It’s a sad sight when a lemon tree doesn’t bloom or its flowers fall off before fruiting. So, how can you help your lemon tree bloom?
Lemon trees are self-pollinating and bloom year-round. However, they typically bloom in the fall and early spring. To bloom, they need sufficient sunlight, water, nutrients, pollination, and temperature. If your lemon tree isn’t blooming, it means it’s not getting the correct care or the tree is too young.
Let’s take a further look at how to get your lemon tree to bloom and what to expect.
When Do Lemon Trees Bloom?
Lemon trees need to mature before they start to bloom. Typically this means about 3-4 years of age. The exception to this is if they’re from a dwarf rootstock, in which case you could get fruit within as little as one year.
Once lemon trees are of age, they most commonly begin to bloom during spring. They are then typically ready to harvest in the fall.
Although, the blooming times are different with every tree. They have the possibility of blooming any time of the year if they are given the right conditions (we will go through these later).
Do Lemon Trees Self-Pollinate (Do You Need 2 Trees)?
Because they’re self-pollinating, lemon trees don’t need another tree or an outside pollinator. However, they still benefit from cross-pollination. When cross-pollinated, lemon trees have higher fruit counts and more yields.
By keeping multiple lemon trees close together, you increase the chances of pollination. This encourages pollinators such as bees, hummingbirds, and butterflies to transfer pollen from flower to flower.
Keep the 2 lemon trees no more than 50 feet away for the best chance of pollination.
If you’d like to still try to increase the pollination, you can take a clean, dry toothbrush and gently brush the blossoms to spread the pollen.
6 Reasons Lemon Trees Don’t Bloom
There can be several reasons why your lemon tree isn’t blooming. Most commonly, it’s due to the plant’s age. Although, a lack of water, sunlight, not enough pollination, or proper fertilization are key factors as well.
If your lemon tree is less than 3-4 years old, it might be too young to bloom and is still prioritizing leaf growth. There’s no way to force it to bloom at this point.
Consider waiting a bit longer to see if the tree matures enough to bloom. However, if it’s already matured past this window, then the lack of blossoms could be related to some other factors.
2. Improper Watering
Over-watering or under-watering can prevent your lemon tree from blossoming. Over-watering can drown the plant and cause root rot, while under-watering can signal to the plant to conserve water which pauses growth.
The goal for watering should be once every 1-2 weeks. The soil should be neither bone-dry nor sopping wet.
To know if you’re watering your tree enough, wait a week after watering and poke the soil with your finger and go 2-4 inches down.
If the soil is still wet from the previous week, then you’re either over-watering it or you’re not allowing for enough drainage. If this is the case, and it’s not draining, you might want to consider drilling holes in the bottom of the pot if it doesn’t already have them.
If the water has been sitting long enough, root rot could be taking place and the tree’s roots could be getting damaged. To tell if there’s root rot, dig a small corner of the soil and check to see how wet it is. If it’s still sopping wet and smells stale, you may need to repot it with new, uncollapsed soil.
If you’re in a hot climate and water is evaporating fast and drying the soil, consider using mulch-like leaves or straw to keep the moisture in and the soil shaded from the sun. If you’ve waited a week, and checked the soil by poking it with your finger and found it bone-dry, then you’re likely under-watering it.
There’s no one measure of water for any plant. It has to do for reasons such as container size, weather, soil drainage, and several other factors.
3. Lack of Sunlight and Warmth
Lemons are like most other citrus trees in that they need full sun. This amounts to at least 6 hours of sunlight a day. If you’ve placed your tree near a sunny window, it likely has enough sunlight to start producing blossoms. A southern-facing window works best as it often gets the longest amount of sunlight.
If you’re growing your tree indoors, and don’t get enough sunlight, then consider getting a full spectrum bulb and placing the plant no less than 12 inches away and no more than 12 hours a day.
