My parents have an orange tree in their backyard, and recently, it started to get brown leaves. I was concerned its health was declining, so I did some research to help find out what could be going wrong. Here’s what I found causes brown leaves on orange trees.
Orange trees get brown leaves from over or under-watering, extreme temperatures, or an excess of nutrients. Typically, watering and weather are more common causes, but high levels of fertilizer can cause the issue. For best results, water only when the top 2-4 inches of soil are dry and fertilize as suggested.
So, while orange trees can get brown leaves from several causes, how do you know which issue is causing it, and how do you fix it? Let’s take a closer look.
Over and Under-Watering
Watering orange trees improperly can quickly lead to brown leaves. Under-watering orange trees can cause drought stress, especially in times of hot weather, while over-watering can drown the roots. Generally, only water the tree when the top 2-4 inches of soil are dry and apply compost and mulch.
Orange trees require a lot of water to grow and fruit properly (how else are they going to get juicy fruits?). Brown leaves can occur on orange trees due to their leaves drying out from a lack of water or from the stress of over-watering.
However, every orange tree requires a different amount of water, so getting it right can be tricky.
So, what’s the best way to water orange trees?
As a general rule, only water orange trees when the top 2-4 inches of soil gets dry. You can check this by pushing a finger into the soil, up to the second knuckle. If the soil is sopping wet 1 or more hours after watering, the soil likely needs more drainage.
Sometimes over-watering isn’t caused by too much water, but by poor soil drainage. In this case, follow these tips to help provide more drainage for your orange trees:
- Planted orange trees can have their soil’s drainage amended by adding sand and compost or by relocating the tree to an elevated area, such as a mound or raised bed. By elevating the soil from the rest of the ground, you’re letting gravity assist with the drainage.
- Potted orange trees can either have more drainage holes installed or have their soil repotted with fresh, well-draining soil as needed.
If you’re looking for good potting soil to use for your orange trees, you can check out my recent post: Create Amazing Homemade Potting Soil for Your Citrus Tree.
In either case, avoid relocating or repotting orange trees unless it is necessary. Sometimes transplant shock can occur and create more stress and damage to the tree.
On the other hand, if you find that your orange tree’s soil is under-watered and is drying out too quickly, compost and mulch are great practices.
Compost not only provides amazing nutrients for your orange tree (often removing the need for fertilizer), but it drastically improves the water retention of the soil. Every 1% increase in the soil’s richness can hold an additional 20,000 gallons of water per acre.
Mulch greatly reduces evaporation from the soil, allowing it to stay moist longer. This helps keep the soil and roots cool in hot and dry weather. Mulching also prevents soil erosion and protects the beneficial soil bacteria. Some good mulches for orange trees are leaves, bark, grass clippings, straw, and pine needles.
So, if you’re finding that your orange tree’s soil is drying out quickly, add 2 inches of each compost and mulch to the top of the soil, under the canopy. Just make sure to keep them at least 3 inches away from the tree’s trunk to prevent mold or disease from spreading.
Composting and mulching are extremely beneficial practices that should be used on just about any plant. However, if the soil has poor drainage, make sure to address this first.
If you live in a dry or cold climate, it may be causing your orange tree to get brown leaves. In this case, your orange tree may need shelter from the weather. Orange trees are native to the tropics, so they prefer hot and humid weather. Normally, when they’re in this climate, they’re fairly self-sufficient.
While some orange tree varieties are hardier than others, they generally do best in temperatures ranging from 35ºF to 100ºF and in USDA hardiness zones 9-11. This typically means little to no frost.
Additionally, orange and other citrus trees don’t do the best in extremely dry climates such as those in New Mexico, Arizona, and Nevada. The citrus trees that tend to normally do well in these areas have some help and are well-watered.
For example, here in Austin, Texas, I have a potted lemon tree. While we get decent rainfall, we occasionally get a winter storm with quite a bit of snow and frost. Luckily, I can bring my lemon tree indoors during the winter. However, if it was left outside, it would have most likely started to die, first developing brown and falling leaves.
