The sheer variety of hydrangeas fertilizers in the market can be confusing for many of us. If you’re putting off buying fertilizer for your hydrangeas because you can’t make up your mind about which variety to choose, we’re here to help. We’ll guide you in picking the best fertilizer for hydrangeas, whatever your growing conditions may be. Whether you’re growing hydrangeas in containers, indoors, or outdoors, we’ve got you covered.
So far, we’ve tested 19 products and can authoritatively identify the best performers. For your hydrangeas, you can’t go wrong with Scotts Company Garden Pro Miracid, our Editor’s Choice, and a top option for vibrant plants and colorful blooms. A unique plant food that provides nutrients through the leaves and roots, Pro Miracid avails ingredients to the plant instantly, helping transform plants within a short time. Discover more about this fertilizer and others in our Product Review section.
Top 5 Fertilizers for Hydrangeas Review 2020
We considered things like the product weight, the types of plants the acidifier is designed for, the NPK ratio, effectiveness, and frequency of use to determine how each fertilizer performed. Later in the review, we explain why each of these factors is important and the role it plays in making the fertilizer beneficial. We’ve included a comparison table, in-detail reviews of each product, a buying guide, and a few FAQs to make it easy for you to follow along. By the end of this review, you should be able to choose the right fertilizer for your growing conditions.
Scotts Company Garden Pro Miracid – Editor’s Choice
- NPK: 30-10-10
- Weight: 4 lb
- Frequency of use: 7-14 days
- Soil acidifier: for outdoor and indoor plants
More features: roots and leaves feeding, instant work
The water-soluble Scotts Company Garden Pro Miracid is designed to feed and provide iron to your hydrangeas, and acidify the soil to make it conducive for the healthy growth of your plants. Its NPK ratio of 30-10-10 is specially formulated for strong root development and quick blooming. It’s a fast-release fertilizer that will avail nutrients to your flowers as soon as you apply it. To maximize nutrient availability, the product utilizes a double feeding mechanism where the food is absorbed through both the roots and the leaves.
For best results, apply every 1-2 weeks during the growing season. You can use the Miracle-Gro garden feeder to mix the product or use a regular watering can. If using the former, fill the feeder (with water) to the top of the label. The fertilizer comes in sleeves, which eliminates the hassle of measuring the product, so add one sleeve to the feeder and the fertilizer is ready to use. If using a watering can, add 1 tablespoon of product to a gallon of water. For indoor plants, halve the ratio such that you add ½ a tablespoon of the product to 1 gallon of water. 1.5 lbs of Garden Pro Miracid is meant to feed 600 square feet of plants, so use this to determine how much product you need for your garden. This particular pack weighs 4 lbs and is big enough for small to moderate usage.
- Double feeds through leaves and roots
- Comes pre-measured in sleeves
- Easy to use
- Requires careful proportioning, otherwise plant might have less blooms
Espoma Holly Tone – Best Organic Hydrangeas Fertilizer
- NPK: 4-3-4
- Weight: 18 lb
- Frequency of use: 45-60 days
- Soil acidifier: for outdoor and indoor plants and trees
More features: derived from feather meal, fit for spring and late fall feeding
An all-natural, organic feed designed to boost overall plant health, Espoma Holly Tone will ensure your hydrangeas develop bigger and better blooms and foliage. It’s a long-lasting product with slow-releasing action that delivers nutrients to plants over a duration of several weeks.
Holly Tone is largely derived from natural materials, including feather meal, bone meal, poultry manure, alfalfa meal, and greensand. It also contains 624 colony forming units per gram of bacillus licheniformis, bacillus megaterium, and bacillus pumilus. It’s enriched with microbes and humic acid, and contains a large amount of the patented Bio-Tone Microbes. The latter break down nutrients, making them easily available for plant uptake. They also restore soil balance, which together with the acid-boosting properties of this fertilizer, create a healthy soil environment for hydrangeas.
This fertilizer comes ready to use. Simply measure the product as advised, sprinkle around the drip line, and water. Use in the spring and late fall, and reapply every 45-60 days.
For hydrangea shrubs, add 1 cup per foot of branch spread. If the branch spread is 3 feet or bigger, use 2 cups of product. For flower beds, use 10 lbs per 100 square feet, mixing into the top 4-5 inches of soil. Use 5 lbs per 100 square feet for established beds. For new potted hydrangeas, use 2 cups of product per cubic foot of soil or 1.5 tablespoon per quart. For established potted plants, use 1 teaspoon for every 3 inches of pot diameter.
