The top reasons why lemon trees grow flowers but not fruit include lack of water during Spring and Summer, receiving less than 6 hours of sunlight, not enough potassium, lack of pollination, a tree aged less than 2 years or extreme weather conditions.
Here are the top 6 causes of flowers not developing into fruit on your lemon tree and how to solve each one.
6 Reasons why lemon trees have flowers but no fruit
Check out the top reasons why lemon trees have flowers that don’t develop into fruit.
1. Not getting enough water in spring and summer
If the tree dries out during spring and summer when the flowers are forming it can drop flowers or young fruit. Check the amount of moisture in the soil every 2 days during spring and summer. Place your finger 1-2 inches below the surface of the soil and if it feels dry, water your lemon tree deeply with your garden hose.
Set a watering schedule for your lemon tree. Check it 3 times per week and deep water outdoor trees.
Pre-fill a watering can inside so you can easily water indoor plants. Add a small amount of liquid fruiting fertilizer to the watering can to top up the nutrients as you water.
Add a 2-3 inch layer of bark chip mulch under outdoor trees to keep soil moisture in for longer
2. Getting less than 6 hours of sunlight
Lemon trees will grow flowers but may not form fruit if they are not getting at least 6 hours of sunlight during the day. Lemon trees that are growing in shade are less likely to be pollinated by nearby insects.
Potted lemon trees can be moved into a sunnier position if the flowers are not forming into fruit.
Before you plant your lemon tree out into your garden use annuals to see which areas get the most sun. Plant bright flowering annuals like violas around your garden and see which ones flower best. This will give you a good idea about which areas of your garden get the most sun and will be the best spot for your lemon tree.
3. Not enough potassium
Lemon trees that lack potassium will not develop fruit from their flowers. This is a key nutrient needed by the plant to form and grow fruit.
Give your lemon tree a citrus fertilizer or sulfate of potash to increase the potassium to nitrogen content. Potassium is needed by your lemon tree to form flowers and fruit. This help your plant to set fruit instead of dropping flowers.
Higher nitrogen fertilizers are great for getting your plant established in its first year in your garden. Once it has settled in the ground increase the potassium levels to encourage it to set fruit.
Check out this quick video for top reasons why citrus trees drop flowers.
4. Lack of flower pollination
When lemon flowers are not pollinated they will not form fruit. Lemon outdoor lemon trees will be pollinated by insects or the wind. If they are in a sheltered spot or if there are few pollinating insects around they may not form fruit.
Indoor lemon trees will need to be hand pollinated to get the flowers to turn into fruit. Use a small paint brush to transfer pollen from flower to flower. Outdoor lemon trees can be fertilized by insects or the wind.
Plant your garden with a variety of flowering plants to attract bees. Lavender is a great companion to lemon trees as it flowers well at the same time as your lemon. This will attract more pollinating insects to your garden to help your lemon tree to grow fruit.
5. The lemon tree is too young
A lemon tree that is less than 2-3 years old may produce flowers but will not grow fruit. The best way is to encourage the lemon tree to grow fruit is to allow the first year for it to settle in and grow more stems and leaves. Plant the tree in soil with added compost, aged cow manure and pelleted chicken manure.
Water your lemon tree well during the warm weather and add an extra handful of pelleted chicken manure in Spring and Fall. This will help your lemon tree to establish quickly.
Lemon trees that have been grafted or are more advanced will usually then produce fruit in the next season after they have settled into the ground.
Choose a more advanced lemon tree if you are keen to get fruit as soon as possible.
6. Extreme weather conditions
Weather conditions like extreme heat over summer can cause your lemon tree to drop flowers instead of growing fruit. Very cold spring weather and frosts can stop your lemon tree fruit fruiting.
Outdoor trees can be protected from frosts by laying a thick layer of mulch over the root zone and placing a cover over the tree branches at night to keep frosts off the leaves and stems. Watching the weather predictions can help you to know when the next frosts are likely and you can protect your trees.
Remove any covers placed over your plant the next day after the sun comes up and this can help your tree to keep its fruit.
Lemon tree flowers but no fruit – summary
Lemon trees thrive on regular water and lots of nutrients. Protecting your lemon tree root system with a layer of compost and tree mulch will help the feeder roots to absorb the nutrients they need to grow flowers and fruit. You will soon be rewarded with delicious lemons.
I am an accredited practicing dietitian, experienced gardener and a dedicated cook. I love writing and sharing my experience so you can learn from my successes and mistakes.