Growing Citrus Indoors Under LED Lights: Lemons, Limes and Oranges

Citrus trees can live happily indoors through winter if they get enough light. University extension advice is at least 6 hours of direct sun a day and preferably 8 to 12 hours, which is more than most windows give from November to February. An LED grow light on a timer for 8 to 12 hours makes up the difference.

Why citrus needs help indoors

Perhaps you want to grow an orange or another citrus tree that cannot be grown outside year-round because of colder temperatures. The usual answer is a large pot that can be moved indoors for winter. The problem is light. Citrus are sun-lovers. The University of Maryland Extension advises that citrus need at least six hours of direct sun a day, preferably eight to twelve, and a south-facing window gives the strongest winter light. Even then, short winter days and low sun often fall short. A grow light puts back the light that the season takes away. For other people who use grow lights, see who would use an LED grow light.

Citrus that suit indoor growing

Choose dwarf or compact types that tolerate containers:

Meyer lemon, a favorite because it fruits well in pots and is more tolerant of cool, indoor conditions.
Calamondin, a small, tough, ornamental citrus with tiny sour fruit.
Kumquat, with edible skin and a compact habit.
Key lime and other dwarf limes, which like warmth and strong light.
Dwarf oranges and mandarins, such as dwarf satsuma and clementine types.

Grafted dwarf trees from a reputable nursery usually fruit sooner than seed-grown plants.

How much light does citrus need?

Extension sources give guidance as hours of sun, not as grow light settings. Treat the figures below as a practical conversion rather than a rule:

Window only: a south-facing window may deliver the six or more hours of direct sun that citrus wants in autumn and spring, but often not in winter.
Window plus supplement: if the tree gets fewer than about six hours of direct light, add a grow light. Grower guides commonly suggest 8 to 12 hours of supplemental light a day, and some growers go as high as 12 to 16.
No window: in a tent or a room without sun, the light has to do everything, so use a strong LED and a longer day.

Citrus also benefit from a rest, so keep a dark period and use a timer. Because citrus are a high-light crop, pick a strong full-spectrum fixture and size it to the canopy. See how many LED grow lights you need and how many hours of light plants need.

Setting up the light

Use full-spectrum white light. It supports healthy growth and shows leaf color honestly. See full spectrum LED grow lights.
Hang the light above the canopy and angle it to cover the sides if you can. Follow the maker's height guidance. See how far to hang LED grow lights from plants.
Put the light on a timer.
Raise the light as the tree grows, and rotate the pot each week so all sides get light.

A grow tent with a My LED Grow Lights light is a neat way to house citrus trees until spring arrives. It is also a great alternative if you do not have a sunny spot indoors, or if you need to keep your plants out of reach of pets and young children. See grow tent lighting setup.

Move plants gradually

A sudden change in light and temperature makes citrus drop leaves. When bringing a tree indoors for winter, do it before nights get cold and over a week or two:

Spray it and check it for pests first.
Move it to a shadier spot outdoors for a few days.
Then bring it inside, in a bright place or under the light.

Do the same in reverse in spring, and harden the tree off outdoors before putting it in full sun.

Temperature, humidity and watering

Temperature: citrus like a comfortable room, and many tolerate cooler nights. Keep trees away from cold drafts and heating vents.
Humidity: indoor air in winter is dry. A tray of pebbles and water or a humidifier helps.
Watering: water thoroughly when the top inch or two of soil is dry, and never leave the pot sitting in water.
Container: use a pot with drainage and a well-draining potting mix.

Feeding

Citrus are hungry plants. Use a fertilizer made for citrus, with micronutrients, and follow the label. Many growers feed less in winter when growth slows and more through spring and summer.

Pollination indoors

Citrus flowers have a strong scent and are mostly self-fertile, but indoors there are no bees or wind. To set fruit, move pollen by hand: gently dab the center of each open flower with a small, soft brush, moving from flower to flower, or shake the branches lightly. A fan helps too.

Common problems and fixes

Problem	Likely cause	Fix
Leaves dropping after the move indoors	Sudden change in light and temperature	Give bright light on a timer; be patient; avoid further moves
Yellow leaves	Overwatering, poor drainage or low nutrients	Check drainage; water less; feed with a citrus fertilizer
Flowers drop without fruit	No pollination, dry air or low light	Pollinate by hand; raise humidity; check light hours
Sticky leaves, tiny insects or webbing	Scale, whiteflies or spider mites	Inspect often; wipe leaves; use insecticidal soap
Long, pale new growth	Too little light	Lower the light or raise the dimmer; lengthen the day

How long until you get fruit?

Citrus are slow. A grafted dwarf tree may flower within a year or two of purchase, and fruit takes many months to ripen after the flowers are pollinated, often most of a year for lemons and oranges. Seed-grown trees take longer, often many years. Patience pays: a healthy dwarf citrus can crop for years.

Repotting and soil

Repot into a pot only slightly larger when roots fill the container, usually every two to three years.
Use a well-draining mix made for citrus or for containers, and avoid heavy garden soil.
Choose a pot with drainage holes, and empty the saucer after watering.

The winter rest and the return outdoors

Many citrus growers keep trees in a cooler, bright spot over winter, water less and feed less, then return the tree to its full routine in spring. When nights are reliably warm, move the tree outdoors gradually: start in shade, increase sun over a week or two and keep it out of strong wind. Bring it indoors again before the first cold nights, and repeat the gradual change.

Questions about citrus under LED lights

Can I grow citrus entirely under a grow light?

Yes, in a tent or a room without sun, if the light is strong and the day is long enough. It is the highest-light plant in this guide.

Why is my citrus dropping leaves?

Often it is a sudden change of light, temperature or watering. Keep conditions steady and check the drainage.

How close should the light be?

Follow the maker's chart for your fixture and watch the leaves. See how far to hang LED grow lights from plants.

Key takeaways

Citrus need at least 6 hours of direct sun, and preferably 8 to 12, so winter indoors usually needs a grow light.
Choose dwarf varieties such as Meyer lemon, calamondin and kumquat.
Move trees gradually between outdoors and indoors to avoid leaf drop.
Pollinate by hand indoors, and keep humidity up and drainage good.
Fruit takes many months, so be patient.

Why LED lights suit citrus

A citrus tree needs strong light for many hours a day through winter, so efficiency matters. My LED Grow Lights use roughly half the power of traditional HID's, run on 120v or 240v and include a dimmer switch. See all of our LED grow lights, or return to what to grow under LED lights.

Growing Citrus Indoors Under LED Lights