Lemon tree yellowing leaves

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Causes of yellow leaves on citrus trees

Citrus trees are versatile and do well in most climates, but there are lots of things that can give your lemon tree problems! Here are the conditions that can turn your lush greens to sour yellows:

  • Changes in weather
  • Too much or too little water
  • Lack of nutrients
  • Pests or parasites
  • Root rot
  • Sunburn
  • Citrus diseases

How to care for lemon trees with yellow leaves

With preventive measures, you’ll get a healthy harvest with tons of yellow lemons instead of yellow leaves. Just follow our top tips for proper lemon tree care!

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Balance temperature

Drastic seasonal changes can give your citrus yellow leaves and stress them out! Lemon trees thrive during summer, but if there’s too much heat they can become dehydrated. Also, if it’s too cold in the winter the leaves can become brittle and damaged from the frost. So depending on the climate you can try to balance the temperature accordingly by either providing shade or removing it when you see leaves curling.

Just add water

Do you know how often to water your lemon tree? Follow these watering tips and schedules, so they never experience a draught or a drowning:

  • Freshly planted – water every other day during its first week of life. For the next two months, water once or twice a week during dry spells.
  • Planted for two years – during the first two years of its life, lemon trees need water every five days.
  • Mature plant – water older plants between seven to fourteen days during the dry season.

Diagnose deficiencies

Listen to your lemons! Just like humans, your plants need a nutritious diet. Using good fertiliser helps provide the essential nutrients for optimum growth. Here’s a list of deficiencies, how to identify them, and ways to treat them:

  • Nitrogen deficiency – shows as yellowing of older leaves in the tree’s foliage. You can add special nitrogen-boosted fertiliser in your feeding to help resolve it.
  • Zinc or iron deficiency – shows as yellowing of new leaves with green veins. To fix this, use a kelp spray solution or add zinc to the soil bed.
  • Magnesium deficiency – shows as light green or yellow blotches on leaves. To treat this, dissolve a teaspoon of Epsom salts in half a gallon of water and pour into the soil evenly.

The soil is the foundation where your citrus tree’s roots will expand and grow. It’s important that it has the right PH levels to maintain great health. If you’re concerned, you can get soil test kits to figure out what your plant needs!

Pest control

A pest or parasite infestation is one of the toughest issues to deal with as a gardener. Besides sucking the nutrients from the leaves, the little critters can wreak havoc and give your lemon tree diseases. There are many types of insects, pests and parasites that love lemons, including:

  • Aphids
  • Rust mites
  • Spider mites
  • Leafroller moths
  • Mealybugs
  • Cutworms
  • Scale insects
  • Whiteflies

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When giving your plants a layer of protection, always go with the natural route. Using chemicals can negatively affect your fruit and turn your soil toxic, which caused even more problems. Instead, make a homemade spray with organic elements to protect your plant from pesky bugs. You can use Neem and Jojoba oil directly, but you can also make special sprays with these ingredients:

  • Dormant oil – mix a tablespoon of baking soda with two tablespoons of canola oil in a gallon of water.
  • Horticultural oil – mix five tablespoons of hydrogen peroxide, two tablespoons of baking soda, and two tablespoons of olive oil soap in a gallon of water.

Spray your chosen mixture onto all the leaves and branches of your lemon trees. Try to get as much coverage as possible since some bugs won’t fall off unless you fully cover them in slippery oil! These will also prevent the spread of sooty mould and powdery mildew.

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Proper drainage

Stagnant water trapped inside the soil can cause root rot. If your plants are in pots, make sure there are enough holes for proper water drainage. Rotting can also occur when the roots outgrow the size of their containers. If your lemon tree is getting too big for its pot, give it more room by transferring it to a bigger one!

Prune and trim

Citrus trees enjoy regular pruning to increase airflow, photosynthesis, and growth. Methods like topping and skirting can help prevent bugs from climbing onto the tree. If left unpruned, your tree will be more prone to the spread of diseases from the soil and other contaminated leaves.

