When I was visiting my parents recently, I was excited to see their lime tree had a plethora of fruit. So, it was sad to hear they hadn’t been able to enjoy them since the limes would fall off before ripening. It turned out this was from a lack of fertilizer. So, I did some research and helped them get their lime tree back on track. Here’s what I learned.
The best fertilizer for a mature lime tree is compost or a synthetic fertilizer with an NPK ratio of 2:1:2. If you’re fertilizing a young tree, use an NPK ratio of 1:1:1 instead (a 5-5-5 formula, for example). When using synthetic fertilizer, ensure it doesn’t directly touch the tree or its roots.
Have more questions about lime tree fertilizer? Continue reading for some examples and ideas, including how to make your own homemade lime tree fertilizer.
If you’re looking for a quick, but good fertilizer to use for your lime tree, I recommend Down to Earth’s Organic Citrus Mix on Amazon. If you want more options, you can find more brands of citrus fertilizer on Amazon here.
What to Look for in Lime Tree Fertilizers
There are two main ways to fertilize a lime tree. The first is with a small layer of compost and the second is by using a synthetic fertilizer specially formulated for citrus trees.
If you decide on a synthetic fertilizer, it can be tough to know where to start.
To help make shopping for lime tree fertilizer easier, stick to these key indicators:
- Opt for a high nitrogen formula
- Look for well-known brands like Down to Earth
- Buy organic when you can
- When in doubt, use a good compost
The ideal lime tree fertilizer for mature trees should include a high nitrogen and potassium percentage. Other nutrients important to fruit development include magnesium, copper, zinc, and boron.
When fertilizing young lime trees, you should still look for one with a high amount of nitrogen and potassium, but also one with more phosphorus. So, using a fertilizer with a 5-5-5 NPK (5% of each nitrogen, phosphorus, and potassium) or equivalent 1:1:1 ratio would work well for developing a young lime tree.
This balanced fertilizer will help the tree grow evenly and prepare it to have healthier blossoms. The trouble with using a synthetic fertilizer that’s only high in nitrogen is that the nitrogen would encourage foliage growth, but lack the other nutrients to develop blossoms, fruit, and roots. If the lime tree is mature and blooming, it will need a balanced mix of nutrients. For this reason, a ratio of 2:1:2 or 2:1:1 (like a 6-3-3) will work well.
When Do You Fertilize Lime Trees?
The best time to fertilize lime trees is in early spring or late summer. Winter is usually not a good idea to fertilize as citrus trees are more dormant and can’t readily use the nutrients. If the nutrients sit there long enough, they can burn the tree and its roots.
From spring to early fall, the lime tree is in its growing season and will require the most nutrients. Lime trees are heavy feeders already, so it’s a good idea to know how you’re going to fertilize it in advance.
How Do You Fertilize a Lime Tree?
Once you decide on if you’re using compost or synthetic fertilizer, you can figure out how much and where you should be applying the fertilizer. Here’s a quick guide for each.
- Apply 1-2 inches of compost on top of the soil
- Refrain from letting the compost touch the tree or the roots directly
- Apply once per growing season, or as needed
- Use a small (or the suggested) amount of fertilizer
- Apply away from the tree and its roots, but still under the foliage of the tree
- Bury the fertilizer 6-8 inches and try not to damage the roots
- Water well to dilute and spread the nutrients through the soil
- Apply 1-2 times per year, preferably in the spring and late summer
Remember to fertilize depending on the instructions on the package. Some fertilizers are stronger than others, so there’s not really a golden rule of how much to use.
If you’d like to play it safe, consider skipping the synthetic fertilizer and instead use 1-2 inches of compost twice a year for a complete profile of nutrients. Remember, compost for lime trees works best if the soil is already optimized (loamy and sandy). Lime trees, and other citrus trees, don’t well in alkaline or clay-based soil.
If you find your lime tree has yellow leaves, fruit falling off, or other issues, consider supplementing other nutrients in slowly (more on this later).
You can even use a homemade fertilizer that can provide a complete profile of nutrients for your growing lime tree. The best part is that you can adjust the nutrients yourself. So, if you find that your lime tree needs more phosphorus, you can simply add a bit of bone meal or leaves from your lawn. The same goes for other nutrients like nitrogen, potassium, sulfur, calcium, magnesium, iron, and more.
To see how you can create your own homemade blend of citrus fertilizer, visit my post below.
Can You Apply Too Much Fertilizer?
It can be easy to apply too much fertilizer. Unfortunately, by the time you find out, it’s likely too late as the lime tree starts to die. Make sure to buy a reputable brand of fertilizer and read the instructions, especially if you’re fertilizing a dwarf or potted plant.
If you decide on using synthetic fertilizer, and not compost, then you should also be aware of a few issues that can develop.
First, synthetic fertilizer is made to have a slow or fast-release, meaning a lot of the concentrated nutrients will spread in the soil either slowly or quickly. While lime trees are heavy feeders, they can still be overloaded if they get too many nutrients in a short time. If their soil gets too saturated with nutrients (especially nitrogen), their roots can get chemically burned. With this, the tree can die fairly quickly.
What to Do if the Lime Tree’s Leaves or Fruit Are Changing Color or Falling Off
If you’ve applied fertilizer recently, but notice your lime tree’s leaves or fruits are now discolored or falling off, then there’s a chance you either fertilized too much or were missing some key nutrients in your mix.
If this happens, first try giving the lime tree’s soil a good soaking and waiting a week. This will help disperse the nutrients if it’s too much, and weaken the concentration.
You should see an improvement, but in the off-chance you don’t, the likely issue isn’t over-fertilizing, but a deficiency. First, start by inspecting the package of the synthetic fertilizer and see what the primary nutrients are. Depending on the mix, you could use the process of elimination and find out which primary nutrients are lacking (feel free to reference my homemade fertilizer post linked above to see a full list of nutrients for citrus trees).
If you aren’t sure which nutrients to supplement, you can use either compost or Down to Earth’s 6-3-3 citrus fertilizer as a balanced source of nutrients. Here’s another link to Down to Earth’s Citrus Mix on Amazon if you’re interested.
Lastly, here’s a cool guide on leaf color and nutrient deficiencies that might help.
If you’d like more information about why lime leaves turn yellow and how to fix them, see my post below.
Are Coffee Grounds Good for Lime Trees?
Coffee grounds are good for lime trees due to their high acidity and nitrogen content. Like other citrus trees, lime trees prefer acidic soil ranging from 6.0-7.5 pH. For best results, dry the coffee grounds before applying to prevent mold buildup.
You can’t really use too many coffee grounds as they’ll easily disperse in the soil. However, if you have a potted or dwarf lime tree, then it’s possible to use too much. If this is the case, consider only applying a layer of coffee grounds every now and then. It’s not likely the soil will get too acidic, but if you believe it might be, then look into getting a soil pH test to determine if the pH is 6.0-7.5 (6.5 ideally).
Lime trees prefer a fertilizer with a high amount of nitrogen and potassium (if they’re still growing, then they’ll need phosphorus too). There are some issues that can happen when applying fertilizer, so read the directions and apply sparingly. Douse the soil with water to weaken the concentration of nutrients and to help prevent a chemical burn to the tree and its roots.
If you’re considering passing on the synthetic fertilizer, I don’t blame you. Instead, try using a 1-2 inch layer of compost twice a year. Remember, try to fertilize in spring or late summer. Don’t fertilize in the winter!