When I went to Thailand, I took a cooking class and will forever remember using fresh kaffir lime. I had no idea the lime (or even its leaves!) could add that much taste to a dish.
A few months later, I was lucky enough to stumble across a kaffir lime tree at my local nursery. 10 minutes later, I was in my backyard planting it.
If I knew then what I know now, I’m sure I could have helped it have a more prosperous year.
Simply put–fertilizer. And the proper amount of it.
Fertilizer helps provide trees with nutrients that are being depleted in the soil. And citrus trees, like kaffir lime, require a lot more nitrogen than most plants. It’s recommended to feed it 2 to 3 parts nitrogen for every part phosphorus and potassium. You’ll be able to see these ratios on the labels of store-bought fertilizer.
As for other minerals, iron, zinc, and manganese can also help the tree grow and fruit.
But being the wannabe homesteader that I am, you can bet that I prefer a homemade fertilizer and I listed that below too.
Which Fertilizers to Use for Kaffir Lime Trees
If you’re looking for an easy, store-bought fertilizer for your kaffir lime tree, there are some well known brands like Dr. Earth and Down to Earth that will work well. I’ve tried both of these brands and have had no problems, but I’ll link an alternative one below too.
1. Dr. Earth
Dr. Earth’s organic fruit tree fertilizer is made up of a 5-5-2 blend, 5% nitrogen, 5% phosphorus, and 2% potassium. While the extra nitrogen is what we’re looking for, the higher phosphorus content is great for root, flower, and fruit growth.
If you have dogs, don’t leave the bag around. Bury the fertilizer and hide the bag. They love the smell and will try to get into it!
2. Down to Earth
I first found Down to Earth from my local nursery, and this brand has plenty of options when it comes to fertilizer. The times that I’ve used it, it’s worked well and as a bonus, the packaging is compostable. So, feel free to toss it in your compost pile.
Their mix has a nutrient ratio of 6-3-3 (double the nitrogen to phosphorus and potassium, perfect ratios for what we’re looking for).
Now that you have an idea of some store-bought fertilizers, the only difference is, kaffir limes are dwarf trees (which are often grafted), so we’re going to apply less fertilizer than other citrus trees (more on this later).
But first, if you are looking for something more natural and homemade, then I have an idea for you.
3. Homemade Fertilizer for Kaffir Lime Trees
To make the best homemade fertilizer for your kaffir lime tree, all you need to do is save two food scraps from being tossed.
- Coffee grinds
If you currently throw these out, you may want to reconsider as they’re the perfect fertilizer to use for most plants on your homestead.
But citrus trees, in particular, benefit even more. That’s because they require higher nitrogen and more acidic soil.
Coffee grinds can meet both of these needs by naturally providing acidity and good nitrogen levels.
Eggshells are more of a bonus. They’ll provide your tree with a high amount of calcium. With the extra calcium, its flowers and fruit will be more abundant and hold better. Plus it will give the leaves a little extra shine.
So, you can save money by not buying fertilizer, and instead, use your old coffee grinds and eggshells to give your kaffir lime just about everything it needs. Remember that sterilized, not raw, eggshells work best (boiled egg fanatics, now’s your time to shine).
How to Fertilize Your Kaffir Lime Tree
The best times of year to fertilize your kaffir lime tree are during winter and spring. You can apply a fresh layer once or twice during each of these seasons.
As for how much fertilizer to use, that will depend on if your tree is planted or potted. Planted trees require more, while container trees need less.
If your tree is planted in the ground, some of the fertilizer will get spread throughout the soil and used by other plants (or just remain in the ground, unused).
Here are some things to keep in mind when fertilizing your kaffir lime tree:
- Use a slow-release, high-nitrogen fertilizer
- Apply it just under the first inch or two of soil
- Do not apply it closer than the drip line of the tree
- Water as needed to help the slow-release fertilizer
How Much Fertilizer to Use for Planted Kaffir Lime Trees
When fertilizing kaffir lime trees, the amount of fertilizer depends on the quality and ratio of nutrients. You can look at the bag’s instructions for more details.
But in general, a good rule is to use one pound for every year of the tree’s age. So a two-year-old tree will require two pounds for example.
You can continue doing this until you hit four pounds, at which point is the suggested annual volume for a mature kaffir lime tree. So the fifth year and each year after will require a maximum of four pounds annually.
If you have your kaffir lime tree in a container, you may want to skip the fertilizer altogether.
A potted tree only has a finite amount of soil to work with. Meaning, it can’t grow its roots to get other nutrients around it, like it can if it was in the ground.
So, by adding fertilizer, disturbing the balance in the soil is much more likely.
But if the leaves are yellowing, and you’re giving your tree enough sun and not over-watering it, then you may want to consider adding a small amount of slow-release fertilizer.
How Much Fertilizer to Use for Potted Kaffir Lime Trees
A safer measure for fertilizing potted kaffir lime tree is to add 1-2 inches of mulch every year. The mulch will slowly break down and provide nutrients for the soil.
If you’re still hesitant on store-bought fertilizer, adding dried coffee grounds as a mulch every 1 to 2 months would also be a good natural solution here.
Can You Over-Fertilize Kaffir Lime Trees?
Yes! You can easily over-fertilize your kaffir lime tree. Adding a large amount of quick-release nitrogen can burn the tree. If left in this state, the tree will most likely die.
This is why it’s important to keep in mind to use the few points we touched on before. Once again, use a slow-release fertilizer, don’t apply it past the drip line of the tree, and water regularly to dilute it.
Finding the best fertilizer for your kaffir lime tree all depends on if it is planted or potted. From there, you can decide if you want to use store-bought or homemade fertilizer. My favorite and most effective homemade options on my homestead are coffee grinds and eggshells.
Fertilizing once or twice during winter and spring are good measures. Lastly, make sure not to over-fertilize and you will enjoy the limetastic leaves and fruit these dwarf trees are known for.