Throw shade

Lemon trees love the sun, but there is such a thing as too much of it. Excessive sun exposure can cause the leaves to gradually bleach and fade. Shield your plants from sunburn by giving them shade when it’s too hot outside. Some farmers use the whitewashing method to act as a sunscreen by painting white latex on the bark of the tree.

If you see yellow, don’t panic!

Stay mellow the next time you see yellow! It may seem concerning at first, but everything should be fine. The lightening of leaves just functions as a warning sign that your lemon tree needs a bit of extra support! Just remember to follow our pro-tips and you’ll be back to seeing green in no time!

RELATED: 6 alternative uses for lemons

You could have a few things going on. If the leaves are a washed out uniform yellow color, the tree could need to be fed or you may have an issue with water.
The nitrogen in fertilizer (the first number) is used by the plant to produce the green color of the leaves. If your plant is nitrogen deficient, the leaves will begin to yellow. The solution is to feed your plant.
Citrus plants will want ample water, but will want to dry out between watering. Give them a good soak, and then let them dry out before the next application of water. You will want the soil near the roots to dry out, not just the surface of the soil. If you’re unsure, you can pick up an inexpensive water meter that has a long probe that can reach below the soil surface to tell you what’s going on near the roots. If you’re giving them too much water or water too often, the solution to the yellow leaves is to back off the water. Water them on their schedule, not yours.

If the leaves are a washed out yellow color with dark green veins, that’s usually a symptom of iron deficiency. Citrus are high iron feeders. Organic fertilizers do not contain iron. Because iron is a mineral, it’s not considered “organic”. For this reason when using organic fertilizers, we recommend a supplemental feeding of Iron. We make two products for this purpose. Our Greenall FST is a granular Iron, Sulfur, Zinc and Manganese product. You will want to apply twice a year. Once in early spring and again in the late summer or early fall. The other product is our Greenall Liquid Chelated Iron.
The liquid Chelated Iron, will work faster than the FST, but because it’s in a liquid form, will probably need to be use more often to keep the nice green color.
Our Greenall Citrus and Avocado Food, our traditional synthetic fertilizer, does contain Iron and other trace minerals, but you may still need a supplemental feeding of Iron occasionally.

Yellowing leaves on citrus trees spell trouble | San Luis Obispo Tribune

Bright green leaves sheltering colorful hanging fruit distinguish healthy citrus trees. Yellow leaves, on the other hand, spell trouble.

Causes are numerous, but often relate to improper irrigation and nutrient deficiencies. Other culprits include pests, bacteria, fungi and phytotoxicity caused by a variety of herbicides, fungicides and salt burn.

Water: As evergreens, citrus may require irrigation year-round to ensure good soil moisture to a depth of about 2 feet for mature trees. Conditions that are too wet or too dry can reduce the tree’s ability to take up nutrients, especially nitrogen.

Very dry rootzones, an impact of the ongoing drought, have led to more nitrogen deficiencies seen in citrus. At the same time, it’s important to ensure good drainage, since water-logged roots cannot adequately absorb soil nutrients. If you see a tree canopy of pale green-to-yellow leaves, check your soil moisture in the top two feet before applying fertilizers.

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Allow the top 6 inches of soil to dry between watering, typically ranging from 7-to-14 days depending on weather and soil conditions. For this reason, citrus trees should not be planted in lawns or near heavily irrigated plants. Also ensure you have good soil moisture on the deep end of the rootzone so that roots can take up available nutrients.

Fertilizer: Citrus trees require regular doses of nitrogen, zinc, manganese, magnesium and iron to remain healthy and productive. Two or three applications of a slow-release citrus formula annually should do the trick. If you only manage a single dose per year, apply in early spring before flowering and fruit setting when nutrient demand is highest.

Mulches: A nutrient-rich mulch of yard waste consisting of wood chips, grass clippings and leaves can also be beneficial for citrus trees, according to the University of California. The high nitrogen in grass clippings offsets the high carbon of the wood chips, and the combination has been shown to be effective in suppressing Phytophthora root rot when present in the soil.

