Liquid plant fertilizer is known for being one of the most quick-acting, effective fertilizers on the market. For fast-growth and super-boosted nutrients, liquid fertilizer is the way to go, but it must be applied correctly.
To use liquid fertilizer, follow these steps:
- Prepare the soil for fertilizer application.
- Determine how much liquid fertilizer your plant needs.
- Choose an application method.
- Apply the fertilizer gently.
- Allow it enough time to soak in.
- Water the plants and soil.
- Continue a consistent application routine.
- Apply liquid plant fertilizer in the spring and fall.
The rest of this article will go into more detail about each of these tips for using liquid fertilizer successfully. I’ll also explain which plants benefit the most from liquid fertilizer.
1. Prepare the Soil for Fertilizer Application
Before applying liquid plant fertilizer to your garden or lawn, it’s best to prepare the soil. Getting the soil ready ahead of time encourages healthy absorption and prepares the plants for receiving the essential nutrients.
To prepare the soil, you’ll want to liberally water it around one to two days before you apply the fertilizer. Hydrating the soil well softens the earth and opens it up for successful nutrient absorption.
Because foliar liquid fertilizer is first absorbed by leaves and foliage, it’s crucial to ensure that the plant is well-hydrated as well. A sufficient water supply supports the plant in being able to absorb all of the fertilizer and improves its ability to move the nutrients throughout the plant system.
If your area is experiencing heavy rainfall for an extended period with unpredictable weather conditions, you might want to delay your fertilizer application until the weather stabilizes. Too much rain can cause compaction, so you must check your soil and prepare it accordingly before applying your fertilizer.
There is one exception: If you’re applying the liquid fertilizer directly into the soil as part of your watering session, you don’t need preliminary preparations for your soil. You just have to dilute the fertilizer to half strength (half the recommended dosage) using the typical amount of water you use during a regular watering session.
Pour the fertilizer solution slowly into the soil around the base of the plant to ensure the nutrients get to the roots.
2. Determine How Much Liquid Fertilizer Your Plant Needs
Applying the correct amount of liquid plant fertilizer is essential for successful nutrient integration. You don’t want to overwhelm your plant by using too much, but you also don’t want to apply too little and yield zero results.
To calculate the most beneficial amount of fertilizer for your plants, you’ll first need to conduct a soil test. Testing the soil should always be a priority before applying any type of fertilizer, especially liquid fertilizer, because of its quick-acting benefits.
At-home soil tests are easy to use and should produce results rather quickly. I recommend the MySoil Soil Test Kit (available on Amazon.com). This kit is simple, even for first-time gardeners, and will give you detailed recommendations for nutrient needs along with your results.
These results will help you determine what nutrients your soil needs and how much fertilizer you should apply. After submitting your soil sample, you’ll have access to accurate results online within just 6 to 8 days.
After testing the soil and reviewing your results, you should have a good idea of what nutrients are present in your soil, as well as which ones are lacking.
If your soil test indicates a deficiency in nitrogen, for example, you should choose a liquid plant fertilizer with high nitrogen content. The manufacturer’s recommendations on the product should indicate the ideal amount of fertilizer to use for the size of the garden or lawn you’re treating.
To err on the side of caution, most gardeners dilute liquid fertilizer at half-strength, as it helps prevent the adverse effects of over-fertilization. This technique works well for most plants unless you have a heavy fertilizer feeder in your garden.
3. Choose an Application Method
Liquid plant fertilizer is highly versatile when it comes to application styles. You can choose to apply your liquid plant fertilizer in whichever way works best for your unique gardening needs.
Many indoor plants have sensitive leaves that can get damaged when wet or moist for extended periods. One example is the African violet, which can get water-soaked lesions on the leaves from water droplets.
Therefore, it’s important to understand your plant’s needs before deciding how to apply the liquid fertilizer.
Some of the most common ways liquid plant fertilizer is distributed include the following:
Misting or Spraying
One option is to mist or lightly spray with a spray bottle or handheld fertilizer spreader. Ideal for smaller areas, a handheld spray bottle is a great way to gently apply small amounts of fertilizer without overwhelming your plant.
Because you have to spray it manually, this can become tiring in large spaces, but this is a great option when fertilizing small gardens and potted plants.
Sprayer or Spreader
You can also spray with a liquid fertilizer sprayer. A liquid fertilizer spreader comes with a spraying hose and a fertilizer compartment.
This is an excellent option for medium-large spaces, as the nozzle can spray continually, and the fertilizer compartment can often be worn over the shoulder or backpack-style.