- Nutrient rich
- Long lasting
- Easy to use
- Large pack
- Strong smell
Osmocote Smart-Release Plant Food Plus – Best for Potted Hydrangeas
- NPK: 19-6-12
- Weight: 8 lb
- Frequency of use: every 4 months
- Soil acidifier: for outdoor and indoor plants
More features: granules, fits potted plants, derived from polymer-coated ammonium nitrate
Osmocote Smart-Release Plant Food Plus is a slow-releasing fertilizer derived from ammonium nitrate. It is designed to gradually feed your plants for up to 6 months. The fertilizer comes in granular form and is coated in some kind of semi-permeable resin. As the coating absorbs water, the granule soaks in the moisture, allowing the nutrients to slowly dissolve, and the nutrients are then released to the plants. The rate at which the nutrients are released for plant absorption depends on the temperature and is higher during the warm growing period. So make sure you feed your plants during the growth season – typically in early spring.
This fertilizer is a 19-6-12 NPK formulation that contains 11 essential nutrients and is designed for all growing conditions, including indoor, outdoor, and potted plants. You only need to reapply the product after 6 months. It’s easy to forget the dates; 6 months is a long time after all. You want to note your last application date on the pack so you can keep track of time and know when to reapply.
One thing you may not like about this fertilizer is the resin coating we talked about above. Once the fertilizer dissolves and is used up by the plant, the insoluble shell remains and can pose a challenge as far as disposing of it is concerned.
The pack itself is quite large at 8 lbs, and, being that you use it only twice a year, it should last a long time, particularly if you only have a few hydrangeas to tend to.
- Good for all growing conditions
- Feeds plants for 6 months
- Large pack
- Indissoluble shell
J R Peters Inc Jacks Classic Hydrangea Blue – Best for Outdoor Hydrangeas
- NPK: 7-3-3
- Weight: 1.5 lb
- Frequency of use: every 14 days
- Soil acidifier: outdoor plants
More features: contains aluminum sulfate, best applied early morning or late evening
JR Peters Inc. Jack’s Classic Hydrangea Blue is a water soluble fertilizer that is derived from ammonium sulfate and aluminum sulfate. It has an NPK ratio of 7-3-3 and is designed to boost foliage and blooming. In particular, it will enhance blue blooms in your hydrangeas and works great in both pink and blue hydrangea varieties. And while it enhances plant health in white hydrangeas, it will not change the color of white blooms.
For best results, use Jack’s Hydrangea Blue during the growth season, both when planting and at the first sights of new growth. Add 1 tablespoon to 1 gallon of water and spray all around the root zone. Reapply after 2 weeks in the first month. Thereafter, apply the fertilizer only once a month throughout the growing season. You’ll also need to apply the product early in the morning or late in the evening, taking care not to spray any of it on the leaves as this could damage them.
The packaging is excellent – a heavy-duty metal tin for safe, moisture-free storage and built-in flow control to ensure you don’t pour more product than you need. The tin has a rubberized trigger, grip, and head that make it slip-resistant. This user friendly design means you won’t waste time fumbling with the container whenever you need to use the product.
This particular pack, 1.5 lbs, is relatively small and the nearly $18 asking price makes it expensive compared to other fertilizers.
- Enhances blue flowers
- Easy to use
- Excellent packaging
Jobe’s Fertilizer Spikes – Budget Pick
- NPK: 9-8-7
- Weight: 16 oz
- Frequency of use: after each bloom shed
- Soil acidifier: outdoor plants
More features: 10 spikes, best works for roots
Jobe’s Fertilizer Spikes are derived from ammonium phosphate, ammonium sulfate, potassium chloride, and chlorine. They have an NPK ratio of 9-8-7 and are optimized to give a boost in overall plant health, foliage growth, blooming, and root development.
These slow-releasing fertilizer pouches deliver nutrients directly where your hydrangeas need it: at the roots. Two overriding benefits in using spikes are that 1) they avail the right amount of nutrients to the plant; not too little or too much, and 2) there is no chemical runoff. Use a hammer to drive the spikes into the soils, keeping them directly below the ends of the largest branches and evenly spaced around the plant, and the fertilizer will be gradually released to the plants for up to 2 months. For best results, use after each bloom shed, which is typically in late spring or early summer.