Also be sure to keep mulches at least 6 inches from tree trunks to discourage fungi and bacterial growth on trunk and roots.

Resources: Visit UC-IPM website for colored pictures and detailed descriptions of common diseases and deficiencies that negatively affect citrus trees: http://www.ipm.ucdavis.edu/PMG/C107/m107bpleaftwigdis.html

Leslie E. Stevens is a UCCE Master Gardener.

Got a gardening question?

In San Luis Obispo call 781-5939, Arroyo Grande, 473-7190 and Templeton, 434-4105. Visit us at http://ucanr.org/sites/mgslo/ or email us at [email protected] Follow us on Instagram at slo_mgs and like us on Facebook. Informative garden workshops are held the third Saturday of every month, 10 a.m. to noon at 2156 Sierra Way, San Luis Obispo. Garden docents are available after the workshop until 1 p.m. To request a tour of the garden, call 781-5939.

Why are my lemon tree leaves turning yellow?

Lemons and other citrus trees need specific nutrients to be productive and healthy.

Q. Why are my lemon tree leaves turning yellow?

A. Leaf yellowing in lemons and other citrus is a common problem for gardeners. Citrus are gross feeders – if your plant’s leaves are yellowing or it’s cropping poorly, lack of nutrients could be to blame.The different yellow discolouration patterns can be used to diagnose what’s wrong with the plant. Here’s what to do for some common symptoms.

1. Leaves are yellow all over
When older leaves are yellow all over it’s a sign of magnesium deficiency. This nutrient deficiency doesn’t necessarily mean a lack of magnesium in the soil. The soil may be too alkaline so the magnesium is not in a form that can be taken up by the tree roots. A quick fix is to apply Sequestron or Yellow Leaf Remedy (from garden centres) or Epsom salts. Mix Epsom salts in water for a foliar spray (20gm per litre) or apply to the soil (about 20gm per metre of tree height) and water in well. Don’t overdo it – especially in containers where a build-up of magnesium can be as harmful as a deficit. As a longer term fix feed every six weeks with a citrus-specific fertiliser from spring to autumn.

* How to deal with common winter citrus problems
* Oranges and lemons – how to make your citrus spectacular
* Gardening guru Lynda Hallinan’s citrus marmalade tips

2. Yellowish leaves in winter
Leaves with yellow tones over winter can be a natural process. Kate Marshall from Waimea Nurseries says most citrus trees are grafted onto Trifoliata or Flying Dragon rootstocks, which are deciduous on their own. Therefore when used as a rootstock in winter the roots stop taking up nutrition, leaving the evergreen part of the tree hungry for food. Margined or mottled yellow leaves are a symptom of nutrient deficiency. Kate recommends waiting until spring to feed with general citrus fertiliser, as the deciduous rootstocks won’t take up any food during the winter months. Fertilising citrus in the cooler months can be tricky, as it is best to avoid encouraging a flush of tender new growth that could easily get frosted or cold damaged. Instead feed with Dolomite lime and gypsum, which will increase trace element nutrition and improve leaf appearance without stimulating a flush.

3. New leaves are pale yellow, pale green or white with green veins
This is a sign of iron deficiency due to the soil being too alkaline, so the iron is not in a form available for root uptake. Apply iron chelates (from garden centres) to the foliage as a liquid feed or drench the soil with Sequestron. Zinc deficiency has similar symptoms but in this case the young leaves are small, narrow and distorted as well as being pale. Zinc is leached out of sandy, light soils and alkaline conditions make it unavailable to plants. Apply a trace element mix, Sequestron or citrus fertiliser.

4. Leaves are dehydrated and yellow
Look under the leaves for minute insects called mites. Mite infestations are common in dry, hot weather. Use a soap-based spray. Cover both upper and lower leaf surfaces with spray to ensure good control. Apply in the morning or early evening when temperatures are cooler. Keep a close eye on the tree and repeat spray at 10-12 day intervals if mites reappear. Water citrus trees in dry weather.

