5 Best Plum Tree Fertilizers | How and When To Use

Like many other fruit-bearing trees, plums have been a part of human history for millennia. It’s believed that plum trees were first cultivated in China over 2,000 years ago. From there, the fruit made its way across Asia to Rome and, eventually, throughout the rest of the world.

Today, plum trees can be found growing in orchards as well as in the wild. As members of the rose family, plum trees are equally as cherished for their fragrant flowers as they are for their fruit. 

A plum tree is a perfect addition to any ornamental landscape or food garden! While plum trees are fairly low maintenance, they still require routine care to reach their full potential.

Since I know just how daunting it can be to select the right fertilizer for fruit-bearing trees, I’ve put together a detailed guide on what to look for. I’ve also highlighted some of my favorite plum tree fertilizers so you can jump straight to the good stuff.

Best Plum Tree Fertilizers

If you’re in a rush, here are my top recommendations for plum tree nutrition, but for details of why, when, and how to feed these culinary fruiting delights, be sure to read through to the end.

Jobe’s Fruit & Citrus Fertilizer Spike 4-6-6

Best for Potted Plum Trees

Jobe’s Fruit & Citrus Fertilizer Spike 4-6-6

Pre-measured fertilizer spike is designed to be pushed an inch into the ground to provide a slow-release feed right through the growing season.

Best Plum Tree Fertilizer

Best Organic

Down to Earth Organic Citrus Fertilizer Mix 6-3-3

Organic slow-release fertilizer containing 100% natural ingredients plus micronutrients. Down to Earth’s 6-3-3 formula is great for plum trees as well as citrus fruit and avocados. 

Jobe’s Organics Fruit & Nut Granular Fertilizer 3-5-5

Best Slow-Release Granules for Plum Trees

Jobe’s Organics Fruit & Nut Granular Fertilizer 3-5-5

Slow-release granules, ideal for ground-planted, mature plum trees. Contains Jobes’ patented bio-zome to help improve the condition of the soil.

By the way, our site is supported by visitors like you. Some links on this page may be affiliate links which means if you choose to make a purchase, I may earn a small commission at no extra cost to you. Thanks for your support! You can find out more here.

Choosing the Best Fertilizer for Plum Trees

Plum trees perform best when fertilized with a relatively balanced fertilizer. Keep in mind that micronutrients like boron, manganese, zinc, and iron are just as important as your fertilizer’s N-P-K ratio.

Along with ensuring your plum tree’s fertilizer contains adequate macro and micronutrients, pay close attention to the soil’s pH level. Plum trees growing in overly alkaline soil often have trouble absorbing micronutrients.

When it comes to plums and other fruit trees, many gardeners feel more comfortable using organic fertilizers. While I personally feel that synthetic fertilizers are equally as safe when used correctly, the decision is entirely up to you.

Plum Tree Fertilizer N-P-K Ratio

Fertilizer manufacturers advertise the percentage of nitrogen, phosphorus, and potassium in their products using a simple system called an N-P-K ratio. This ratio is a sequence of three numbers (divided by hyphens) that’s often displayed prominently on the fertilizer packaging.

A fertilizer labeled 10-8-12 contains 10% nitrogen, 8% phosphorus, and 12% potassium. Once you understand this formula, it’s easy to decide which fertilizers are right for your plants.

Since plum trees consume a lot of nitrogen — this is especially true during peak fruit production — you’ll want to pay close attention to the first number of any N-P-K ratio. The importance of the other two, phosphorus and potassium, will depend on your native soil composition. 

Boron, manganese, zinc, and iron

Boron deficiencies typically show up in the fruit themselves rather than in the foliage, branches, or roots of plum trees. You’ll likely notice bruising or soft, sunken spots on mature fruit. Since little can be done at this point, it’s important to monitor your soil’s boron levels early in the season.

Too little manganese can affect your plum tree’s leaves, flowers, and fruit. Watch for tell-tale signs like smaller leaves, flowers, and fruit or dramatic fruit drop.

Zinc and iron deficiencies are often caused by soil that is too alkaline (or a pH that is too high). Common signs of deficiencies include poor leaf development and chlorosis (yellow foliage with green veins).

Plum Soil pH and Nutrient Uptake

Plum trees thrive in slightly acidic soil with a pH between 6.0 and 6.5. Since this is the typical range of native soil, adjustments are rarely needed.

Soil pH is important because it impacts how readily roots can absorb certain nutrients. A pH that is too low or too high will make some nutrients almost impossible to absorb.

Granular Vs Liquid Fertilizer

There are several ways to deliver nitrogen, phosphorus, potassium, and key micronutrients to your plum tree. The two most popular options are granular or liquid fertilizer. 

Choosing one formula over the other part comes down to personal preference. But I also find that there are clear benefits (and drawbacks) to using granules vs liquid.

Liquid Concentrate or Spray

I recommend reaching for a liquid fertilizer when feeding young or freshly transplanted plum trees. It’s much harder to overfertilize with liquid vs a granular formula, and liquid fertilizers tend to have lower salt contents. 

