The Best Fertilizers for Flowers: The Ultimate Resource


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Flowers require sufficient nutrients to grow and bloom. We all love the pleasant view of vibrant flowers and their tantalizing scents in our front or back yards. However, you could be looking for the best fertilizers to nourish your flowers, enabling them to bloom during their growing season.

The best commercial fertilizers for flowers include Bayer Advanced Rose & Flower, Miracle-Gro Soluble Booster, and Jack’s Classic Bloom Booster. But you can use many organic substances to make a homemade flower fertilizer, including fish waste, vegetable scraps, and bone meal.

This article explores several topics related to fertilizers for flowers. Read on to learn the best fertilizers for flowers, how to apply them, and how to prepare homemade fertilizers.

The Best Commercial Fertilizers for Flowers

Identifying the best fertilizer for your flowers with numerous fertilizer brands and products in the market can be challenging. You should ensure that the ideal fertilizer matches your flowers’ nutritional needs according to the soil test’s recommendations discussed later in the article. 

And I’ve compiled some of the best commercial fertilizers for flowers below:

BioAdvanced Bayer Rose & Flower Care

This fertilizer is a 3-in-1 product since it serves as a:

  • Fertilizer – contains the three macronutrients
  • Insect killer – kills pests, such as aphids, Japanese beetles, and leafminers
  • Disease control – protects plants from Powdery Mildew, Black Spot, Southern Blight, and Rust

With an NPK ratio of 6-9-6, this fertilizer promotes flowering while ensuring that your plant’s leaves and stems remain healthy. Moreover, it protects your flowers from pests, making them cost-effective.

Bayer’s Advanced Rose & Flower Care is available in granular and liquid (concentrate) forms. The granular type is ideal for farmers who want a slow-releasing fertilizer that won’t require frequent application. So, you can apply it every six weeks during the growing season.

The product is perfect for various flowers, including:

  • Roses
  • Hibiscus
  • Iris
  • Rhododendrons
  • Azaleas Camellias.

JR Peters Classic Bloom Booster

It is a water-soluble flower food comprising macro- and micro-nutrients. With an NPK ratio of 10-30-20, this fertilizer is a bloom booster that promotes flowering. And adequate potassium levels ensure your flowers have strong roots.

Jack’s Classic Bloom Booster comes with a measuring spoon, ensuring easy and safe application. Plus, you can apply it both as a foliar and roots fertilizer. 

Since Jack’s Bloom Booster is Multipurpose, you don’t have to go for another fertilizer for your veggies and other flowering plants. Hence, you can also use it on:

  • Tomatoes
  • Eggplants
  • Blueberries
  • Watermelon
  • Okra
  • Citrus fruits.

Miracle-Gro Water Soluble Flower Food

This water-soluble fertilizer is ideal for flowers that require an instant boost to form thriving blooms. Hence, it has an NPK ratio of 10-52-10. And you’ll notice quick results after applying it every 7 to 14 days.

It’s perfect for actively growing annual and perennial plants. You can apply it via a garden feeder or using a watering can.

Moreover, Miracle-Grow has another flower fertilizer suitable for other plants. The multipurpose fertilizer has an NPK ratio of 24-8-16, making it ideal for plant growth and development.

So, be keen on the NPK code on the product’s label to ensure you have the best-suited fertilizer to meet your flowers’ needs.

Best Alternatives to Popular Commercial Fertilizers

Commercial fertilizers, especially from popular brands, aren’t always the best option despite being effective. For starters, they’re way more expensive than products from smaller brands. Furthermore, they might be overrated since they’re famous and do not deliver the expected results.

Hence, looking for alternative fertilizers for your plants can be practical. Most of them are cheaper and have outstanding results. Moreover, you can opt to prepare your preferred flower food at home.

Let’s look at these alternative fertilizers:

Element Nutrients Bloom Booster

This fertilizer is perfect for flower gardens as it comprises more than 40 ingredients, including natural nutrients. It is a hydroponic-grade bloom booster that works perfectly on various growing mediums. With an NPK ratio of 1-34-32, this fertilizer boosts blooming and protects against diseases.

But it’s best to confirm if it’s allowed in your state due to the high phosphorus concentration (phosphorus runoff affects water quality).

Flower Fuel is available in a 250g (8.7 oz) tin and can treat 200 gallons (909 liters) of water. So, it’s a cost-effective fertilizer. Moreover, it is easy and safe to use.

You can add ¼ tsp of the fertilizer per gallon of water and use it alongside a base nutrient.

Down to Earth Rose & Flower Mix

It is a natural fertilizer that’s best suited for potting mixes. It contains 4%N, 8%P, and 4%K, to enhance vibrant flowering. Comprising organic matter, including bonemeal and kelp meal, Down to Earth Rose & Flower Mix is perfect for organic gardens.

