Citrus trees are subtropical plants. They can survive temperatures of 28 degrees F for several hours without permanent damage. Most will not survive temperatures below 28 degrees F for any significant duration.
If you live in USDA Hardiness Zone 8, you may be able to, depending on your location and the variety you choose, plant your citrus tree outside. However, you will need to protect your tree from frost and freezing during extreme cold periods.
If you live in USDA Zone 7 or North, for survival of your tree, we strongly recommend you plant in a movable container which will allow you to move your citrus tree indoors during the winter. You can be as creative as you like in finding a pot for your tree. It can be decorative or just functional.
Planting in Ground
Planting in Containers – Choose a container that is 5 to 15 gallon size.
While some citrus varieties are cold tolerant, most citrus is not. Citrus is a sub-tropical plant. Regardless of where you live, it may be necessary to protect your tree during freezing conditions.
If the plant is still in a container, set the plant indoors if there is the possibility of a frost or freeze.
If a freeze is forecast, cover the tree with a sheet or blanket. Covering should be removed when outside temperature reaches 36 degrees or more. If several freezing nights are expected, you can build a “mini-greenhouse” out of PVC pipe around your tree and then cover with blankets or plastic. This would not have to be removed until cold weather was past. Just don’t let the covering touch the leaves.
Some leaf droppage can be expected following a freeze, but this should be a temporary situation.
NEVER prune the tree after a hard freeze until the new growth is well underway. If no new growth appears on the tree by late spring, the tree has sustained severe damage. Any new growth above the graft is new flush and is a good sign the tree has survived the freeze and should continue to produce. Any new growth below the graft (bud union) will be citrus rootstock and should be removed.
If you think your tree has a disease or other problem, contact your local county extension agent for a diagnosis.
Newly planted trees should be watered regularly for the first three months, if rains are inadequate. The soil should dry down between waterings.
For trees in containers, watering will need to be more frequent since tree isn’t planted in the ground. Let soil dry between watering. If tree stands in water, it will get root disease.
Fertilize every 3 – 4 months (November, March, June, August). Use a citrus fertilizer at a rate of 1 – 2 lbs. for every year of age. Fertilizer should be applied around drip line of tree. Do not put up next to the trunk. Slow release fertilizers work well and can be used less frequently; follow the instructions of the manufacturer.
Citrus trees require full sun year round. It is best to plant your tree such that it will get as much available sunlight as possible. If you live in a northern climate where you must move your tree indoors, try to place in a sunny location. Morning sun is the most beneficial for your tree. The south side of your house will usually provide the most sunlight.