When Is 6-6-6 Fertilizer Best? | How to Use Triple 6

Using the right fertilizer is key to seeing lush, healthy growth in your plants. With so many types of fertilizers to choose from, though, it can be a challenge to find the best option for your garden setup. Here, I will discuss when and how to use 6 6 6 fertilizer to keep your greenery looking its best.

Understanding 6-6-6 Fertilizer Label?

All fertilizers have a clearly marked label that will tell you the ratio of primary nutrients in the bag, including nitrogen, phosphate, and potassium. 

Look out for three numbers, usually separated by a dot or a dash. This denotes the percentage of each nutrient in a package. The first number is the amount of nitrogen, while the second is the amount of phosphate. The third number represents the amount of potash, which provides potassium. 

Fertilizer boasting a 6-6-6 on the label contains 6% nitrogen, 6% phosphorus, and 6% potassium. For instance, a 50-pound bag of 6-6-6 would contain 3 pounds each of nitrogen, phosphate, and potash. The remainder of the bag is filler such as cottonseed or bone meal.

N-P-K Ratio

The ratio of nitrogen, phosphate, and potassium present in fertilizer can significantly impact how a plant grows and cycles. Each nutrient encourages different types of growth in healthy plants, so it’s important that you choose a fertilizer with the right ratio.


Nitrogen plays a vital role in plant growth and development. Without enough nitrogen, plants will appear stunted, withered, and yellow. By adding fertilizer with nitrogen to your soil, you can promote lush, leafy growth in plants ranging from lawn grasses to ornamental trees.


While nitrogen promotes growth above the ground, phosphorus is responsible for developing a healthy root system. It also plays a critical role in fruit and flower production. Fertilizers containing phosphate provide the phosphorus that plants need to reproduce and produce a healthy yield.  


Plenty of potassium makes for hardy plants that are resistant to heat, cold, and disease, as well as common pests. Potassium strengthens a plant’s immune system and supports overall health, especially during periods of stress. Fertilizer that includes potash can improve a plant’s growth, yield, and longevity. 

Fertilizer Type

There are several different varieties of 6-6-6 fertilizers. The type you use will depend on what type of plants you’re dealing with and how you plan to feed them.

Liquid Concentrate

Some fertilizers come in a concentrated liquid form that requires dilution with water before application. You can then apply fertilizer to plants evenly using a hose, sprayer or watering can.

Liquid concentrate fertilizers are fast-acting, so they are perfect to use when you need to quickly perk up a plant that looks like it needs a nutrient boost. Using liquid fertilizers on their own requires frequent applications for best results. This type of fertilizer is suitable for both indoor houseplants, garden borders, fruit, vegetables, and trees. 

Water Soluble Powder

Soluble powder fertilizers require water to become activated. Instead of diluting in water as you would do with liquid concentrates, you sprinkle the powder over the soil and then water your plants. 

Powder fertilizers offer a medium-release of nutrients and so the effects last longer than a liquid fertilizer but act faster than slow-release granules. Water-soluble powders are suitable for indoor and outdoor use and are usually applied as a top dressing and turned over into the top layer of soil.

Slow-Release Granules

Slow-release fertilizer works similarly to water-soluble powders, where nutrients are released into the soil gradually. But the solid form of the granules means they break down slowly there therefore their distribution of nutrients is prolonged, as particles dissolve from the granule.

After you mix dry granules into the topsoil and cover them, they disperse over time to maintain steady nitrogen, phosphorus, and potassium levels in the surrounding soil. Slow-release granules work well on lawns, flower borders, and indoor plants.

Fertilizer Spikes

Fertilizer spikes are a convenient slow-release fertilizer offering a “set it and forget it” method of plant care. You can drive a spike into the soil around your plant, and it will begin to disperse from the bottom up to release nutrients. A fertilizer spike can continue to release nutrients into the soil for up to three months at a time.

Spikes are an ideal delivery method for both potted and garden plants. They work well to deliver targeted nutrients to a single area. Keep in mind, though, that high concentrations of nutrients may leach from the spike. It’s important to leave plenty of room between spikes to prevent nutrient burn

What Is Triple 6 Fertilizer Used For?