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Yellow Lemon Tree Foliage – Why Did Lemon Tree Leaves Turn Yellow

When life gives you lemons, you make lemonade – and lots of it if you own a lemon tree! But do you know what to do when the lemonade stops flowing because your tree has developed yellow leaves? Yellow lemon tree foliage can indicate a number of correctable problems, but if you’re attentive, the lemon juice will soon be flowing again.

Yellow Leaves on a Lemon Tree

Often, lemon tree leaves turn yellow when the plant is experiencing some kind of major change in nutritional intake. This might mean that the plant has a parasite or it could indicate a need for improved feeding techniques. Here are a few of the most common reasons your lemon leaves are turning yellow:

Seasonal changes

Many lemons today are grafted onto deciduous rootstocks, meaning that they’ll be forced by their hosts to hibernate through the winter. When the rootstock starts to go into winter slowdown, it reduces the flow of nutrients to the leaves, causing them to yellow and fall. Don’t worry, this is a natural occurrence and doesn’t mean anything is wrong with your plant.

Sometimes, yellow leaves appear after placing a lemon tree outside in the spring or summer, or after a particularly sunny day. If the leaves are suddenly yellow to white in patches, it means sunburn is likely. As long as there are other healthy leaves remaining, it’s nothing to worry about. Leave the affected leaves in place.

Overwatering

There are few things that are so universally despised by plants than overwatering. When plants that aren’t native to bogs, like lemons, are constantly left soaking in water, their roots can rot – sometimes entirely. When this happens, it’s hard for the plant to continue to pull nutrients from the soil, so it slowly starts to yellow and dry up.

If you routinely leave your lemon plant in a saucer full of water or the drainage around your tree isn’t great, dig around the roots to check their health. White, solid roots mean things are just fine; brown, black or slimy roots mean root rot is the culprit. Repot your tree into dry soil mixed for citrus and a pot that drains quickly. Water it regularly until the roots grow back (remembering to empty any excess water collects in saucers), then you can give it a mild fertilizer to jump start new leaf growth.

Nutritional deficiencies

Lemons are heavy feeders and sometimes they’re just not getting enough of the good stuff. Pale leaves can indicate deficiencies in iron, zinc, nitrogen or magnesium. Test the soil in the root zone of your lemon tree, then make the necessary adjustments. Sometimes a plant spike made for citrus trees is all you need. Sometimes the nutrients are there, but unavailable due to problems with the pH. This usually will require a stronger remedy specific to the problem.

Insect parasites

Lemons are beloved by humans, but insects and mites like them, too. Sap-sucking insects can cause damage enough to leaves that they develop yellow spots that eventually grow together to form large yellow patches. Check the undersides of the leaves and stems for the specific parasite involved.

Aphids and whiteflies can easily be sprayed off with regular garden hose blasts; scale and mealybugs (which often have waxy coatings) may need chemical treatment or horticultural oil, depending on the season. Mites, which are technically arachnids and not insects, are easily dispatched with a soap-based miticide.

Why are the Leaves on Your Lemon Tree Turning Yellow?

Why are the leaves on your lemon trees turning yellow? Two common causes are chlorosis, or iron deficiency, and nitrogen deficiency. Here is how to tell the difference.

Chlorosis. Chlorosis is an iron deficiency that appears as lightening or yellowing between veins on older leaves and/or pale green or yellow new leaves. Affected leaves will never return to normal because iron is not a mobile nutrient, meaning that it cannot be relocated within a plant. Alkaline city water and alkaline soils are common causes of chlorosis; iron becomes decreasingly available to trees when soil pH is above 6.0, and is mostly unavailable at pH of 7.0 and above. Chlorosis in citrus is often chronic due to naturally alkaline soils combined with watering over years with alkaline city water. Trees may also become chlorotic as a result of wet or waterlogged soils, anaerobic soils, root rot diseases, or damaged roots. Applying chelated iron will improve chlorosis temporarily, but is not a long-term solution or cure; further, chelated iron may rapidly become unavailable in alkaline soils.

