Can You Put Plant Food Spikes in Water?

Plant food spikes, also known as fertilizer spikes, are one of the most convenient ways to fertilize your plants. These spikes are a slow-release fertilizer that lasts your plants and trees a long time. But can you put them in water?

You can put plant food spikes in water, but they will take a long time to dissolve (at least 24 hours) as fertilizer spikes are designed to have low water solubility. They will also stop being slow-release fertilizers once they’re dissolved, as the water will ensure easy absorption of nutrients.

In this article, I’ll go into the characteristics of plant food spikes and the benefits of using this type of fertilizer. I’ll also explain the differences in using plant food spikes versus liquid fertilizers and how to choose the right fertilizer for your plants, so read on!

Characteristics of Plant Food Spikes

Plant food spikes or fertilizer spikes are small compressed sticks filled with the nutrients required by your plants. Most spikes are formulated to suit specific plants, which takes the guesswork and research out of determining the right formulation of NPK for your plants and trees. 

The packaging of spikes details how many spikes need to be used and how often you need to use them.

As a general rule of thumb, fertilizer spikes last between one month to six months, depending on the type of plant and when you’re applying the spikes. During the growing season, you might need to apply these spikes more frequently to supply sufficient nutrition for your plants. 

The reason plant food spikes last long is because they are a slow-release fertilizer. These fertilizers have a coating that degrades slowly, which slows down the process of nutrient release.

Slow-release fertilizers ensure that plants only have access to as many nutrients as they can use, which helps prevent wastage of fertilizer. They also limit the possibility of fertilizer burn, which is caused when plants take in more fertilizer than they can process.

Plant food spikes supply nutrients to the soil in small amounts according to several factors. The primary factor that influences nutrient release is microbial activity. Other factors include the pH values of the soil, temperatures, and moisture. 

It’s not that plant food spikes aren’t water-soluble, but their solubility is limited because of the coating on them. 

Fertilizer spikes tend to be very concentrated, with high percentages of the macronutrients (and sometimes, even the micronutrients) needed by the plants. 

This concentration is because the spikes are intended for use by the plants for a long time. Spikes designed for trees can last up to six months and therefore must contain enough nutrients to feed the plant for that time.

The concentration of nutrients is only necessary due to plant food spikes’ longevity and slow-release nature. Any liquid fertilizer made from plant food spikes will need to be diluted heavily to ensure it doesn’t burn your plants. 

How Long Does It Take Fertilizer Sticks To Work?

Fertilizer sticks or plant food spikes release nutrients into the soil slowly. This means that you’re likely to see a gradual and sustained improvement in your plants rather than sudden improvement — but how long does that take? 

Fertilizer sticks can take a week to start working and up to six weeks to effect a complete transformation in your plants. The nutrient release is determined by microbial activity, so the sticks release nutrients slowly in quantities that allow the plants to use all the nutrients available.

Because the plants can absorb the nutrients in small batches, they can use the nutrients more efficiently. You should see improvement in about a week and a full transformation in your plants after several weeks if you’ve followed the instructions on the package. 

But take care not to fall into the temptation to use too many spikes, as this could lead to excess nutrient release and fertilizer burn in your plants, leading to desiccation and even death.

Benefits of Plant Food Spikes

Fertilizer spikes or plant food spikes are an excellent way to fertilize your plants, shrubs, lawns, and even your trees. They offer several advantages, from being convenient to use to encouraging even growth. 