However, liquid fertilizers aren’t my personal go-to when feeding large, established fruit trees. The biggest issue with these formulas is that they are expensive. And liquid fertilizers don’t provide a steady, gradual stream of nutrition the way granules do.

Fertilizer Granules

While granular fertilizers can burn the roots of young or compromised plants, they’re ideal for feeding established fruit trees. A slow-release granular formula can feed a mature plum tree for several months at a time.

Fertilizer granules are almost always the most affordable option. Even if you opt for a liquid formula for your first feeding of the season, switching to granules for the rest of the season will certainly save money.

Fertilizer Spikes

Fertilizer spikes are rarely my top choice when feeding plants of any considerable size. I’d recommend using fertilizer spikes only for small (or potted) plum trees. 

Organic vs Synthetic Fertilizers

Organic fertilizers are those made from biological waste (e.g., decaying plant matter or animal manure) and other organic sources. 

Synthetic fertilizers are manufactured from inorganic resources. Their intense concentration of chemicals often means that plants and trees respond quicker when compared to using organic products.

Best Plum Tree Fertilizer Reviews

After reviewing some of the leading plum tree fertilizers available, I’ve put together a list of my favorites for a variety of nutritional needs and growing circumstances. You’re sure to find the perfect fit for your own plum tree below.

Pros

  • Easy to use with no measuring required
  • Supplemented with Jobe’s Biozome soil-supporting microbes
  • Ideal for smaller or potted plum trees

Cons

  • Expensive if used for larger plum trees

If you’re looking for the most convenient fertilizer for small or potted plum trees, I recommend these pre-measured spikes from Jobe’s.

This formula contains a relatively balanced N-P-K ratio with lower nitrogen for decreased risk of fertilizer burn. It’s been specially formulated for plum and other fruit-bearing tree varieties, and you can be sure your plum trees are being taken good care of thanks to Jobe’s organic formula.

Essential nutrients aside, these fertilizer spikes also contain beneficial microbes for improved soil health. So, if it is strong roots, healthy growth plus pest, disease, and temperature stress avoidance you are looking for in your potted plums, then these are the spikes you need.

How To Use: Using the included plastic cap, drive fertilizer spikes into the soil using a mallet. Follow the package directions to determine how many spikes to use for your particular plum tree.

Pros

  • Made with OMRI-approved organic ingredients
  • Packed with important micronutrients

Cons

  • Several boxes needed to fertilize large trees

Since so many home gardeners would rather use organic fertilizer on their fruit and vegetables, it would be a shame not to highlight this granular formula from Down to Earth.

Don’t let the citrus label fool you. This fertilizer is also a great option for plum trees as well as their nutritional needs.

All Down to Earth fertilizers have the OMRI seal of approval and contains 100% natural ingredients. This one boasts several key micronutrients to support healthy growth and fruit development. In addition, routinely applying this fertilizer may prevent common nutritional deficiencies in plum trees.

How To Use: Apply 1 cup of fertilizer per inch of trunk diameter throughout the drip line of plum trees. Gently work into the soil and water thoroughly.

Pros

  • Certified organic by the USDA
  • Feeds fruit trees while improving native soil health
Cons
  • The odor may attract garden pests

I really like Jobe’s Organics fertilizer and when it comes to feeding larger, more mature trees, this granular fruit and nut formula is a cost-effective option.

Of course, this fertilizer contains Jobe’s Biozome blend of beneficial soil microbes, which simply means that consistent use of this product could improve the health and quality of the soil around your plum trees.

How To Use: For smaller trees, apply 3 cups of fertilizer per inch of trunk diameter to the drip line of plum trees. Trees over 3 inches in diameter should be fed at a rate of 9 cups per inch.

Pros

  • More affordable than other plum tree fertilizers
  • Slow-release nitrogen provides nutrition for 6 weeks at a time

Cons

  • Not appropriate for high-potassium soil

There’s nothing wrong with turning to a trusted brand name like Miracle-Gro to feed your plum trees. This fertilizer contains slow-release nitrogen to support plum and other fruit production without the risk of overfeeding. 

Extra doses of iron, magnesium, and manganese make this granular formula ideal for soil low in micronutrients or for plum trees showing signs of manganese deficiencies such as smaller than usual leaves, flowers, and fruit, or dramatic fruit drop.

One bag of this Miracle-Gro product will go a long way, even when feeding established plum trees. It’s by far one of the most economical options I’d recommend to home gardeners.

How To Use: Evenly distribute fertilizer granules around the trunk of your plum tree — be sure to spread fertilizer throughout and slightly beyond the drip line. Rake granules into the top inch of soil before watering thoroughly.

Pros

  • The nutrient-dense formula is appropriate for established trees
  • Feeds plum trees for 6 months at a time

Cons

  • Large plum trees will require several spikes

My final selection from Miracle-Gro offers pre-measured fertilizer spikes designed for the needs of fruit-bearing trees including plums as well as lemons and oranges (to name but a few). 