You can read more about how to choose a fertilizer spreader in my other article, where I discuss the different types of spreaders: Do You Need a Fertilizer Spreader? How to Decide
Standard Garden Hose Nozzle Attachment
Some fertilizer sprayers can be hooked directly onto the nozzle of your garden hose, creating a powerful, fully adjustable sprayer. This option is great because it’s hose-powered, so you never run out of water.
Added to Water
You could also water it in with your regular watering session. Many in-ground plants require about 1-inch (2.5 cm) of water per week. You can dilute the fertilizer with your regular amount of water per plant for light applications.
If you’re worried that most of the fertilizer will be leached quickly below ground, you can use half the regular amount of water (with half-strength fertilizer) and ensure the roots soak in the nutrients first. After 2-4 hours, you can add the remaining water requirement free of fertilizers.
Injected Near the Roots
Finicky plants that don’t like wet leaves prefer fertilizers injected into the soil close to their roots for easier absorption. If you have these plants, you must not use a spray bottle or a garden hose when applying liquid fertilizer.
Once you have settled on an application method appropriate for your garden space, you’re ready to apply the liquid plant fertilizer.
4. Apply the Fertilizer Gently
Liquid plant fertilizer is an excellent option for gentle fertilizer application. Because it’s usually applied with foliar techniques, it settles gently on the plant, absorbing naturally into the leaves before it’s washed into the soil and absorbed by the roots.
It’s important to make sure fertilizer application occurs on a dry, clear day with little to no wind. Severely windy days and rainfall can negatively affect the distribution of the fertilizer. Choose a mild day, and apply the fertilizer early in the day, ideally at least 2 hours before sunrise, to give it plenty of time to soak in.
Each fertilizer type will have its own application recommendations from the manufacturer you can review and follow accordingly. Typically, you simply spray an even layer of foliar fertilizer over the plants you’re treating and leave it to soak in.
On the other hand, you must apply some liquid fertilizers directly to the soil and avoid the leaves to prevent leaf damage. Either way, you must apply them gently, carefully, and thoroughly to maximize their benefits.
5. Allow It Enough Time to Soak In
Liquid fertilizer needs ample time to soak in after application. At a minimum, you should allow the fertilizer to rest for 2 to 4 hours, but it shouldn’t be left without water for more than 24 hours.
Watering too soon after application can prematurely wash the fertilizer away and prevent it from fully soaking into the foliage of the plant and delivering all of those essential nutrients.
At least 2 hours is usually a sufficient amount of time for fertilizer to soak in if it’s a mild-to-warm day. As stated above, you can typically leave the fertilizer on the plants for up to 24 hours, but if you leave it any longer than that, the fertilizer can actually burn the plants.
It’s best to apply the liquid fertilizer in the morning or early in the evening. Doing so will provide your fertilizer ample time to work its way through your plants and deliver essential nutrients.
Too much heat and sunlight can initiate chemical reactions in the liquid that can damage your plant’s foliage. Therefore, it’s crucial to apply liquid fertilizer when the sun is less intense.
Gardeners typically water plants early in the morning to allow the roots to absorb enough water before the moisture is lost through drainage or evaporation.
However, some plants don’t need daily watering, especially on a cool and less sunny day. In that case, you can apply the liquid fertilizer before sunrise on the day of your next watering schedule. That way, your plant has enough time to absorb the nutrients from the fertilizer.
6. Water the Plants and Soil
Watering the plants and soil is an important step in using liquid plant fertilizer, as it washes the fertilizer off of the leaves, preventing burning, and gives it a second round of nutrient delivery through the soil.
You can use a sprinkler system, manual sprinkler, garden hose, or a watering can to wash the fertilizer off the plants. As it drips off the leaves and into the soil, the remaining nutrients are absorbed into the ground and travel to the root systems of the plants.
This process is incredibly helpful because the plants receive nutrients through their leaves and their roots, supporting them with healthy nutrients from both directions.
Alternatively, you can apply the liquid fertilizer the night before a predicted rainfall. This depends on the expected amount of rain. For instance, a light rain shower can help work the fertilizer down to the root zone.
However, if you’re expecting a heavy downpour, you might as well skip the liquid fertilizer. Heavy rain will wash the fertilizer away too quickly, wasting valuable resources. That’s why it’s essential to check the weather forecast in your area, especially when dealing with outdoor plants.
