Understanding the best way to care for your containerized Citrus Tree is essential to enjoying the lushest evergreen foliage, the most fragrant white blossoms, and of course, enjoying the juiciest, most flavorful fruit! Whether indoors or out, fertilizing your container Citrus should begin with some words of caution.
When Not To Fertilize:
Fertilizer should never be administered as a medicine to cure a poorly performing plant! When your tree is faltering, leaves are dropping or becoming yellowed, or the tree just isn’t performing well, slapping some fertilizer on it will do more harm than good!
While grown at the nursery, these plants receive consistent care, and this includes proper feeding. A properly cared for and regularly fertilized plant should never need additional fertilizing, nor does applying extra fertility ever cure poor performance.
Citrus are highly sensitive to changes in their environment. So, when one receives their new plant, typical symptoms that might arise from the adjustment to a new location include:
- Yellowing leaves
- Leaf wilt
- Leaf drop (both while still green and when yellowed)
- Flowers or immature fruit falling off
These symptoms rarely have anything to do with the plant’s nutrition! Adding fertilizer to roots and plants already struggling will cause them to spiral downward faster.
Most often these symptoms are the result of changes in the plant's environment. And sensitive plants like Citrus have a myriad of reasons to ‘freak out’, such as:
- Lower light levels - Been in a box a few days during shipping or when they’ve been brought indoors for the winter
- High light levels - not properly acclimated to a brighter or full sun environment
- Exposure to an excessively dry environment (drying out a bit during shipping)
- Overwatering and under watering
- Cold drafts or hot/dry air
- Drastic temperature changes
Your plants will initially experience some, or all, of these changes while shipping, despite our most careful attention to shipping them as fast and comfortably as possible. No one likes to be in a box for a couple of days, and sometimes it’s a bumpy ride. Northern gardeners, who bring their plants indoors for the winter or put them outside again in the spring, may also see some of these as after-effects if acclimation is not done gradually.
All care should be given to choosing the best location for your plant and learning how to develop the necessary watering habits that these trees need to thrive in their new environment before you’ve received them. Then plenty of patience while they get through their adjustment period.
Only after you have found a spot with consistent light and understand how to water, without overwatering, and your tree has acclimated to its new home, does the need for a consistent fertilizing program arise.
Citrus Fertilizing 101:
If you receive your plant in the fall, odds are that it has been specially fed at the nursery to support hardiness going into the winter. There should be no need for another application until later in the winter. If this is a new plant, you may consider removing any fruit that is forming so the plant can better focus all its energies on root development and acclimation to a new site.
A properly fertilized young Citrus tree is one that has diluted applications of organic fertilizer applied quarterly beginning in late winter. As the tree grows into larger containers the feeding becomes more frequent. Note that northern gardeners should skip the 4th application because they usually must bring their trees indoors for the winter and they will see little actual growth during those cold months.
Word of Caution: High Nitrogen fertilizers quite often affect the health of the soil and the growth of the tree by disturbing the soil biology. They are not recommended for container-grown Citrus trees.
Understanding Soil pH For Citrus Trees:
Citrus prefer slightly acidic soil, so it is best to use an acid-based fertilizer. These are fertilizers traditionally recommended for Azaleas, Camellias and Rhododendrons, however, there are also some specifically for Citrus trees too.
Your chosen Fertilizer should help maintain a healthy pH between 5.8 and 6.0 which is the ideal range suitable for Citrus, and a simple soil test kit can tell you your soil’s pH. Select a fertilizer that is preferably organic and slow-release.
Word of Caution: It is recommended that any fertilizers be applied by closely following the recommendations on the bag. Some like to use a dilute application and spread it over 3 or 4 quarterly applications for a nice slow release effect.
Citrus Soil:
Choosing amendments that maintain acidity in the soil will help maintain the right soil environment.
An acidic soil potting mix or additives consisting of shredded bark, Peat Moss, and Coir are always recommended for Citrus container plantings, plus this helps improve drainage that is also a vital component to Citrus root health.
To adjust the pH of the soil, try an application of Soil Sulfur or regular additions of Cottonseed Meal can help to maintain levels. Adding Nature Hills Root Booster also helps roots develop faster and helps with the exchange and breakdown of water and nutrients.
Citrus Watering & Humidity:
Another pH concern is to be aware that your tap water typically has a pH of 7 or above. Your water purveyor can provide your water’s pH, and you can collect rainwater for your indoor Citrus, which usually has a pH value of between 5.0 and 5.5.
Citrus love things on the drier side and soggy soil is a death sentence. A regular watering regimen is as important as fertilizing. Let plants dry out a bit to the touch before watering well, ensuring excess water drains out the bottom quickly, but not too quickly as when a plant has dried out too much. Use the Finger Test by poking a finger into the soil a couple of inches below the surface. If it feels damp under your fingernail or to the touch, wait a few days before checking and again. If it feels dry, water thoroughly.
Word of Caution: Always ensure container drainage holes are not plugged.
Air Humidity
Citrus prefer higher air humidity than soil moisture. Plants brought indoors for the winter can struggle when furnaces, space heaters and fireplaces tend to dry out the air significantly.
Try using a tray of pebbles beneath your plant to catch excess water and to fill with water, increasing ambient air humidity, or placing your tree by a humidifier. Misting your tree frequently helps as well!
Mulch
All container Citrus plants should be mulched. Adding a layer of Arborist bark chips to the soil surface has the same effect in a container that it does in the ground! It works to keep roots cool in hot weather, cuts down on evaporation, increases the time between watering, keeps weeds down and in time provides additional nutrient sources as it breaks down into organic matter.
Maintaining the mulch layer inside your container will also help to maintain the microbiology inside. Try not to disturb the mulch - but do add fresh mulch to the surface yearly or as needed. Try to maintain a 2-inch layer inside of the container.
Applying organic fertilizers to mulched containerized Citrus can pose a challenge as the fertilizer will rest and cake on top of your mulch. Make sure to distribute your fertilizer evenly around the surface in the pot and water in thoroughly until the fertilizer works down into your mulch.
Not Too Much, Not too Little…Just Right!
Growing Citrus in a container is a lot like raising fish in a fish tank. Everything is about balance!
The chemistry in the container-grown Citrus plant depends on you providing the food that supports the biology in the soil that feeds the plant's root system and in turn keeps your tree healthy.
As always, check with NatureHills.com and our team of horticulture experts any time you want more info! Let Nature Hills Nursery keep your Citrus trees happy and healthy so you can enjoy years of delicious fruit and their year-round ornamental beauty!