It’s important to apply the spikes around the plants, else only the side where you use the spikes will blossom. This would make this product affordable for small scale use but expensive for a large garden with many plants. Use the plant’s diameter to determine how many spikes to use per plant. The recommended ratio is one spike per 1 foot of plant diameter. If the drip line is closer than 1 foot to the trunk, apply the spikes at a distance of 1 foot from the trunk instead of at the drip line.
- Resealable, pre-measured pouches
- Easy to use spikes
- Feeds plants for up to 2 months
- Great pricing
- Not economical for large scale use
From the product reviews, you can pick out the characteristics of each product and the types of plants it is best suited for. The buying guide below will delve deeper into the specific features that distinguish one brand of fertilizer from the other. We’ll also answer a few of the most common questions we come across, and tell you how best to care for your hydrangeas.
Fertilizer for hydrangeas – is it needed?
You need to take good care of your hydrangeas, and this entails making sure they’re well fed all through the year. Fertilizer is one of the products that ensure hydrangeas have an adequate supply of all the nutrients they need to grow healthy.
Fertilizing hydrangeas guarantees lush foliage and vibrant, colorful blooms. Many fertilizer varieties are also used to enhance and often change the color of blooms (except in white hydrangeas) to blue, pink, or purplish.
Hydrangeas care advice
How do you keep hydrangeas looking healthy and strong? Well, hydrangeas don’t require round-the-clock attention, so that’s one major advantage of growing these plants. They also don’t need lots of products and supplements to blossom. Here are a few tips to help you care for hydrangeas:
Grow your hydrangeas in acidic soil. Hydrangeas do well in acidic, low pH soils. Hydrangea fertilizers are formulated to increase soil acidity, so this is something you can achieve quite easily with fertilizer and organic leftover matter from your kitchen if your soil is alkaline.
Ensure the soil is well-drained. Hydrangeas do not like poorly-drained soil. Consider using compost, mulch, or peat moss to improve soil drainage, and choose hydrangeas that do well in your growing zone.
Ensure that your hydrangeas are exposed to sunlight.
Water your hydrangeas regularly to keep the soil moist, but don’t overdo it. The secret is in keeping the soil moist, not too wet and not too dry.
Choose a fertilizer that is high in phosphorus, the element responsible for blooming in plants.
Don’t use a fertilizer that contains a high amount of nitrogen as too much nitrogen can discourage blooming.
Spread fertilizer around the drip line of your hydrangeas rather than at the base of the plant.
Prune your hydrangeas at the right time so that you don’t accidentally remove the buds, for in doing so you inadvertently impact the number of blooms.
Always follow the manufacturer’s instructions on product ratio, application timings, and application methods.
Don’t apply fertilizer during windy and rainy days since most of the fertilizer will be blown or swept away.
Watch this video for more ideas on how to care for your hydrangeas:
Features that will help you choose the best fertilizer for hydrangeas
Let’s now look at specific features in fertilizer and how you can use them to choose the best feed for your hydrangeas.
The amount of nutrients, notably nitrogen and phosphate, used to make fertilizer determine how acidic or alkaline the fertilizer is. Potassium has no effect on soil acidification.
Phosphate has the most acidifying effect on soil, so fertilizers with high percentages of phosphate will increase soil acidity by the highest margin.
Among nitrogen compounds, ammonium-based fertilizers like JR Peters Inc. Jack’s Classic Hydrangea Blue and Jobe’s Fertilizer Spikes have the highest acidifying potential compared to nitrate-based fertilizers.
The NPK ratio indicates the amount of the 3 major nutrients in the fertilizer. Choose a fertilizer with an NPK ratio that corrects the nutrient deficiency of your soil.
If your hydrangeas are yellowing and wilting, it could signify lack of nitrogen, in which case you should use a fertilizer with high nitrogen content. That means the first number in the three-number series should be the highest.
If you’re hoping to increase the blooms of your hydrangeas, choose a fertilizer that is high in phosphorus. Potassium aids in root and stem development and is crucial in keeping your hydrangeas robust and vibrant.
