When to Use 10-10-10 Fertilizer? | How to Use Triple 10

For all of the available NPK ratio options on the market for your plants today, there is one that offers balanced nutrition with far less risk of root burn and overfeeding. This is the ever-popular 10-10-10 fertilizer. 

A fertilizing product that contains 10% of nitrogen, 10% of phosphorus, and 10% of potassium is what is commonly referred to as a balanced fertilizer. And depending on soil conditions, plant variety, and growth stage, this particular NPK has a plethora of fertilizer uses, from lawns and edibles to evergreen trees and shrubs, as well as flowering plants.

When to apply a 10-10-10 NPK, and in what quantities are all relative to the plant you are growing. All of which, I’ll be discussing more in detail, in this article.

Understanding 10-10-10 Fertilizer Labels

The prospect of deciding if a triple 10 fertilizer is what your plants need can be a challenge and may seem like a puzzle. When all you want to do is to grow healthy plants without breaking the bank.

Well, there is hope on the horizon! You can easily match an effective fertilizer to your specific plant goals. It’s simply a matter of getting to grips with the terminology used by manufacturers to explain the contents of their products. 

Each fertilizer label contains a list of ingredients plus the NPK ratio for that particular product. The NPK ratio denotes how much nitrogen, phosphorus, and potassium the product contains as a percentage.

The list, first of all, covers details of the NPK content and these are what we commonly refer to as macronutrients.

Next, will follow the details of the secondary ingredients (or micronutrients) and include minerals such as iron, magnesium, and calcium. This is closely followed by details of all trace elements included in the product such as copper, zinc, and manganese.

Lastly, the list will cover any fillers included by the manufacturer that are often included to make the product easier to use.

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N-P-K Ratio

So, how exactly do you decipher an NPK ratio? If you’re not familiar, an NPK ratio is three numbers, separated by dashes. This indicates the fertilizer’s proportions of nitrogen, phosphorus, and potassium.

As mentioned, a 10-10-10 NPK has 10% nitrogen, 10% phosphorus and 10% potassium. Every plant requires these three elements in order to thrive. Just in different proportions or NPK ratios.

Each of these macronutrients plays a vital role in cell formation, photosynthesis, and flower production. All working in tandem to create a healthy, bountiful plant. And when applied properly, they can increase soil fertility and beneficial bacteria activity, too. Read Plant Food Vs Fertilizer to understand the differences between the roles of plant nutrients and photosynthesis in plant growth.


Nitrogen plays a key role in encouraging the growth of healthy, green foliage, by fueling the production of chlorophyll. This gives foliage its green color and ensures that photosynthesized energy is available to convert starches and carbohydrates into food. 

This multi-faceted macronutrient is responsible for fueling the proteins and enzymes that regulate water and nutrient uptake and disbursement. High nitrogen fertilizer is typically formulated for lawns and other plants where foliage is the primary focus.


When it comes to the process of photosynthesis, Phosphorus plays a major role. After chlorophyll has been produced, phosphorous ensures that the energy stored by the chlorophyll can be converted into food from starches and carbohydrates. Use High phosphorus fertilizers when you are looking to increase flower and fruit production and size. 

From the point at which cells are created, Phosphorus helps to construct the proteins and enzymes that are later utilized by nitrogen to distribute water and nutrients throughout plant tissue.


This final macronutrient is primarily responsible for the circulation of water, nutrients, and photosynthesized food throughout your plants. Yet, it also activates those proteins and enzymes that were formed using phosphorus and nitrogen to build healthy plant structures. 

When potassium is absorbed at the right levels, it helps plants to conserve water. This in turn enables plants to be more effective in resisting diseases and coping with extreme heat and drought.

High potassium feeds are the perfect fertilizers for tomatoes or other vining crops such as squash and melons as they help to encourage large, well-formed fruit. 

Uses For Triple 10

The main reason for using a triple 10 fertilizer is to increase nutrient density in soil, which, when absorbed by plants, encourages growth and the healthy development of foliage, flowers, fruits, and roots.

Using a triple 10 fertilizer for hanging basket plants can help to overcome the heavy water and nutrient leaching that happens from regular watering. Allowing your plant consistent access to nutrients, as they grow.  

When applied in early Spring to ornamentals and vegetables grown in fertile soil, a 10-10-10 NPK helps to ensure the process of photosynthesis, leading to successful foliage and root growth and maximizing the potential for bud set. It’s worth noting that additional phosphorus and potassium are required after bud set, to ensure plentiful flowers and fruits.

For in-ground annuals and perennials, a 10-10-10 NPK will provide consistent nutrients, just as in hanging baskets and pots. Fewer applications will be needed here though, due to increased moisture and nutrient retention.