It’s available in 1-pound (0.45-kg) and 5-pound (2.27-kg) biodegradable packets. Moreover, it’s safe to use and cost-effective.

You can apply it to the following plants throughout their growing period:

  • Flowers – such as roses
  • Bulbs – onions and garlic
  • Flowering shrubs.

Make Homemade Fertilizers for Flowers

Organic homemade fertilizers are the perfect alternative when you want to save money and protect the environment. You can use various ingredients to prepare a flower fertilizer at home. You only need to identify what your plants require, and you’re good to go.

The only challenge is determining what nutrients are in a specific raw material and their content.

Here are the most common ingredients to use to make homemade fertilizers for flowers:

  • Leftover vegetables: You’ll not throw away your veggie scraps when you have an organic flower garden. These leftovers contain lots of nutrients that could boost your flowers’ health. You can add Epsom salt and ammonia to your veggie scraps and dissolve them in water to make organic fertilizer.
  • Fruit peels: They’re also nutrient-rich. For instance, pomegranate rinds have potassium, phosphorus, magnesium, calcium, and several micronutrients. Soaking these peels in water for about two days makes an excellent organic fertilizer. 
  • Egg shells: These contain a high calcium and potassium quantity. And they’re ideal for outdoor flowers.
  • Compost tea: It’s a blend of organic materials brewed to make fertilizer. It contains beneficial microorganisms that one extracts from compost. Plus, you can tweak the ingredients to achieve the desired result.
  • Bone meal: It is a phosphorus-rich organic substance containing ground animal bones and slaughterhouse wastes. So, it’s perfect when you want to neutralize your soil if it has high nitrogen and potassium concentrations.
  • Seaweed: It contains essential nutrients your flowers need to grow and flourish. It makes an effective all-purpose fertilizer, and it’s easy to prepare.
  • Fish wastes: These help in preparing nutrient-rich fish emulation.

Check out my article about 10 cheap fertilizer alternatives that do an amazing job.

How To Prepare a Homemade Fertilizer for Flowers

  1. Add ½-part dolomite lime, four parts seed meal, ¼ part gypsum, and ¼ part agricultural lime into a container.
  2. Add ½ part kelp meal and 1 part bone meal.
  3. Close the container tightly and shake it vigorously.
  4. Store the airtight container in a dark, cool room for a few months.
  5. When ready to use, sprinkle the powdered fertilizer on the soil in your flower garden. Use 4 quarts (3.2 kg) of fertilizer per 100 square feet (9.29 square meters).

What To Look For in a Flower Fertilizer

Since there are different types and fertilizers, you could wonder what to look for in a fertilizer. For starters, the ideal fertilizer must:

  • Meet the nutritional requirements of your flowers.
  • Have a suitable NPK ratio.
  • Be appropriate for your soil’s texture.
  • Be compatible with the soil’s pH.
  • Be easy to apply.

That said, it’s essential to know what your flowers require precisely to identify the best fertilizer to apply. For instance, you can consider using a nitrogen-based fertilizer if the soil test results indicate nitrogen deficiency. I’ve written an in-depth article about fertilizers high in nitrogen, that you can find here.

Nitrogen promotes vegetative growth, enabling healthier leaves and stems. However, flowers don’t need too much nitrogen since it hampers flowering.

On the other hand, you might go for a phosphorus-rich fertilizer if a soil test indicates that the soil is deficient in this macronutrient. Plus, you’ll consider this type of fertilizer if you want flowering plants to bloom.

However, in most cases, a complete fertilizer is the most practical choice since it contains the three essential primary nutrients. But it’s vital to consider the NPK ratios since too much of one of the macronutrients can have detrimental effects.

Moreover, a soil test can reveal that your soil is too acidic (pH less than 5.7). In such a case, it would help to add lime to the soil to neutralize the acidity. 

What Are the Best Npk Ratios for Flower Fertilizers?

NPK ratios refer to nitrogen, phosphorus, and potassium proportions by weight in fertilizers. The ratios vary among fertilizers; most manufacturers indicate this on the labels. Now, what are the best NPK ratios for flower fertilizers?

The ideal NPK ratios for flower fertilizers depend on their needs. For instance, 10-10-10 is best for flowers requiring three macronutrients for optimal growth and production. On the other hand, 5-10-5 is the most suitable ratio for powering flowering.

So, how do you interpret the NPK codes on your bag of fertilizer?

If the code on a 10-pound (4.54-kg) bag of fertilizer is 10-10-10, the ratio of the three macronutrients is 1:1:1. Hence, the fertilizer contains 1 pound of each element. And the rest of the weight comes from other ingredients.

Getting a fertilizer with the same NPK ratio as recommended by the soil test is essential. However, you may not always find one that matches these proportions. So, you can look for a fertilizer whose NPK ratio is close to the required proportions.