Being a subtropical to tropical citrus tree, lemons need warmth to survive. Typically, they can survive in temperatures down to 20ºF (-6ºC), however, they prefer a temperature between 65-75ºF (18-23ºC).
To promote growth and blossoming, it’s best to consistently provide warmth for your lemon tree, although an occasional period of colder temperature, around 45ºF (7.2ºC), can help stimulate growth.
If there is a freeze in your area, you can cover the trunk of the lemon tree with bubble wrap or cardboard.
Whenever you’re helping your tree transition from different temperatures, it’s best to take it slow. Many plants are used to slower transitions from the seasons, so it’s best to mimic this process.
4. Not Enough Pollination
Yes, lemon trees are self-pollinating. But this doesn’t mean we can’t help. Cross-pollination leads to higher fruit yields and larger fruits.
The best way to increase pollination is to plant multiple lemon trees together.
If you’d like to manually pollination your lemon trees, take a clean, dry toothbrush or paintbrush and gently brush the blossoms to spread the pollen.
If your lemon tree is outside, you can plant companion plants near your lemon tree that attract outside pollinators such as bees or hummingbirds. These plants include wildflowers, lavender, comfrey, and more.
To learn about the best plants to increase pollination for your lemon tree or other citrus trees, check out my post on Companion Plants for Lemon Trees: Our Top 30 Picks
5. Improper Nutrients
Generally, fertilizing your lemon tree is a great idea, however, when you’re trying to increase the number of blossoms, it can do more harm than good.
Fertilizers high in nitrogen are great for promoting new leaf growth but can signal the tree to focus too much on foliage and not enough on the blossoms and fruit.
If this happens, then you might get little to no blossoming.
So, instead of fertilizers high in nitrogen, try fertilizers higher in phosphorus to help promote blossoming. Bone meal or fertilizers high in phosphorus can help promote blossom and fruit growth.
In general, try fertilizing your lemon tree once a month.
If your tree’s blossoms are falling off, you may want to hold off on the fertilizer and identify what could be causing it. If you suspect it is the fertilizer, you could try another brand and NPK combination, or get your soil tested.
For some great lemon tree fertilizers, check out my recent post: The Full Guide to Lemon Tree Fertilizer (& The Top 3 Brands).
6. Incorrect Pruning
Pruning is another vital aspect when it comes to the blossom rate of lemons. If you prune too much, you risk the tree not having enough resources to blossom and instead focus on foliage.
If you prune too little, then it can be overgrown and the many branches and leaves can expend a lot of the tree’s energy, and shade many leaves from sunlight.
The goal when pruning is to provide enough sunlight and air circulation to the tree’s branches and leaves. This will help keep mold and fungus from developing. It’s best to only prune when necessary.
Additionally, pruning properly will help the lemon tree grow the appropriate amount of fruit. Too much fruit production can lead to the tree not being able to provide enough resources and result in many small fruits. On the flip side, too little fruit production will result in meager harvests.
When pruning your lemon tree, keep the branches and shape of the tree wide and reaching out. If you have any branches that are growing more vertically, it can be best to trim these as they often don’t produce fruit. Prune branches at a 45º angle with the flat cut facing up.
If you have a potted lemon tree, it’s best to keep several clusters, or no more than 15 lemons developing at once for best results. If you have a planted and mature tree, you can keep several dozen developing fruit on it, and should be fine.
You can prune a lemon tree when it is nearing maturity and is healthy. This is usually in the first year or two. Be careful not to over prune and take out healthy branches.
There are also times to prune it when it’s not healthy, such as if some leaves are diseased or moldy, but in general, it can be best to let the tree reach full height (or near it) before starting to prune. Additionally, you can prune if the leaves are yellowing and dying.
Why Do Lemon Tree Blossoms Fall Off?
Blossoms begin to fall off when a lemon tree is either over, or under-watered, or lacks certain nutrients. The tree sheds the flowers to conserve energy and water consumption to increase the odds of survival. If this happens, consider checking your watering schedule or fertilizer.