If used correctly, a 10-10-10 fertilizer is even recommended for use to feed houseplants.

Why Use a Balanced Fertilizer?

When planted in poor soil, a balanced fertilizer provides much-needed nutrients, that can then be absorbed by plants in order to encourage and promote healthy growth. 

Many plants and most indoor plants perform best with a balanced fertilizer largely because they require regular watering, plus nutrients are easily washed out of the soil through drainage holes. An equal NPK keeps the growing medium fertile enough to keep them happy.

How Often to Use

Liquid options can be applied to vegetables and ornamentals once a month to maintain a steady stream of nutrients. In well-composted soil, every other month is sufficient. 

Turfgrasses can use a triple 10 fertilizer 3 times per year, beginning in the spring. You can expect to see results from just one application within a week.

With slow-release options, like granules or spikes, even fewer applications are necessary. With beneficial soil microbes and periods of rainfall doing the work for you, while also enriching your soil. 

Results with these take a bit longer to see but the increased benefits are well worth the wait.

10-10-10 vs 8-8-8 Fertilizer

In terms of fertilizing, plants are typically categorized as heavy, medium, or light feeders. From this perspective, there isn’t much difference between a triple 10 and a triple 8 fertilizer (10% of each macronutrient vs 8%).

But, when using it to cover large plots, it’s important to note how much more of an 8-8-8 NPK is needed to reach optimum nutrient availability, than a 10-10-10. 

For example, 12.5 lbs of a triple 8 fertilizer would be needed (per 1000 sq ft) in order for the full NPK to be available to every plant. Only 10 lbs are needed with a triple 10. When cost is a factor, a triple 10 is often more economical.

Fertilizer Type

There are several application types available that make the process of nourishing your plants and soil less strenuous and more enjoyable. These fall into four different categories: 

  • Quick Release – these liquid or water-soluble options offer an immediate uptake of nutrients. Resulting in faster growth, and improvements that can be seen quickly, even when plants are grown in nutrient-depleted soil.
  • Slow-Release – granules and spikes a gradual release of nutrients in soil over a prolonged period. This prevents plants from being inundated with excessive amounts of nutrients in one hit. 
  • Organic – made from the bi-products of animals and composted plant matter, all of which are carefully selected for their naturally occurring macro and micronutrient content.
  • Inorganic – mass-produced using minerals and manufactured chemicals. Most users agree that results are usually better than their organic counterparts, however, they carry risks to people, pets, and our environment.

Liquid Concentrate

Liquid concentrates are used by mixing in a recommended amount of water and applying it around the base of plants. Some are also formulated to be used as foliar sprays and are quite effective when leaves show signs of nutrient deficiency. 

Ready-to-use formulas make for a very simple and effective way to fertilize but are often more expensive than concentrated versions. Once applied, nutrients are immediately carried to the root system through the soil or leaves.

Liquid feeds tend to keep the pH levels in your soil balanced, as well. However, caution is recommended, as over-feeding is common and could lead to root burn.

Water Soluble Powder

Water-soluble, powder fertilizers can be applied either directly into the soil around the base of trees, shrubs, and plants or diluted in water as a “tea”. This type is perfect for larger applications such as expansive allotments or home vegetable gardens.

As a dissolvable, the effectiveness per application is fairly consistent. As nutrients are equally dispersed throughout the solution when mixed with water. 

Powders are some of the most economical and carry the benefit of virtually indefinite shelf life. But, they do carry a risk of root burn, if exact measurements are not followed.

Slow-Release Granules

Granules are a slow-release choice. Heavily concentrated, these can provide a steady stream of nutrients directly into the soil for between four to nine months (depending on the brand you buy). Results are usually evident within just a few weeks.

They’re also less likely to damage roots through scorching and are considered better for the environment because there is little chance of leaching or run-off. This is because no watering is needed to activate, and the product is less likely to leach into nearby surfaces or groundwater. 

When applying granular fertilizers, simply cast by hand or use a spreader and direct them toward the base of your trees, shrubs, and plants. They can safely feed crops longer into the growing season and support even growth on lawns, while reducing the amount of fertilizer required, per season.

Fertilizer Spikes

Spikes are a doddle to use and are a convenient way to fertilize container-based plants or houseplants. They come in pre-measured quantities of varying sizes and work best when inserted into soils that are not heavy, dense, or compacted.

In compacted soil under large trees, simply water the area to be fertilized first. Then, gently tap spikes into softened soil with a rubber mallet.

A combination of moisture and soil-based microorganisms is needed in order to break down the nutrients that are held within the spikes.

And being slow-releasing, they run little risk of root burn. Unused portions can then be stored mess-free until needed.