Triple six fertilizers are a common all-purpose fertilizer used by gardeners to restore balance to their garden or potting soil and correct nutrient deficiencies. Rather than encouraging rapid growth, triple six helps to maintain a healthy balance of nutrients.

Where plants already benefit from nutrient-rich soil or are light to moderate feeders, one or two applications of 6-6-6 per year is enough to keep plants healthy and strong. 

Even with modest amounts of fertilizer, however, it’s a good idea to flush plants with plenty of water to avoid a build-up of product – usually salt – that can cause dehydration in plants. 

Unlike high-concentration fertilizers, 6-6-6 varieties and lower tend to be gentle on plants. Species that are sensitive to nutrient overload may do better with a triple six fertilizer as opposed to a 7-7-7 or higher balanced fertilizer.

Why Use a Balanced Fertilizer?

A balanced fertilizer such as any 6-6-6 variety works to keep plants healthy without encouraging excessive growth or fruiting. Many people use balanced fertilizers to maintain their yard or houseplants, replenishing nutrients lost or leaches from the soil throughout the course of the year. 

You can find a variety of strengths when it comes to balanced fertilizers. For typical soil upkeep, most gardeners choose a fertilizer with low concentrations of nutrients. A 6-6-6 variety is often a good choice for most gardening applications. However, for heavily depleted soil, it may be better to go for fertilizers with higher levels of essential nutrients such as a 10-10-10, a 12-12-12 fertilizer, or even a 16-16-16 fertilizer blend. 

How and When to Use Triple 6 Fertilizer

Using a triple 6 fertilizer is better for some types of plants than others. In some instances, it may be better to use a fertilizer with an unbalanced N-P-K ratio, especially if you’re looking for a certain type of growth such as fruiting or flowering varieties of plants, trees, or shrubs. 

Read on to learn more about when to use triple six fertilizer and when to opt for a different ratio.

Trees and Shrubs

While triple six fertilizer can help maintain healthy shade trees, it’s not necessarily the best choice if you’re looking for lush growth. Instead, it’s better to choose a fruit tree fertilizer with more nitrogen to encourage leafy sprouts. Most trees do best with a 6-2-3 or a 6-2-4 ratio. 

Fruit Trees

Fruiting trees need fertilizers that contain high nitrogen levels at the start of the growing season before bud development. As the season progresses and when buds begin to show, they need additional phosphorus and potassium to help with blooming, fruit production, and disease resistance.


Flowering plants need plenty of nutrient uptake to support a healthy reproductive cycle. As such, it’s important to encourage a strong, effective network of roots underground. Flowering plants tend to grow best with fertilizers containing high levels of phosphorus as opposed to balanced 6-6-6 options. For flowering species, use fertilizers with a ratio of 1-2-1.

Vegetable Gardens

Plants that produce vegetables need strong, healthy roots and protection from diseases for an optimal, healthy yield. They need plenty of phosphorus to promote flowering and fruiting during the reproductive season. It’s best to opt for a vegetable fertilizer with a higher phosphorus concentration than other nutrients.

Often, a 4-6-3 ratio is the best choice. After fruiting, you may be able to switch to 6-6-6 to maintain your plant through its dormancy and growth stages.  


Most people with houseplants are seeking to maintain the status quo. They don’t want excessive growth, as this may stress potted plants. 

Unless a houseplant is fruiting or flowering, a 6-6-6 fertilizer makes a good choice for supplying nutrients to indoor plants. With a balanced ratio of nutrients, your plant will remain healthy without putting targeted energy into either growth, fruiting, or flowering.

Lawn and Grass

Many people maintain their lawn by adding a balanced fertilizer once per year in the early spring. Doing this helps to replenish nutrients in the soil to ensure healthy growth. 

If your grass appears yellow or sparse, you may want to opt for a fertilizer with a higher nitrogen ratio instead to support strong, green, and thick growth across your lawn.

6-6-6 Fertilizer Final Thoughts

Many home gardeners rely on triple six fertilizer to maintain their yard and support healthy plant growth. A gentle, balanced fertilizer such as this one can help to restore balance to the soil without harming plants via nutrient overload. 

Whether you’re tending to shade trees or houseplants, a 6-6-6 fertilizer can help you to keep your greenery looking lush and healthy.

6 6 6 Fertilizer FAQ’s

Here is a common question often asked by home gardeners about using triple six fertilizer.