Why is My Kumquat Tree Dropping Fruit (And How To Fix It)

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Is your kumquat tree dropping fruit and would you like to know why and how to fix it? You’ve come to the right place! We’ll be looking at the possible reasons why a kumquat tree drops fruit and some solutions to fix the problem.

Generally, the reasons a kumquat tree drops fruit include natural fruit drop, inconsistent watering, lack of nutrients, change in weather, or attack by pest or disease.

Why is My Kumquat Tree Dropping Fruit (And How To Fix It)

Growing kumquats can be immensely rewarding. There is nothing like the feeling you get from picking your first fruit of the season. So it is disheartening and frustrating when the little green jewels of potential kumquat fruit start to fall from the tree before they’ve begun to ripen.  So let’s look more closely at why your kumquat tree would drop its fruit and how to fix it.  

Natural Kumquat Fruit Drop

Why is My Kumquat Tree Dropping Fruit And How To Fix It

All fruit trees drop some of their fruit at various stages of development. This ensures that the tree can cope with ripening the amount of fruit remaining.  If the previous season has yielded a bumper crop of kumquats, a greater percentage of fruit is likely to drop this season.

Many commercial fruit growers manually force a percentage of fruit to drop to ensure an even yield over the years. So, if some kumquat fruit is dropping, this is normal and not a cause for concern.

Inconsistent Watering of Kumquat Tree

The most common reason for kumquat fruit to fall prematurely from trees is to do with the amount of water they receive. Drought conditions with too little water, will stress the kumquat tree and cause it to drop its fruit in its struggle to survive.  

At the same time, too much water can cause a kumquat tree to drop its fruit.  Overwatering, especially of kumquat trees in pots, can cause the nutrients to leach from the soil and the tree becomes starved and drops fruit.

Kumquats like a slow deep watering every 3-7 days in hot dry weather and every 7-14 days in cold, wet weather. Small trees need to be watered more often than large trees as their root systems are not as fully developed.

Why is My Kumquat Tree Dropping Fruit (And How To Fix It) - Kumquat Tree

Trees in pots should be watered every other day in hot weather and twice a week in cool weather.  Water enough to ensure water is reaching the bottom of the pot. Nutrients will be washed out with running water but this just means you will have to top up the fertilizer more regularly.

Overwatering of trees in soil with poor drainage can lead to brown rot or root rot, which will cause fruit to drop. This is caused by a fungus on the roots. The fungus thrives in damp conditions so allowing the soil to dry off will help combat the fungus. This is particularly common in trees in pots where the drainage may not be ideal or watering every day may lead to roots never getting a chance to dry off.

Lack of Nutrients for Kumquat Tree

Lack of nutrients is a common cause of fruit drop. For example, a lack of phosphorous is a common problem and usually results in the tree not flowering but can also cause fruit drop. Phosphorous is vitally important to plants and is almost impossible to overdose as it is difficult to absorb. A good place to start would be to provide phosphorous. Giving your kumquat tree a good feed of compost can help it to absorb the phosphorous that is already present in the soil. If you feel the kumquat tree needs more phosphorous try giving it bone meal which is high in phosphorous and natural.

Low potassium can cause fruit drop. Organic sources of potassium are crab waste, burned cucumber skins, kelp, banana peels, wood ash, and greensand (available here). Simply dig some of these into the soil around your tree before watering and the potassium will leach into the soil and be absorbed by your kumquat tree.

Kumquat trees, like other citrus trees, use a lot of nitrogen. A shortage of nitrogen during the growing period can cause fruit to drop. Alfalfa meal, animal manure and compost are all excellent, organic sources of nitrogen.

Kumquat trees generally need to be fertilized 3 times a year with a citrus fertilizer. Do this at the start of every season except winter. This makes it easy to remember and helps keep your kumquat tree happy and healthy.

Change in Weather can Cause Kumquat Tree Fruit Drop

Why is My Kumquat Tree Dropping Fruit And How To Fix It - holding a dropped kumquat

A sudden or drastic change in weather can cause a kumquat tree to stress and drop its fruit. Heavy frosts will cause all fruits of a certain stage to fall. The older a kumquat tree is, the more resistant to frost it will be. If your Kumquat tree is young it is a good idea to cover it during the coldest months. There are a variety of frost protection covers available.

Sudden high temperatures soon after the fruit set can also cause fruit to drop.

Disease and Pests and Cause Kumquat Tree Fruit Drop

Often a pest infestation, such as mites, can cause fruit to drop but this usually occurs late in the growing season.  

Citrus greening is a bacterium spread by aphid-like psyllids. It is characterized by yellowing in one section of the tree. This will cause leaves and fruit to drop and can cause fruit to be small, lopsided, and bitter.

The black citrus aphid attacks fruit while it is very small and causes it to drop. Sprays should be used with caution as they will not only kill the aphids but often result in killing good insects as well.

If you are wanting to keep your garden completely organic a natural predator such as lacewings or ladybugs can be introduced to take care of your aphid infestation. Organic insecticidal soaps and horticultural neem oil can be used to combat black citrus aphids.  

Neem Oil Spray

Neem oil can be used in this simple home spray recipe to combat aphids and other garden pests.

½ an ounce of neem oil

1 teaspoon natural liquid soap

2 quarts of warm water

Place these 3 ingredients into a spray bottle and spray onto your infected kumquat tree. It will not affect the edibleness of your fruit but it is always a good idea to rinse fruit before eating.

Garlic Bug Spray

Alternatively, you could mix your own organic aphid spray. This garlic bug spray is ideal as it repels aphids without killing any good insects like ladybirds.  

1 head garlic

1 onion

½ cup vegetable oil

1 teaspoon cayenne pepper

1 tablespoon liquid soap

1 quart water

Puree the garlic, onion, and water in a food processor and allow it to sit overnight. Strain the garlic mixture and add oil, cayenne pepper, and soap. Dilute the mixture 1 cup garlic bug spray to one-quart water. Spray it onto your infected kumquat tree. Spray every week for effective control of aphids.

Conclusion

Try to use a process of elimination to determine which of the above reasons may be the cause of your kumquat tree dropping its fruit. The most common is watering issues so start there. Adjust your watering routine and monitor your tree. Trees are always happy to receive a dose of phosphorus, potassium, and nitrogen so giving some of these can only be beneficial.  Lastly, look for signs of pests and try to eradicate them. You should have your kumquat tree healthy and bearing delicious fruit in no time.

Further reading:

Why is My Kumquat Tree Dropping Fruit and Fixing it