How and When to Use Triple 10

All triple 10 fertilizers need to be applied to the soil before they can be absorbed by plants. Liquids are watered into the soil and granules are worked into the soil and then watered in.

I use 10-10-10 slow-release fertilizer if I’m planting young trees in nutrient-deficient soil. Adding a handful of granules to the planting hole ensures roots become established more quickly and also encourages new growth.  

When back-filling new borders and beds, I like to work slow-release granules into the top layer of soil before I begin planting.

A triple 10 fertilizer can also be used as a vegetable fertilizer right at the start of the growing season.

Avoid continued growth through the season, however, unless your soil is nutrient-poor. Most vegetables will need varying degrees of macronutrients. Leafy greens for example need more nitrogen and less phosphorous and vining crops such as squash and zucchini require phosphorous to help with flower and fruit production.

For flowering and fruiting veggies, follow this up with an NPK higher in phosphorus and potassium, once buds set. 

When used as directed, a 10-10-10 NPK is far less likely to cause the kind of burning that can result from high doses of nitrogen. But, despite the low ratio, care must still be taken not to over-apply it.

Trees and Shrubs

When used as a fertilizer for evergreen trees and shrubs, a triple 10 fertilizer can help to establish strong root systems and produce healthy color and size faster when for a month or two after planting. 

Increased soil fertility will also help these large plants develop an effective resistance against extreme temperatures. And to conserve moisture in times of drought.

Once established, perennial evergreens typically don’t require any further fertilizing. But, if browning or loss of foliage occurs out of season, a good soil test should be conducted to reveal what nutrient is lacking and needs to be added to the soil.

Citrus and Fruit Trees

If you’re planting young citrus and fruit trees in the Springtime and you know that the soil conditions are poor, then it is worth adding a few handfuls of dry 10-10-10 granules into the planting hole. This will help the root system get established more quickly and encourage plenty of leafy green foliage.

However, for a bountiful harvest, come summer and fall, you will need to amend the macronutrient levels after bud set to ensure your trees get the right amount of phosphorous and potassium to ensure successful fruit production and protect against diseases.


Ornamentals, in beds, pots, and hanging baskets, need consistent access to nutrients in order to produce lots of vivid, summer color. A triple 10 NPK can ensure this and help accelerate plant maturity in annuals. Resulting in buds and flowers appearing sooner.

Unless, they’re already growing in rich, fertile soil. In this case, a watered-down dose of 10-10-10 will better support a nice show of healthy stems, leaves, and blooms, without running the risk of overfeeding.  A full 10-10-10 NPK in rich soil may force extra growth and blooms but at the expense of the overall health of the plant.

Vegetable Gardens

Green, leafy crops like broccoli, cabbage, and lettuce grow best when side-dressed with a triple 10 NPK, roughly a month after planting. As do kale, celery, and asparagus. Showing strong root development and vigorous growth.

If your soil is poor, to begin with, it’s worth considering a 20-20-20 NPK right at the start of the growing season. But, once buds are set, less nitrogen is needed. Otherwise, you’ll have a lot of foliage and few flowers and fruit.

Is 10-10-10 Good for Tomatoes

When first planted in nitrogen-poor soil, a 10-10-10 NPK will provide new seedlings with the boost they might need to establish root growth and healthy foliage. But, beyond the first month of growth, I recommend a 5-10-10 fertilizer to encourage fruit production, protect against drought and keep diseases at bay.

Continuing with a triple 10 will produce lots of pretty green leaves, but with few flowers or fruit. The same applies to all varieties of squash and melons. 


Houseplants also need the right ratio of nutrients to form strong roots and healthy foliage and the nutrients in their soil are easily leached out thanks to their regular and frequent watering needs.

I find that a triple 10 liquid feed is a great option for houseplants and is gentle enough to minimize the risk of damaging roots and foliage. 

An exception would be when using fertilizer for African violets, bromeliads, and other flowering houseplants. These do well with a 7-9-5 NPK that offers additional phosphorus to support flower development and extra nitrogen for healthy foliage growth.

When adding extra nutrients to houseplants, please do so with caution.

Just as with outdoor plants, too much can overwhelm and kill your plant.

Lawn and Grass

Most liquid fertilizers for lawns and grasses include higher doses of phosphorus to produce a thick, lush blanket of color and form robust root systems. They also rely on higher levels of nitrogen to maintain a vibrant structure that’s also resistant to wear-and-tear, excessive heat, and drought.

When starting a new lawn fertilizing regimen, using a 10-10-10 NPK is a great place to start. If you haven’t tested the soil beneath, this will provide adequate nourishment without risking root and blade burn. 

Excessive amounts of any macronutrient on lawns and different grass types may end up causing root damage ultimately killing them.

10-10-10 Fertilizer FAQ’s