These large spikes can feed trees for 6 months at a time so they are the perfect option if you want to fertilize right at the beginning of the season and then forget about it.

Compared to other fertilizer spikes, this formula boasts a fairly high N-P-K ratio and so to prevent over-feeding or fertilizer burn risk, I recommend using these for more mature plum trees or those that are at least a couple of years old.

How To Use: Locate the perimeter of your plum tree’s drip line. Drive spikes into the soil at least 3 feet from each other around this perimeter. Apply fresh spikes twice per year.

How to Fertilize Plum Trees

The general advice is to apply fertilizer throughout a tree’s drip line — the drip line is the section of soil directly below a tree’s canopy. But most trees grow roots well beyond this imaginary line. 

For the best results, I recommend fertilizing several feet beyond your plum tree’s drip line to cover about 1.5 times the canopy area. When feeding potted trees, apply fertilizer throughout the entire container. 

Avoiding Plum Tree Fertilizer Burn

Preventing fertilizer burn in the first place is the best treatment. Here are some precautions you can take to minimize the risk of fertilizer burn:

  • Avoid quick-release formulas
  • Perform a soil test before fertilizing
  • Be cognizant of fertilized lawns and/or garden beds nearby
  • Spread the fertilizer evenly throughout the drip line
  • Use foliar fertilizers sparingly
  • Do not fertilize when the tree isn’t actively consuming nutrients

When to Fertilize Plum Trees

Fertilize mature, fruit-bearing plum trees twice per year. Generally, these feedings occur in spring and mid-summer.

Young trees should be fed once per year. While some people prefer to fertilize in the spring, waiting until early fall gives the tree’s roots time to establish.

The secret to feeding fruit trees is to deliver nutrients well before they actually start producing fruit. For plum trees, this means that nitrogen-rich fertilizer should be applied at least a month before blooms appear. Later nitrogen applications encourage vegetative growth rather than flower or fruit production.

Fertilizing Plum Trees in Winter

You should never fertilize fruit trees when they are in winter dormancy. This can cause fertilizer burn or kick the tree out of dormancy much too early. At best, you’ll waste time and money applying fertilizer the tree can’t yet put to use.

What this advice is actually suggesting is that you should fertilize plum trees as soon as they exit dormancy. In many climates, this means fertilizing when it is technically still winter. A good rule of thumb is to hold off on feeding until you notice leaf buds forming on your plum trees. 

How Often to Fertilize Plum Trees

When using slow-release fertilizer, most plum trees do just fine with two heavy feedings per growing season. Particularly young and old trees perform best with just one annual application.

You should monitor your plum tree’s annual growth to determine its fertilizer needs. For most plum varieties, 12 to 18 inches of vertical growth is ideal. If your plum tree produces less than 12 inches of growth in a year, it’s likely in need of additional nutrition. But if it grows more than 18 inches, it’s likely to be overfed.

Verdict: Best Fertilizers for Plum Tree

Fertilizer is just one (very important) facet of plum tree maintenance. It can be hard to find time to do the necessary research when your garden’s to-do list seems to be never-ending! 

If you have a young plum tree growing in a small garden bed or container, you can try out Jobe’s Fruit & Citrus Fertilizer Spike 4-6-6. These pre-measured spikes take the mess and guesswork out of fertilizing potted trees.

Jobe’s Fruit & Citrus Fertilizer Spike 4-6-6

Best for Potted Plum Trees

Jobe’s Fruit & Citrus Fertilizer Spike 4-6-6

Pre-measured fertilizer spike is designed to be pushed an inch into the ground to provide a slow-release feed right through the growing season.

Even if you’re not sold on using organic fertilizer for plums, my personal favorite formula is Down to Earth Organic Citrus Fertilizer Mix 6-3-3. It may not be labeled for use on plum trees but contains everything your fruit trees could possibly need!

Down to Earth Organic Citrus Fertilizer Mix 6 3 3

Best Organic

Down to Earth Organic Citrus Fertilizer Mix 6-3-3

Organic slow-release fertilizer containing 100% natural ingredients plus micronutrients. Down to Earth’s 6-3-3 formula is great for plum trees as well as citrus fruit and avocados. 

To support soil health around large trees, I recommend Jobe’s Organics Fruit & Nut Granular Fertilizer 3-5-5. It contains all of the beneficial amendments found in the Jobe’s Organics spikes but in a standard granular formula.

Jobe’s Organics Fruit & Nut Granular Fertilizer 3-5-5

Best Slow-Release Granules

Jobe’s Organics Fruit & Nut Granular Fertilizer 3-5-5

Slow-release granules, are ideal to use for ground-planted, mature plum trees as well as other fruiting tree varieties such as mango and avocados. Contains Jobes’ patented bio-zome to help improve the condition of the soil.

FAQ’s Fertilizing Plum Trees