GardenZeus recommends one or both of the following solutions. First, encourage a thriving, healthy soil ecosystem that will naturally improve soil pH. Second, increase soil pH by mulching with face-down cut halves of waste citrus, watering with a diluted vinegar solution of 1/4 to 1/2 cup of white vinegar in 2 gallons of water, or using an acidifying product such as pH Reducer.

Nitrogen Deficiency. In contrast to chlorosis, nitrogen deficiency appears as pale or yellowing older leaves accompanied by green and healthy new growth. Unlike iron, nitrogen is a mobile nutrient; that is, plants have the ability to move nitrogen from older leaves to produce new growth. A nitrogen-deficient lemon tree has healthy green leaves and pale or yellowing older leaves appearing simultaneously.

GardenZeus recommends the following for nitrogen deficiency: Apply a nitrogen soil drench in the form of diluted urea or chicken manure at the rate of one cup of chicken manure per four 4 gallons of water (half cup if fresh manure), mix thoroughly, and apply near the driplines of trees a few times per year. Fresh or composted manures may be applied as a surface-dressing under mulch. Adding too much nitrogen to soils may result in lush, high-carbohydrate leaves that attract insect infestation, and may delay or reduce fruit formation if added too early in the fruiting cycle.

GardenZeus has customized gardening information by plant and zip code. Don’t know your GardenZeus zone?

Don’t know your soil pH? The following articles may be of interest:

Mud Pies and Fizz: Easy Home Tests for Soil pH

Tips for Testing Soil at Home with a Soil pH Meter

Yellowing Leaves on Citrus Trees

Hi and welcome fellow Citrus growers!

One of the questions I often receive is “Why are the Leaves Yellow” on my Citrus Tree? More often, specifically on the Meyer Lemon Tree which is the most the most popular of all Indoor Citrus trees.
We will address what causes the leaves to turn yellow and the specific remedies to correct this common issue.

Reason #1: NATURAL SHEDDING AND LEAF DROP:

It is common for the leaves at the bottom of the tree or in the interior that are not receiving much sunlight to naturally turn yellow and drop. If you only have a few yellow leaves in those locations then that is natural and part of the trees normal leaf shedding process and poses no concern.

Reason #2: EXTENSIVE YELLOW LEAVES THROUGHOUT THE TREE WITH LEAF DROP:

This is normally caused by an overwatering situation and/or poor drainage. When the roots sit in soggy soil they will begin to rot and they will lost their ability to carry nutrients up to the canopy of the tree. You may need to change your pot out with good drainage holes and if you re-pot make sure the potting soil you use is lightweight and does NOT contain wetting agents. Secondly, amend your watering and fertilizing as noted below to get your plant on a healthy path (It will take several months to correct this issue, be patient).

Reason #3: YELLOW AND MOTTLED GREEN LEAVES THROUGHOUT THE TREE:

This is an indication that your plant needs some food. I recommend you feed your plant at least every (3) months but to really give your a plant a “POP” feed monthly starting in March all the way through November. Proper plant food and watering coupled with sunshine will help your plant thrive and aid in its blossoming/fruit production.

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. It is better for the soil to be on the dryer side when you water.

A wilted tree that perks up within 24 hours after watering indicates the roots got too dry. Adjust the watering schedule accordingly. A tree with yellow or cupped 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. 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 (For example; a 15-6 -8 or 12-4-5 or 18 – 8-10 would work well … remember you do not have to be exact, just try to find one that the first number is about twice as high as the other numbers). 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. Osmocote slow release plant food is another good fertilizer.

Any good citrus formula will contain trace minerals like iron, zinc, and manganese. Many all-purpose products will work. Just add trace mineral supplements if your fertilizer is deficient. We prefer slow release fertilizers in the granular form rather than fertilizer stakes. Follow the instructions 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.

Check out our Video Tutorials that cover many of these same issues by clicking here.

Wishing you great success with your Citrus Growing!

George

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