On the other hand, indoor potted plants aren’t affected by rainfall. In that case, you can water them lightly after applying fertilizer.
Be mindful of your plant’s watering needs, as several houseplants don’t like getting their leaves wet. Otherwise, they’ll be more susceptible to microbial diseases and pest infestation.
These plants prefer the liquid fertilizer applied directly to the soil. Therefore, you don’t need to mist the leaves to wash away the fertilizer.
7. Continue a Consistent Application Routine
Applying liquid plant fertilizer should not be a one-and-done thing during fertilizer season. Developing a consistent application routine will be the best way to support your plants and provide them with ample nutrients throughout the entire growing season.
Once you apply liquid plant fertilizer, the nutrients go right to work, soaking into both the foliage and the soil, but their effects usually only last up to two to three weeks. Because this type of fertilizer is gentle, light, and quick-acting, you can continually apply it without damaging your plant.
The recommendation is usually to reapply a light coat of fertilizer every 2 to 3 weeks to keep the nutrients coming. If you apply once and never again, your plants can actually go into shock from a lack of nutrients. They receive a sudden burst of nutrition, and then as the effects fade away, the plant begins to suffer without those nutrients to rely on.
If you apply consistently, you can avoid this shock reaction. As the fertilizer season comes to a close, spread your fertilizer applications out farther and farther, gently reducing the number of nutrients applied so the plant can ease off of the fertilizer instead of losing its benefits from an abrupt halt.
8. Apply Liquid Plant Fertilizer in the Spring and Fall
Choosing when to apply liquid fertilizer is important, as the timing of application directly affects the plant’s ability to grow and thrive.
Spring is the ideal fertilizing season, usually from March to late June. You should wait until the final freeze of the winter has thawed and then apply the first round of fertilizer. After that, you can continue your regular fertilizing schedule until late June.
Avoid fertilizing your plants during the summer. While you may think that keeping your plants well-fertilized during the hot summer months is a good idea, doing so will encourage new growth.
This would normally be a good thing, except that the new growth will be damaged by the coming cold months. You can, however, do a light round of fertilization in the fall, right before the cold winter months.
Applying one last, late-season application of liquid plant fertilizer before the winter begins will give your plants the nutrients they need to survive the dormant, cold season and to come back flourishing when the spring season arrives again.
Which Plants Benefit the Most?
Liquid plant fertilizer tends to be reasonably all-purpose, benefiting nearly all types of plants.
It’s particularly useful in:
- Landscaping, specifically grass lawns
- Perennial and annual flowers
- Young and old fruit trees
- Vegetable gardens during the growing season
- Newly planted flora still acclimating to their environment
- Fast-growing plants that need extra nutrient support
Fruit and vegetable gardens are particularly good candidates for liquid plant fertilizer, as they’re in full-on production mode throughout the entire spring season. These plants rely on the nutrients delivered by the liquid plant fertilizer to cultivate their numerous healthy, robust fruits and vegetables.
Grass lawns benefit highly from liquid fertilizer, as it soaks into the grass blades and the soil, creating a healthy growth environment. Not only that, but grass lawns can be cumbersome to fertilize, especially when they’re expansive. Liquid fertilizer is easy to apply and can often be done more quickly and thoroughly than other granular options.
Some Plants Don’t Do Well With Fast-Acting Fertilizer
While liquid plant fertilizer can typically be used on any plant, there are some plants that wouldn’t benefit from the fast-acting nutrient boost liquid fertilizer provides. Some plants, like Japanese maple trees and other slow-growing plants and trees, can be damaged when they’re encouraged to grow too fast.
When using liquid fertilizer, always make sure the nutrient content matches the needs of the plant. Test the soil, research the plant, and then choose a fertilizer accordingly. In some cases, a plant may not need to be fertilized at all—in which case, a liquid plant fertilizer would not be necessary.
If you’re interested in keeping your plants healthy, you know that fertilization is only one of many things you need to do. Salt injury is another risk you should be careful about. I’ve written about this in a complete guide: Can Plants Survive if They Get Salt on Them?
Liquid plant fertilizer is one of the most effective and fast-working fertilizers on the market. It’s a great choice for a wide variety of plants with its gentle, all-purpose nutrient supply.
When using liquid plant fertilizer, you should either:
- Lightly spray the foliage to allow for foliar absorption.
- Pour the solution directly into the soil for root absorption.
If using the foliar method, be sure to rinse after it has dried so the remaining fertilizer doesn’t burn the foliage and can be flushed into the soil for further nutrient support at the root level.