Lemon trees can be grown easily indoors in pots and containers. Depending on the available area, common lemon trees can be trimmed to desired size or one can grow dwarf varieties, which can be the size of bonsai tree and fit even windowsill.
Growing lemon trees indoors in containers protect lemon trees from winter cold and strong winds and enables a grower to enjoy these decorative plants year long. Of course, for indoors, one has to choose varieties which flower and bear fruits year long.
Soil mix - soil mix for indoor lemon tree should be mix of good potting soil and organic matter like compost and humus. One can add hydroton pebbles to improve water holding capacity, which is very important when growing plants during summer heat. Remember that lemons require moisture, but they don't like 'wet feet'! Soil must have good drainage and pH around 6.0 and 6.5. Before planting the lemon tree, check if the tree is growing on its own roots or if it is grafted.
Dwarf varieties are commonly grafted on dwarfing rootstock, with graft union some 2-8 inches (5-20 cm) above the soil top - depending on the used plants and desired plant size.
Amount of soil varies depending on the planned tree size and ranges from just few liters to few gallons. Larger containers, which are suitable for growing 'common' lemon trees, are much larger - for example 24 inches (60 cm) in diameter and 20 inches tall containers have volume of ~140 liters (37 gallons) when fully filled with the soil and should be positioned on the cart with wheels for easier transportation inside and outside.
Watering lemon trees in containers must be done regularly, especially during summer months, when plants growing outside must be watered on almost daily basis. If the lemon trees are kept inside year long, water according the room temperature. Since waterlogged soil must be avoided, don't use too much water - if there is excess water in the container tray, decrease the amount of water.
Fertilization is very important, since lemon trees indoors are grown for their fragrant fruits, but also for decorative purposes. If you have just few dwarf lemon trees, the most simplest solution is to use liquid fertilizers for citrus fruits enriched with various microelements - just add required amount of fertilizer when watering the plants and your plants will be happy. Of course, this is not the cheapest solution.
Pollination of lemon trees in containers - when lemon trees are kept outside, one doesn't have to worry about pollination - bees and other insects like lemon flowers and will do their job well.
However, when lemon trees are inside, one must pollinate the flowers. The best and easiest way to do it, is to take small, soft paint brush to transfer pollen to the stigma. It takes just few seconds for each flower and achieve very good result. Using 'high-tech' air pumps and similar tools maybe (just maybe!) produces better results, but why bother ... IMHO, of course!
Sun exposure - lemons prefer full sun positions, so grow them near large windows facing south (or north, if you live in southern hemisphere). To improve health of the plants, artificial lightning can be used to increase the light intensity and daily light period - aim for at least 12, but not more than 18 hours of light.
Note: lemons will grow happily next to the large window with 7-8 hours of daily light, but will grow slower than with 12-16 hours of sunlight. To promote uniform growth, rotate plant's side facing the window every few days.
Temperature range - lemons prefer warmer areas, but will grow on room temperatures well. Acceptable temperature range is between 70 and 100 degrees Fahrenheit (21 to 38°C) with the best temperature around 85 degrees Fahrenheit (29-30°C). Above 105 degrees (40°C) lemon tree will stop to grow, while below 50 degrees (10°C) lemon tree will go into the dormancy. Temperatures below 30 degrees Fahrenheit (-1°C) can cause plant to drop the leaves, while prolonged exposure to such low temperatures will damage the fruits and the tree, killing it in the end.
Long story short - lemon trees are easily grown in containers, inside and outside. Dwarf lemon trees can be very decorative plants bearing full size lemon fruits.
If you like lemons, give them a try, you will not regret.