So, make sure to check your USDA hardiness zone and average rainfall before you grow orange trees outdoors.
However, keep in mind that some zones can be stretched to an extent.
Here are some tips to care for orange trees in colder climates:
- Plant orange trees in a southern-facing direction for the maximum amount of sunlight and warmth. Additionally, you can plant them along a southern-facing wall to reflect light and heat onto the tree, even into the night.
- Insulate orange trees with sheets or cardboard in times of frost. While this won’t prevent all of the effects of frost, it will greatly reduce them.
- Avoid watering at night since the water can freeze on the leaves. For best results, water in the early morning. This not only avoids the frost but prevents the hot afternoon sun from blistering the wet leaves.
And here are some tips to grow orange trees in drier climates:
- Composting and mulching are a MUST for orange trees growing in drier areas. This will dramatically reduce the amount of water you’ll need to provide the tree and encourages the tree to grow deeper roots, helping it access deeper water tables.
- Provide a few hours of afternoon shade for orange trees to give them a break from the heat. This is especially useful in temperatures above 100ºF. You can create shade by using umbrellas, shade sails, or other trees. The morning sun is typically the coolest, so provide as much light as possible during this time.
While it’s not as common, orange trees can get brown leaves from having too many nutrients available in the soil. These nutrients can chemically burn the tree’s roots, leading to the tree’s leaves browning and dropping. For best results, use a slow-release fertilizer or quality compost. A good NPK to use is 6-3-3.
Orange trees are heavy feeders, so they require more nutrients than some other fruiting trees. Typically, they prefer double the nitrogen to phosphorus and potassium (commonly abbreviated as NPK). However, by using a fast-release fertilizer or by providing too much, the tree can become stressed and start to die.
Generally, orange trees should be fertilized with a slow-release chemical fertilizer 1-2 times per year or compost every 1-2 months.
If you believe your orange tree has been over-fertilized, hold off on fertilizing and water generously over the next month. The water will help dilute and leach the excess nutrients from the soil. Just make sure not to over-water your orange tree (you can follow the watering recommendations in the section above).
If you’d like a recommendation for good orange tree fertilizers, you can check out my recommended orange tree fertilizers.
Alternatively, you can use compost.
While compost isn’t as potent as fertilizers, it can remove the need for them by providing everything the orange tree needs. For best results, provide 2 inches of compost on top of the soil every 1-2 months. As mentioned before, keep the compost at least 3 inches from the tree’s trunk.
Compost also has other benefits such as improving water retention in the soil and supporting beneficial soil life—which in turn provides orange trees with nutrients located past the reach of their roots.
In some cases, soil life such as mycorrhizal fungi can also improve the tree’s disease resistance and even help trees warn other trees of pests and disease.
But, even though nutrients are important, they’re not everything.
Orange trees also require a balanced soil pH. Without the proper pH, orange trees will be unable to absorb nutrients from the soil.
The best soil pH for orange trees is a slightly acidic pH of 6.0-7.0.
For example, soils that are high in clay typically have a more alkaline pH (along with poor drainage), while soils high in sand are more acidic and have better drainage.
If you aren’t sure how to measure your soil’s pH, you can use pH strips or a pH meter. I personally prefer using a pH meter since it’s affordable and easy to use. To see which pH meter I use and recommend, you can visit my recommended tools page.
More Tips to Care for Orange Trees
- Orange trees are evergreen trees, so they’re not supposed to lose their leaves in the autumn like deciduous trees. Because of this, if you see more than 10% of the leaves curling, yellowing, browning, or falling off, inspect your tree and its soil for any issues. If its leaves are spotted, it likely indicates a disease.
- Repot potted orange trees into a larger container every 3-5 years. If not repotted, orange trees can become rootbound become stressed. This can cause issues with the leaves, fruit, and function of the tree.
- Orange trees don’t need to be pruned, but they can help train the tree to either grow faster or fruit more. For orange trees under 3 years old, you can prune any flowers or fruit to help the tree redirect its nutrients to grow foliage and reach a mature size faster. For orange trees older than 3 years, prune excess foliage to encourage maximum fruiting.