Care of Dwarf Citrus Trees Indoor and Outdoor Container GrowingFew things are more beautiful in the dead of winter than the dark green leaves of a citrus tree. Because they are now available in dwarf sizes, gardeners in any climate can enjoy citrus trees. During cold weather, citrus trees can add beauty and fragrance indoors. Moving a tree from a patio to an indoor climate should be done gradually. Begin by placing the tree in partial shade. This helps it transition to less light. Even indoors, your tree will need at least 6 hours of sunlight a day. Grow lights can be purchased at your local hardware store and are a wise choice for safeguarding the health of indoor citrus. It's important not to overwater your citrus tree when it is indoors. See more on watering below.

Selecting Planting Containers We recommend a 6-9" container for our one year trees and a 10-14" container for our 2-3 year trees. A variety of decorative plastic containers are available at reasonable prices. Clay pots and wooden containers are very attractive but less mobile choices. When selecting a container, be sure there are sufficient drainage holes. Drilling extra holes is an easy way to improve drainage with wood or plastic. As the tree grows, increase the container size to a 16-20" diameter pot. Do not start with a pot that is too large as it makes soil moisture levels harder to control with small trees. Be sure your container drains freely, raising it off the ground if need be.

How to Plant in Containers We recommend using commercially available potting mixes. Avoid using unsterilized garden soil. Rose formulations can work, but the perfect high air filled porosity mix can be hard to find. If you can not find a mix without sphagnum peat moss, amend the soil mix with a 1/4- 1/3 volume of 1" redwood shavings. Our 2-3 year trees are shipped with shavings suitable for potting mix amendments. Cedar shavings can be used as well, but avoid pine and spruce. Once your soil mix is prepared, the container is selected and the tree's eventual location is known you are ready to begin potting.

Place one inch of soil in the bottom of your new container. Gently remove the roots and soil from the old container. Try to keep the root ball intact. Place the root ball in the new container and fill with your fresh potting mix. The top of the roots should be just barely beneath the top of the soil level. Loosely tie tree to a stake if needed. Press the soil around the root ball to provide stability and water deeply. Loosely tie tree to a stake. Repotting with fresh soil mix every year or two will provide fresh nutrients to the soil.

Selecting a Location for Outdoor Containers

Sunny, wind free locations with southern exposure are the best. If in doubt, leave the tree in its plastic container and place it in the spot you have in mind. After a week or two, you should be able to tell whether or not it is thriving. Reflected heat from sidewalks or houses can also help to create a warmer microclimate. Avoid lawns that get frequent, shallow watering.

Watering

Consistency is the key with citrus watering. Citrus trees require soil that is moist but never soggy. Watering frequency will vary with soil porosity, tree size, and environmental factors. DO NOT WATER IF THE TOP OF THE SOIL IS DRY WITHOUT CHECKING THE SOIL AT ROOT LEVEL! A simple moisture meter, available at garden supply stores, will read moisture at the root level. This inexpensive tool will allow you to never have to guess about whether or not a plant needs water. A wilted tree that perks up within 24 hours after watering indicates the roots got too dry. Adjust watering schedule accordingly. A tree with yellow or leaves, or leaves that don't look perky AFTER watering can indicate excessive watering and soggy roots. Give your tree water less often. Citrus prefer infrequent, deep watering to frequent, shallow sprinklings. Creating a watering basin around the tree's drip line can aid in deep watering. Deeper watering promotes deeper root growth and strengthens your tree. Generally, once or twice a week deep watering works well for container specimens. Be sure to adjust based on weather conditions! In general, it is probably best to water in the morning, but if plants are dry or wilted it is better to water them right away than wait until morning.

Fertilizer

Citrus trees feed heavily on nitrogen. Your fertilizer should have more nitrogen (N) than phosphorous (P) or potassium (K). Use at least a 2-1-1 ratio. Miracid Soil Acidifier is a water-soluble product that works well and is a 3-1-1 ratio. In some regions, you may be able to find specialized citrus/avocado fertilizers. Buy a good brand and apply according to package directions.

Also important are trace minerals like iron, zinc, and manganese, so make sure those are included as well. Many all-purpose products will work. We prefer slow release fertilizers in the granular form rather than fertilizer stakes. Follow rates on the package carefully as fertilizers come in different strengths, release rates, and application schedules. We recommend that you fertilize more often than recommended with most slow release fertilizers. Foliar applications of trace minerals in the form of kelp or other soluble fertilizers can be effective on leaves when half their mature size. Yellowing leaves indicate lack of fertilizer or poor drainage.

Suckering

Know where the graft union is on your tree. It can usually be seen as a diagonal scar between 4 and 8 inches from the soil. Remove all shoot growth below the graft. These so-called "suckers" take vitality from the top of the tree (the fruiting wood). Especially on young trees, they are very vigorous. Remove suckers as soon as they are observed.

Thorns

Thorns are removed from rootstocks when they are grafted. Juvenile fruiting wood will sometimes have thorns; this is a young plant's way of defending against grazing animals. As the tree matures, thorns will not appear as often. Prune off thorns if desired. Check thorny branches to see if they are fruiting wood or rootstock.

Pruning

Citrus may be pruned to any desired shape. Pruning is fine any time of year, except in the winter for outdoor trees. Pinching back tips of new growth is the best way to round out the trees without impacting future fruit. Citrus will look fuller with occasional pruning to shape leggy branches. Some trees may develop erratic juvenile growth above the graft. If so, prune for shape and balance. Any growth above the graft can eventually bear fruit. Do not be afraid to cut off branches. It will stimulate growth and multiple branches from the site you pruned. Well-pruned trees have higher fruit yields and are less prone to branch breakage.

Pollination

Most citrus are self-pollinating, even indoors. Some people enjoy pollinating their trees and can do so by using a small soft brush or cotton swab to transfer pollen among the flowers.

Citrus can be trained to grow on trellises. Simply use green garden ties to hold branches in place and prune to encourage desired branching patterns.

Beneficial Insects

Most insects do no harm to citrus trees! Spiders, lady beetles, lacewings, and preying mantids (praying mantis) are some of the beneficial insects you may see around citrus trees outdoors. You can even buy some of these predator insects in local nurseries for release in your garden.

Pest Insects

Keep your tree free of ants. They will farm scales or aphids, moving them from place to place, milking their secretions, and protecting them from beneficial insects. Ant baits may be helpful.

If you find harmful insects like scales, aphids, or mites, a household spray bottle of water with some mild dish soap could be all you need. If insects persist, the usual nursery treatment is a 1% solution of light horticultural oil.

Frost

Even temperate locations can drop below freezing, so it's good to have a plan in mind for that eventuality. Christmas lights strung around your tree will provide some protection, as will an antitranspirant like Cloud Cover. A frost blanket, loosely draped over and around the tree, will also help. Or, you can overwinter your tree indoors. Home