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Our 6 Picks for the Best Kumquat Fertilizer

Using soil, water, and sunlight to grow kumquats is simple. But those three necessities alone won’t guarantee healthy-growing kumquat trees.

Photosynthesis provides food for our trees, but they need fertilizer to take in nutrients that the soil may lack. The question is, with so many fertilizers, how do you choose the best?

Read on to learn about our picks for the best kumquat fertilizer!

Kumquats on a tree. Kumquat fertilizers keep your tree healthy and productive.

Best Overall

Down-to-Earth Organic Citrus Fertilizer Mix

Down to Earth Organic Citrus Fertilizer Mix 6-3-3, 5 lb

Down-to-Earth’s mix of slow-releasing nutrients is perfect for nourishing kumquat trees. However, they’re not the only ones that can do that!

The fertilizer comes in a box that works as an additional fertilizer, giving you more for your kumquats! Down-to-Earth packs its fertilizers in 100% recycled boxes so they can be shredded as compost!


  • Long-lasting
  • Proper rationing of nitrogen, phosphorus, and potassium
  • Comes in a box that works as compost


  • May attract gnats
  • Stinky odor

Best Fast-Acting

Calcium Nitrate Fertilizer

Hoss Calcium Nitrate Fertilizer

If you need a quick release of nitrogen, this water-soluble formula will give you a boost. Despite no potassium in the ratio, it improves the uptake of said nutrient!

Your kumquats can also benefit from the calcium since it increases fruit quality and prevents pests and diseases!


  • Works fast
  • High-nitrogen content
  • Four ways to apply it


  • Unbalanced N-P-K ratio

Best Organic

Epsoma Organic Citrus-Tone Citrus and Avocado Food

Espoma Organic Citrus-tone 5-2-6 Natural & Organic Fertilizer and Plant Food for all Citrus, Fruit, Nut & Avocado Trees; 4 lb. Bag. Promotes Vigorous Growth & Abundant Fruit

Do you prefer fertilizing kumquats with natural and organic ingredients? Epsoma Organic Citrus-Tone is for you!

Epsoma’s Bio-tone (beneficial microbes) aids in plant growth, producing a high yield of flavorful fruit. No burning, toxic, eco-unfriendly chemicals included!


  • Non-burning
  • Enhances the size and taste of fruit
  • Long-lasting


  • Stinky odor

Jack’s Classic Citrus FeEd

J R Peters Inc 52524 Jacks Classic No.1.5 20-10-20 Citrus Food Fertilizer

This granular citrus feed’s high-level N-P-K ratio serves heavy-feeding kumquats well! You’ll see a high yield of kumquats among strong branches and green leaves on their tree!

Jack’s Classic Citrus FeEd can also revive flailing citrus trees. If your kumquat trees have yellow leaves or there’s not enough fruit, adding this feed will fix them!


  • Enhanced nutrient levels
  • Nutrient uptake in not only roots but also leaves (when used correctly)
  • Perfect for restoring foliage and producing more fruit


  • Inorganic
  • Frequent application (every seven to 10 days)

EB Stone Organics Citrus and Fruit Tree Food

Citrus & Fruit Tree Food 7-3-3, 15lb.

Fertilizers give application directions on new and established fruit trees. But they don’t always list the rates according to age, till there was EB Stone Organics Citrus and Fruit Tree Food.

This fertilizer will give you specific application rates for each age of your kumquat tree. The rates increase when the tree ages, but bountiful kumquats are the reward!


  • Organic
  • Long-lasting
  • Listed directions for specific ages of citrus trees


  • Frequent application as the citrus trees mature

Dr. Earth Natural Wonder Fruit Tree Fertilizer

Dr. Earth 70656 1 lb 5-5-2 MINIS Natural Wonder Fruit Tree Fertilizer

The organic ingredients for Dr. Earth’s Fruit Tree Fertilizer are perfect for kumquats! Among those ingredients are bone meal and alfalfa meal, which help produce fruit and resist diseases.

The nutrients are released quickly, meaning the fertilizer dissolves fast in the soil, producing faster results. But just like slow-releasing fertilizer, this natural wonder feeds your kumquats for a few months!


  • Safe for people and pets
  • Organic and non-GMO certified
  • Feeds for about two to three months


  • Strong odor

Understanding the N-P-K Ratio

Before choosing the best fertilizer for kumquats, let’s review three hyphenated numbers on fertilizer labels. For example, if you see numbers like 8-3-7, that’s the N-P-K ratio.

Closeup of nitrogen, phosphorus, and potassium used in fertilizers.

N-P-K stands for nitrogen, phosphorus, and potassium—three nutrients for plant growth. The numbers represent the percentages of these nutrients. The example means 8% nitrogen, 3% phosphorus, and 7% potassium, in that order.

Other Types of Fertilizers for Kumquats

Commercial fertilizers can sometimes be pricey. Luckily, there are other ways you can fertilize kumquats!


Instead of pitching the following organic waste, save them for the soil under your kumquat tree!

  • Banana peel: Dig this into the soil around your tree and water it for a potassium boost.
  • Coffee grounds: Place these dry grounds around your tree to provide this citrus nitrogen, phosphorus, and a little acid.
Banana peels are an organic homemade fertilizer.


Mulch moistens the soil and prevents weeds from growing and stealing nutrients. Just place two inches of leaves, bark, grass clippings, or pine needles three to five inches around your tree!

Liquid Fertilizers

Spraying liquid fertilizer is perfect when your kumquat tree’s growing, especially if you need a nitrogen boost! You can either buy the following liquid fertilizers or make them yourself.

Remember to dilute the liquids if you make them!

When to Use Fertilizer for Kumquats

After planting your kumquat tree, wait until it starts growing. And in the spring, you can apply fertilizer.

Three times a year is the recommended schedule. But that depends on the fertilizer you use and its directions.

Things to Consider Before Fertilizing Kumquats


Check your soil’s pH level. A balanced level of six or seven means there is enough nutrients in the soil. So no fertilizing unless the level’s lower or higher.

You can test the soil’s pH level by using a test kit from a home and garden center.

A soil tester.


Water your kumquat trees before and after you use fertilizer. Watering dilutes the fertilizer to prevent burning the trees. That’s why you have to dilute your homemade liquid fertilizer.

Take care not to overwater, especially if the trees are old. Just enough to keep the soil moist is all you need.

Applying the Fertilizer

When applying, keep the fertilizer from touching the tree trunk or stem. Besides soil, you can apply it on the leaves, but first, check the type and label of your fertilizer.

And take care to follow the application rates given on a fertilizer’s label to avoid overfertilizing your kumquat trees.

Choose Your Best Fertilizer for Kumquats!

Closeup of kumquat fruit on a tree.

You now have an idea and plenty of options on what kumquat fertilizer is best for your citrus tree! Whichever you choose, follow the directions on the bottle or package, and your kumquats will be good to go!

And visit our kumquat trees page to learn more about how to care for these mini-oranges!