Types of Fertilizers for Flowers

Having established that flowers need fertilizers, it’s essential to know what types of fertilizers would be best for your flowering plants. Generally, we can categorize fertilizers into two groups, complete (or all-purpose) and simple fertilizers.

Complete Fertilizers 

These fertilizers comprise the three macronutrients that plants require (NPK). Hence, you’ll find the elements’ ratios on fertilizer labels, for example, 15-10-10. But these fertilizers also have filler ingredients to increase the weight, such as powdered clay or limestone.

According to the University of Massachusetts Extension, complete fertilizers are ideal for fertilizing plants. These fertilizers have a combination of macronutrients that promote healthy plant growth and development.

But, it’s safe to understand that complete fertilizers for flowering plants contain high amounts of phosphorus. Phosphorus is present in most soils, so it would help if one doesn’t apply too much of it to flowers.

Although phosphorus promotes flower formation, an excessive application has adverse environmental effects such as:

  • It can be toxic to beneficial microorganisms in the soil.
  • The runoff containing phosphorus can end up in water bodies, affecting water quality.

Simple Fertilizers

Simple fertilizers comprise one standalone macronutrient. Therefore, they’re perfect for plants experiencing single-element deficiencies. For instance, your plants could lack nitrogen.

Therefore, you can purchase a nitrogen-based fertilizer to supplement it in the soil. Moreover, these simple fertilizers can either be synthetic or organic. Other examples include:

  • Urea—contains nitrogen.
  • Mineral phosphate—has phosphorus.
  • Potash—contains potassium.

Here are other types and forms of fertilizers:

Chemical Fertilizers

These products are artificial fertilizers comprising a combination of inorganic substances such as magnesium nitrate or ammonium phosphate. They’re readily available in agro-based retail shops or online stores. Many farmers opt to use these synthetic fertilizers since they’re easy to apply. However, these chemicals can adversely affect the plants, gardener, and environment if overused.

Organic Fertilizers

They’re natural substances from plants or animals that contain essential nutrients. The world is shifting to organic fertilizers since they’re bio-friendly and cost-efficient. Organic fertilizers spare the beneficial insects and protect the environment from harmful chemicals. However, it’s not always easy to formulate them since you need to determine the number of nutrients in the ingredients.

Foliar fertilizers

These are fertilizers specially made for foliage (leaves) and you spray them directly on the leaves and not into the soil. They help promote healthier leaf growth and contain nutrients that plants can absorb through the leaves. However, this option is less effective on thick, waxy textured plant leaves. 

Granular Fertilizers

They are fertilizers in solid form—mainly as pellets or granules. They’re slow-releasing fertilizers, making it unnecessary to apply them frequently. This option is great for gardeners who may not have much time to spare to fertilize their garden often. However, plant roots take longer to absorb than liquid fertilizers.

Liquid (water-soluble) fertilizers

These are solutions containing water-soluble nutrients. You can buy them as powders (and dissolve them in water) or as concentrated solutions (dilute them). Although plants absorb them readily, you have to reapply them frequently making this option more time-consuming. 

Do Flowers Need Fertilizers?

You might wonder what flowers need to grow healthy and vibrant if you’re a newbie in flower gardening. Like all plants, flowers require water, fertile soil (or growing medium), warmth, and sunlight. However, plants might deplete nutrients in the ground and air during their growing season, especially if the garden has been tilled continuously for several seasons.

Flowers need fertilizers since they might not always acquire a continuous supply of nutrients from the soil. And these nutrients are essential during budding and blooming at the peak of the growing season. 

The soil could be deficient in essential nutrients due to:

  • Human activities like monocropping, intensive farming, and land development deplete the soil.
  • Soil type or texture—sandy soils are low on nutrients.
  • Leaching.
  • Soil erosion.
  • Soil pH
  • Lack of nutrients in a specific region.

Fertilizers come in handy when replenishing or supplementing your flowers’ source of nutrients. Essential elements enable plants to make food and obtain enough energy to carry out various physiological processes. 

Like most plants, flowers grow and flourish when they obtain the following categories of nutrients:

Primary (Macro-) Nutrients

These are elements that flowers require in significant amounts. They help the flowering plants grow and perform essential functions. Hence, a deficiency in these nutrients would have a toll on the flowers, resulting in stunted growth or consequential death.

Macronutrients that flowers require include:

  • Nitrogen (N): It’s a vital element that enables plants to manufacture amino acids (protein building blocks), chlorophyll (the green pigment in leaves), and enzymes. Nitrogen also helps in promoting fruit and seed development.
  • Phosphorous (P): This essential nutrient enables plants to form roots and flowers. Phosphorus is also vital in processes such as respiration and photosynthesis. Plus, it helps manufacture DNA and RNA structures, enabling the transfer of genetic information.
  • Potassium (K): Another crucial element, Potassium is helpful in plant growth since it boots the functions of enzymes—which accelerate metabolic processes. It also helps flowering plants resist disease and form flowers, fruits, and seeds.

