wet, which may take a minute or so. Water like so every 7 to 10 days in the winter, and up to 2 times per week in the heat of the summer. Citrus trees are very sensitive to both over and under-watering, and so it is important to know the signs of both.


Signs of over-watering:


  • Your clay pot is dark at the bottom, and water stays in the saucer

  • The soil is not drying in between waterings

  • The leaves are yellow, drooping, and wet




Signs of under-watering:

  • Water stays on the surface of the soil

  • The soil is dry deeper than one inch

  • The leaves are curled, drooping, and dry


Flowering & Setting Fruit


Congratulations! If you’ve reached the point where your tree has flowers, it means that you are giving your citrus the perfect care when it comes to warmth, light, water, and food. While your trees are indoors, they are missing out on one crucial step to get the flowers to set fruit, and that is pollination. Hopefully you don’t let bees and birds fly wild around your home, and if you don’t, that means you need to pollinate your flower by hand. You can do this with a pollinating tool, but personally I think it is just as easy to do with a cotton swab. Simply take pollen from one flower with the tip of your cotton swab, and gently place it on the stigma of the new flower. Repeat on whichever flowers you want to bear fruit, but remember that you don’t want to pollinate too many flowers, as this will result in your tree setting too much fruit for it to bear.

When your tree first sets fruit, it will overestimate itself, and set more fruit than it can bear. What you must do is thin out the fruit, or pick some of the fruit from the tree, even if it is not ripe. For your tree’s first time setting fruit, thin out the fruit until there are 4-6 pieces. When your tree begins to grow, thinning is not as important, and you can allow it to keep its fruit until it is ready to harvest. Remember to pick future fruit when it is ripe, because if fruit sits on the tree for too long, it can become flavorless and puffy!



Bugs & Disease


While all trees are at risk for attracting bugs and diseases, citrus trees are extremely vulnerable to both. All of that sweet-smelling fruit attracts fruit flies, spider mites, and scale. When the scale leaves honeydew on your citrus tree, this can attracts ants. It is important that you rid your tree of any insects immediately, and you can do so in a variety of ways. Most of the time, an infestation will cease if the tree is sprayed thoroughly with water. To play it safe, gently scrub each leave with dish soap, using a small sponge to remove all of the insects, spiderwebs, and honeydew. If your infestation is still taking over your citrus tree, you can use neem oil to spray on your tree, which is organic and safe to use to rid your tree of pests. The most important thing to remember when it comes to pests is that they won’t go away on their own, and that you should act quickly to save your produce.


Citrus trees that are grown indoors should not be prone to as many diseases as those grown outside, however there is always a risk of your citrus tree getting citrus black spot. You’ll probably recognize this as something you’ve seen on that lemon that you pass over at the grocery store, because it is very common for citrus trees that are not properly taken care of. Citrus black spot can be spread through spores in the air, a contaminated rootstock, unclean leaves, or even wet leaves that fall and become fertilizer for the tree. Once you see that your tree has black spot, sadly the only solution is to uproot it. Because this is a fungal disease, it takes over the whole plant, and any fruit that comes from the tree will have those dreaded black spots. But never fear! Citrus black spot is common only in outdoor trees that are subject to contamination, and the disease is primarily found in humid, moist, or tropical conditions, and is not as common in the upper U.S.


Check on Your Plant


One crucial step in raising and caring for your citrus tree is to listen to its needs. Your citrus can’t talk, but it can tell you what it needs if you check on it every day. Watch your citrus’s leaves, the soil, and the flowers or fruit to determine if you are caring for your citrus correctly. Wet, yellow leaves are a sign of over-watering, just as dry, yellow leaves are a sign of under-watering. Little bumps along the tree could be scale, and too much fruit on your tree means that it could grow weak. If you check up on your citrus every day, caring for its needs will be a lot less complicated than it sounds!



I hope you’ve enjoyed this blog, or have at least found it informational. I also hope that you are inspired to get out there and grow your citrus trees, because all of your hard work will be very fruitful! Tag us in pictures of your trees with the hashtag #PLGKC.

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8826 Santa Fe Drive Suite 300,

Overland Park, KS 66212

Tel: 913-362-0089

Bantes@plgkc.com

© 2017 Principal Landscape Group, LLC

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