Here are some of the reasons you might use plant food spikes:

  • They’re easy to use. Plant food spikes are easy to use because all you have to do is hammer or place them in holes around your plants. They’ll do the rest of the nutrient dispersal work. 
  • They save time. Fertilizer spikes are usually formulated with the right ratio and concentration of NPK to last your plant the amount of time stated on the package. You don’t have to mix or blend your fertilizers differently for your plants.
  • They last long. The longevity of plant food spikes means you only have to feed your plants once a month or every two months. 
  • They don’t cause fertilizer burn. Because the plant food spikes only release a small number of nutrients at a time, your plants won’t try to take in more than they need. Supplying only the necessary nutrients prevents fertilizer burn. 
  • They improve soil quality over time. Fertilizer spikes release nutrients as a result of microbial activity, which increases the number of organisms in the soil. They also condition the soil over time, improving overall soil quality
  • They don’t lead to water pollution. Runoffs of excess fertilizer can lead to water pollution when these fertilizers enter groundwater or freshwater bodies. Fertilizer spikes prevent this by being only moderately water-soluble and releasing nutrients slowly. 

Factors Determining Usage of Plant Food Spikes vs. Liquid Fertilizers

Plant food spikes and liquid fertilizers are both good for your plants. However, each of these fertilizers has different properties for different purposes. Here are some of the factors that determine whether you would use plant food spikes or liquid fertilizers. 

  • Nutrient requirement of the plants: If your plants need nutrients immediately, like seedlings or newly repotted plants, or if your plants are already in their growing season, then you would use liquid fertilizer to make a starting solution. If your plants are mature and healthy, they’ll benefit from plant food spikes applied in early spring and late fall. 
  • Ease of application: Plant food spikes are easier to use and apply without any special equipment. They just need to be dug into the soil around your plants. Liquid fertilizer needs to be sprayed or poured carefully around the plants without getting too much at the base or on the leaves. 
  • Uniformity of nutrient dispersal: Liquid fertilizers can spread more evenly, allowing for a uniform distribution and dispersal of nutrients. Plant food spikes can concentrate nutrients in specific points around your plants, leading to focused root growth in that area. 
  • Timing of application: While plant food spikes can be applied all year long, liquid fertilizers are fast-release fertilizers. This means liquid fertilizers should only be applied during the growing season, or the nutrients supplied will be too much for your plants.  
  • Sensitivity to fertilizer burn: If your plants are especially sensitive to fertilizer burn or have already suffered fertilizer burn, slow-release fertilizers like plant food spikes are better. If your plants are hardy and tend to consume fertilizer quickly, you can use liquid fertilizer, but make sure to follow the instructions on the package. 
  • Your budget: Plant food spikes tend to be more expensive than liquid fertilizers, especially inorganic liquid fertilizers. If you simply want to feed your plants during the growing season for immediate results, liquid fertilizers are more economical. If you want to feed your plants for consistent growth, you can shell out the extra for the spikes.

Choosing the Right Fertilizer for Your Plants

Based on these differences between plant food spikes and liquid fertilizers, you can decide what would suit your plants best and use them correctly. If the growing season of your plants has already started and you want to see immediate results in your plants, you should pick a liquid fertilizer. 

You can also use liquid fertilizer as a starting solution to support your new seedlings or repotted plants to help them survive transplant shock.

However, if you plan to feed your plants consistently and want to see a gradual improvement in soil quality over time, you should use the plant food spikes. These are also easier and less time-consuming to use. 

You need to plan ahead a bit and remember that plant food spikes take time, so buy your fertilizer spikes in advance. They keep well as long as they’re stored in a cool, dry place, and you can use them throughout the year. Your plants will need more plant food spikes during the growing season than the rest of the year, so plan accordingly. 

Final Thoughts

You can put plant food spikes in water, but they’ll take time to dissolve and will turn into a fast-release fertilizer once they have broken down into the water. The liquid fertilizer you get as a result will need to be heavily diluted before use as plant food spikes have a high nutrient concentration since they’re designed for long-term use. 

Rather than putting your spikes in water, you should assess your needs and that of your plants. Then you can pick either plant food spikes or a good liquid fertilizer that suits your needs.

Alexander Picot

Alexander Picot is the principal creator of, a website dedicated to gardening tips. Inspired by his mother’s love of gardening, Alex has a passion for taking care of plants and turning backyards into feel-good places and loves to share his experience with the rest of the world.

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