How to Fertilize a Lemon Tree

As a first-time lemon tree grower with only modest experience growing a handful of other house plants and annual vegetables, the concept of fertilizing was initially a complete mystery to me. “Do I need to fertilize? When should I fertilize? How often should I fertilize? What type of fertilizer should I use?” Those were all questions running through my mind when I took my first lemon tree into my care, and was determined to see it thrive.

Fortunately, there are plenty of resources available and several guidelines to follow that can help your figure out if your lemon tree needs fertilization, and exactly how to do that.

I did comprehensive research while figuring out how to fertilize my own lemon tree, and have compiled the following information to help you take the best care of your lemon tree. Using fertilizer can help ensure that your lemon tree is happy, healthy, and producing an abundance of juicy, tart fruit for years to come. Read on to find out more.

Do I need to fertilize my lemon tree?

Yes! The answer is yes, you should fertilize your lemon tree if you are invested in having it thrive and produce healthy, bountiful, juicy, and flavorful fruit.

Fruit bearing trees consume much more energy than other types of plants, as growing fruit is a laborious and therefor high energy consuming activity. In order to produce fruit, plants need adequate amounts of sunlight, water, and nutrients. Plants intake these elements and through photosynthesis transform them into fuel to grow and produce.

While it is common knowledge that plants need water and sunlight for growth, nutrient uptake plays as big a role as water and sunlight do in fueling plant growth processes. By making sure your lemon tree has access to enough of all of the proper nutrients, you will help it thrive and produce an abundance of juicy lemons for you to enjoy.

During which season should I fertilize a lemon tree?

As a rule of thumb, you should always fertilize during active growth. For lemon trees (and most plants) this means spring and summer. Cease fertilization at the end of summer, or after your tree’s natural production begins to slow. Do not fertilize your lemon tree during the winter months.

How often should I fertilize a lemon tree?

Starting in early spring, fertilize your lemon tree as often as once every 4-6 weeks through summer. Fertilizing at periodic intervals of 4-6 weeks during active growth will ensure your lemon tree has access to enough nutrients to grow and produce fruit. When your lemon tree slows down production at the end of summer, stop fertilization until the following spring. Be sure to fertilize your lemon tree every year during the appropriate seasons.

If watering your lemon tree every 4-6 weeks during growing season sounds like a potentially problematic commitment, there are also slow release fertilizer methods available that reduce the frequency with which you need to fertilize. Usually a slow release fertilizer comes in the form of spikes which you insert into the soil of the lemon tree. If using a fertilizer with a slow release method, you will only need to fertilize your lemon tree once a year, in early spring.

What type of fertilizer should I use for a potted lemon tree?

If your tree shows no signs of deficiency or ailment, choose a general citrus fertilizer high in nitrogen, phosphorus, and potassium, and including a smorgasbord of micronutrients such as magnesium, calcium, and sulfur. This general citrus fertilizer is full of a balanced mix of all of the nutrients a lemon tree needs, and is a great option for giving your lemon tree a boost to encourage healthy growth and fruit production.

Another option is to choose a slow release fertilizer formulated for citrus trees. The main benefit of using a slow release fertilizer is that you would only need to fertilize your lemon tree once a year, as a singular application will slowly release nutrients to the plant over the course of the growing season. Because of this, slow release fertilizers can be a great option for those with a busy lifestyle or for those who want to “set it and forget it.” Usually slow release fertilizers come in the form of spikes which you insert into the soil of your plant. This one is specially formulated for citrus trees, has great reviews on Amazon, and is the perfect-sized spike for a potted lemon tree.

If your tree has yellowing leaves you suspect to be a result of a nutrient deficiency, consider testing the soil to figure out exactly which nutrients your lemon tree is lacking. At-home soil tests that are sent away to a lab can be incredibly helpful in giving insight into the nutrient breakdown of the soil. This soil test kit even sends you a report detailing the exact kind of fertilizer you should use to bring your lemon tree’s soil back to optimal nutrient composition.

It’s a good idea to test your lemon tree’s soil before applying a fertilizer not only to determine what type of fertilizer to purchase, but also because yellowing leaves can also be a symptom of other ailments. If your soil test comes back reporting ample levels of all important nutrients, look to other causes such as too much or too little water, or a pest infestation.

Applying the fertilizer

Different fertilizers have different concentrations and therefore different application guidelines when it comes to amount of fertilizer that needs to be applies. Follow the instructions included with the specific fertilizer you choose on how much fertilizer to apply to the soil of your lemon tree. Keep in mind that liquid fertilizers are usually concentrated and will need to be diluted with water. Also keep in mind that if your lemon tree is potted, it will need less fertilizer than an in-ground specimen, as the soil and its nutrient content are contained within the small confines of a pot.

Use the height of the lemon tree to determine how far from the trunk you should disperse the fertilizer. If the tree is 2 ft tall, apply the fertilizer in a 2 ft diameter surrounding the trunk of the tree. If the tree is 12 ft tall, apply the fertilizer in a 12 ft diameter surrounding the trunk of the tree. Using these guidelines will ensure all of the tree’s roots have access to nutrients and will promote even and healthy nutrient uptake.

If using a dry fertilizer, water the fertilizer into the soil after topical application.

If using slow-release spikes, insert the number of spikes recommended in the product instructions into the soil near the lemon tree.

Take care to not over-fertilize the plant as this can cause root burn. Similarly, avoid applying fertilizer directly to the trunk as this can also burn the trunk.

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