Secondary Nutrients

These are elements that plants don’t need in large amounts, but their deficiency slows down a plant’s growth and development. In severe cases, a lack of these nutrients may cause dases. 

They include:

  • Magnesium (Mg): Helps in chlorophyll production and healthy leaf growth. Moreover, Magnesium activates some plant enzymes.
  • Calcium (Ca): It helps build some cell structures, such as cell walls and membranes. It’s also a secondary messenger in metabolic and physiological processes.
  • Sulfur (S): It helps form proteins, chlorophyll, enzymes, and some proteins. Moreover, sulfur boosts a plant’s winter hardiness.

Trace (Micro-) Nutrients 

These are elements that plants need in small amounts. But they have essential functions just like the primary and secondary nutrients. And they include:

  • Manganese
  • Zinc
  • Molybdenum
  • Cobalt
  • Sodium
  • Nickel
  • Iron
  • Copper
  • Boron.

How To Know if Your Flowers Require Fertilizers

Fertilizers only supplement the missing nutrients your flowers need to grow. Flowers will exhibit some symptoms if facing nutrient deficiencies. Hence, it would help to apply fertilizers after noticing these signs in your plants.

And they include:

  • Yellowing of leaves (chlorosis): Nitrogen and potassium deficiencies
  • Stunted growth: Nitrogen and potassium deficiencies
  • Reduced flowering: Phosphorus and Molybdenum deficiencies
  • Weak stems: Potassium and Calcium deficiencies
  • Brown leaf tips: Calcium deficiency
  • Cupped or wrinkled young leaves: Calcium deficiency
  • Yellowing in between leaf veins:  Magnesium deficiency
  • Stiff, thin, woody stems: Sulfur deficiency
  • Interveinal chlorosis (dying tissues in between leaf veins): Iron deficiency

Although the above symptoms can indicate nutrient deficiencies, they may not always accurately determine what nutrients your flowers could lack. 

Therefore, it would be best to carry out a soil test in your flower garden or raised beds to identify the specific nutrient deficiency in your flowers. The best option for this procedure would be to take a sample of your garden soil to a reputable laboratory and let the experts test the soil for you.

The test results will indicate if your soil is okay and what specific nutrient is lacking. And the experts will advise you on the best fertilizer type to apply. 

Another alternative would be to carry out the soil test yourself. Although this isn’t the most effective option, it can also inform you about your soil’s status. So, you can use it as a prerequisite procedure before seeking the services of a professional soil analyst.

And you’ll find a wide array of soil testing kits to make your measurements.

I recommend the Luster Leaf Digital Soil Test Kit (available on Amazon.com). It’s an easy-to-use device that tests various soil parameters, including pH and nutrient levels. Therefore, it will let you know if your soil has a nitrogen, phosphorous, or potassium deficiency.

When Is the Best Time To Apply Fertilizers on Flowers?

The best time to apply fertilizers to flowers is before or shortly after planting them. Then, depending on the type, you can reapply the fertilizer, following a fixed schedule. However, following an expert’s or manufacturer’s guidelines is crucial.

Here’s a breakdown of when to apply fertilizers to flowers:

  • Annuals: Apply fertilizer when preparing the flower bed and a second time in 6 – 8 weeks. You can reapply a third time if the flowers bloom during fall.
  • Perennials (New plants): Apply the fertilizer during flower bed preparation and after 6 -8 weeks.
  • Perennials (Established): Fertilize in spring when growth resumes and after 8 weeks if they bloom in fall.
  • Roses: Apply fertilizer in May, June, and early July.   
  • Wildflowers: These have few fertilizer requirements, but you can apply fertilizer once during spring.

Here’s a YouTube video that explains why and how to fertilize flowers on hanging baskets:

How To Determine the Right Fertilizer Amount for Your Flowers

The amount of fertilizer to apply depends on the size of your flower bed. Moreover, the type of flowers you’re growing can determine this quantity. However, you’ll find the recommended amount for synthetic fertilizers on the products’ labels.

Moreover, you can consult a soil expert, especially if applying organic fertilizers. After conducting a soil test, you can calculate the amount of fertilizer to use by following the steps below:

  • Measure the area of your flower garden (or raised beds).
  • Calculate the amount of fertilizer to apply per square meter.
  • Apply the fertilizer as required.

Final Thoughts

Native flowers may not require fertilizers since they’re hardy. However, most flowers need supplementary nutrients to promote healthier growth and development.

Many synthetic and organic fertilizers are available in the market. Hence, determining what your flowers require is crucial before you settle on the ideal fertilizer.

And a soil test is beneficial in determining what nutrients your flowers specifically need.

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Lars

I am always happy to share all my knowledge about how to keep your garden in good condition and make it special.

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