Hydrangeas fertilizer packs vary greatly in price. On average, it becomes cheaper when you buy the bigger packs. If you have lots of plants, you definitely want to choose one of the bigger bags, like Espoma Holly Tone or Osmocote Smart-Release Plant Food Plus, whose price is just under $20.
By contrast, small 1 or 1.5 lb bags like JR Peters Inc. Jack’s Classic Hydrangea Blue and Jobe’s Fertilizer Spikes cost roughly $17 and $12 respectively, and may make sense for someone with few plants but won’t be economical for people with large gardens.
Frequency and method of use
This varies for different fertilizers. Fertilizers like Osmocote Smart-Release Plant Food Plus and Jobe’s Fertilizer Spikes need only be applied twice a year, while Espoma Holly Tone requires reapplication after 2 months. Others require more frequent application. Scotts Company Garden Pro Miracid is applied every 1-2 weeks and JR Peters Inc. Jack’s Classic Hydrangea Blue should be applied every 2 weeks.
The main methods of application are either mixing with water and then spraying onto the soil, or mixing the fertilizer granules with soil. Few products like Jobe’s Fertilizer Spikes come in pouches that you simply push into the soil. No measuring and mixing is needed with these.
If you have plenty of plants, buy the bigger fertilizer packs so that you don’t keep reordering. They also tend to be cheaper. Smaller pack sizes cost more, but they are the more practical size if you only have one or two plants. But if you would like to take advantage of the lower price that comes with big packs, go ahead and buy these because fertilizer will keep well for years. Just make sure you store it in a cool, dry place.
Changes in the size of your hydrangeas, leaf growth, color, and number of blooms tells you that the fertilizer is working. Some fertilizers are formulated to increase the vibrancy of the existing bloom colors while others are designed to change the blooms to pink, blue, or add hints of purple. Check what the benefits of the fertilizer are as indicated by the manufacturer, and then watch out for the changes. Most fertilizers will promote 2-3 benefits.
While one of the most magical aspects of hydrangeas fertilizer is its ability to change bloom color, the fertilizer should also increase the blooms. For this to happen, the fertilizer needs to have a high amount of phosphorus. Read the label to see if a boost in blooming is among the indicated benefits. You can also read the ingredient list to see how much phosphorus it contains. Bloom enhancers with high phosphorus amounts include Scotts Company Garden Pro Miracid, Espoma Holly Tone, and Jobe’s Fertilizer Spikes.
Hydrangeas should be fed during the growth season. This is typically in early spring, and in some cultivars, late summer. Choose a slow-release fertilizer that will supply the plant with little amounts of nutrients over time since hydrangeas do not require a lot of fertilizer. Most fast-release fertilizers for hydrangeas are most effective when used during early spring and mid-summer. More importantly, follow the feeding times indicated in the fertilizer because the times may differ for different fertilizers.
Not necessarily, but a landscape with beautiful blue flowers never hurt the eyes. Plus, having random blue blooms in the midst of the more common white, pink, purple, and red hues in most flower gardens will add to the beauty of your yard. The secret to getting blue hydrangea flowers lies in increasing the acidity of the soil (lowering the pH), and use of fertilizer is one way to do this.
Yes. Coffee grounds are rich in nitrogen, which promotes foliar growth. They also boost acidity in the soil, making it easier for plants to absorb the aluminum that’s in the soil, leading to blue blooms.
In addition to providing nutrients, eggshells can help your hydrangeas develop pink blooms. This happens because when they break down, egg shells reduce acidity in soil. When the soil pH is high, hydrangeas do not absorb aluminum easily. The lack of aluminum causes the plants to yield pink blooms.
Our top choice is Scotts Company Garden Pro Miracid. We like that you can use it on both indoor and outdoor plants, and that plants can absorb the ingredients through both leaves and roots. We also like how the nutrients are instantly available for the plant, and it won’t be long before you see change in your plants.
Our second choice is Espoma Holly Tone. The biggest plus points for this product are its organic nature and high microbes content. Others are its slow-releasing mechanism that avails nutrients to the plant for up to 8 weeks and the ready-to-use granular format that only needs to be sprinkled onto the soil.
Our third best fertilizer for hydrangeas is Jobe’s Fertilizer Spikes, a product that delivers nutrients directly to the roots. We like its slow-release action that supplies plants with nutrients for up to 8 weeks. And we especially like the pre-measured spikes it comes in, which means less work for you.