Skip to Content

15 Best Fertilizers For Black Eyed Susans [When And How To Apply]

Black-eyed Susans are a hearty flower that not only grows in the wild but can add a beautiful swath of yellow to your garden. You may be wondering what the best fertilizers are for this flower. We've thoroughly investigated the available information and have some recommendations for you.

Black-eyed Susans are easy to grow since they don't need special treatment. In good soil, they may not need fertilizer at all.

Go lightly if you choose to fertilize your flowers with gentle natural fertilizers. Here are our top 15 fertilizers for black-eyed Susans.

  1. Kitchen Waste Composted With Bokashi
  2. General Hydroponics Flora Series
  3. Miracle-Gro Plant Nutrition Granules
  4. Miracle-Gro Performance Organics Blooms
  5. Epsoak Epsom Salt
  6. Osmocote Smart-Release Plant Food
  7. SUPERthrive The Original Vitamin Solution
  8. FoxFarm Liquid Nutrient Trio
  9. DR EARTH Flower Girl Bud & Bloom Booster
  10. Organic Kelp Fertilizer by GS Plant Foods
  11. Jobe's Organics Organic Fertilizer
  12. Nelson Plant Food
  13. Scotts Super Bloom Water Soluble Plant Food
  14. Incredible Bulk Vegan Plant Food
  15. Simple Grow Worm Castings

That's quite a list! We'll go into each fertilizer and discuss why it may be the right choice for your flowers. Keep reading as we cover when and how to fertilize Black-eyed Susans and even which fertilizer will prolong the life of cut flowers.

Beautiful Black-Eyed Susans flower on a garden and bokeh background texture. - 15 Best Fertilizers For Black Eyed Susans [When And How To Apply]

1. Kitchen Waste Composted With Bokashi

A bucket filled with bokashi. This photo is taken under the process of collecting food waste in the kitchen. Bokashi is a type of fermented wastemanagement.

Since Black-eyed Susans do well in many types of soil and require minimal feeding, it is possible to over-fertilize them. Doing so can cause weak, damaged stems.

The best fertilizer for these flowers may be your kitchen waste. Though the flowers may not need much fertilizer, they do well with organic materials.

Bokashi is fermented bran that is used in a variety of ways. The liquid from composting a large amount of bokashi is called bokashi tea. This tea is too acidic to use alone.

To use Bokashi for flowers, put it in the middle of your compost pile to get rich compost in as little as ten days. This kit can get you started.

See an indoor composting kit on Amazon.

2. General Hydroponics Flora Series

The Flora Series from General hydroponics is a nutrient system that uses three components to support your plants from seed to flower. It is versatile and can be used for indoor and outdoor plants.

If you choose to use a fertilizer like this, you'll want to use it sparingly for Black-eyed Susans, only one or two times a year during the growing season.

See this liquid fertilizer system on Amazon.

3. Miracle-Gro Plant Nutrition Granules

Miracle gro plant food is on display in the garden section of a retail store

Though Miracle-Gro Plant Nutrition granules are formulated for vegetable plants, their clean organic matter makes a good choice for your Black-eyed Susans.

Users like that it's very quick and easy to use. Users recommend using it after you start to see sprouts.

View these Plant Nutrition granules on Amazon.

4. Miracle-Gro Bloom Booster

Miracle-Gro does offer an option that is formulated just for flowers. The company states that when it's used correctly, it won't overfeed your flowers and cause burning, which is a good characteristic in fertilizer for Black-eyed Susans.

It's cost-effective and easy to use. You can add one tablespoon to a gallon of water to your watering can or use one packet in the Miracle-Gro disbursement system that attaches to your hose.

See the Bloom Booster from Miracle-Grow on Amazon.

5. Epsoak Epsom Salt

Another organic matter that Black-eyed Susans seem to like is Epson salt. Expert gardeners suggest rotating Epson salt with other fertilizers such as household compost and worm castings.

The magnesium from the salt adds to the richness of the soil and protects against root shock or transplant shock. Avoid pouring solution on leaves and stems.

Click here to see Epson salt on Amazon.

6. Osmocote Smart-Release Plant Food

Farmer filling an Osmocote fertilizer into soil before planting. Osmocote is a controlled-release fertilizer contains a thoughtfully blended mix of nitrogen, phosphorous and potassium.

Avoid overfeeding your Black-eyed Susans by using a product that will feed in a controlled release. Osmocote makes a smart release fertilizer that can feed up to four months after one application.

It's versatile and can be used for both vegetables and flowers. It ensures solid roots and better blooms.

See smart release plant food on Amazon.

7. SUPERthrive The Original Vitamin Solution

Superthrive is another popular option. It's made up of non-toxic ingredients like kelp that will protect the roots and stem of your plant without overfeeding.

It's very concentrated, so a little will take a long way to make it pocket-book-friendly.

See the Original Vitamin Solution on Amazon.

8. FoxFarm Liquid Nutrient Trio

FoxFarm Liquid Nutrient Trio is gentle enough to use throughout the growth cycle.

Its manufacturers state that it is great to use on mature flowers that flower late in the growing season, making it great to use during your Black-eyed Susan's adult days.

9. DR EARTH Flower Girl Bud & Bloom Booster

DR EARTH Flower Girl Bud & Bloom Booster

This bud and bloom booster has a wide range of organic materials, including fish bone meal and alfalfa meal. It also contains high-standard strains of bacteria that improve the soil quality around your plants.

Since it feeds for a few months after application, it can make a good addition to a rotation of fertilizers.

View this bud and bloom booster on Amazon.

10. Organic Kelp Fertilizer By GS Plant Foods

Kelp is the main ingredient in many of the leading plant foods. Get it in its purest form for a gentle addition to your feeding routine.

It can be used during the growth cycle or to lengthen the life of cut flowers; you can spray it a few days before cutting.

See Organic Liquid Kelp on Amazon.

11. Jobe's Organics Organic Fertilizer

Jobe's All Purpose Organic Fertilizer is a granular fertilizer that you can work into the soil around the plant.

It uses biozone technology that increases micro-organism activity and converts the soil into usable nutrients faster.

View this Organic fertilizer on Amazon.

12. Nelson Plant Food

Professional landscapers developed this mineral-rich plant food. Its manufacturers say it remains a favorite among landscapers.

You may see almost immediate results after application, and these granules will keep feeding your Black-eyed Susans for up to four months. You can use it for any flowering plant.

View Nelson Plant Food on Amazon.

13. Scotts Super Bloom Water Soluble Plant Food

Super Bloom from Scotts is high phosphorus, water-soluble plant food, which translates to bigger blooms. It works best on outdoor plants that are in beds or containers.

Some counties and municipalities have laws regarding phosphorus fertilizer in non-agriculture areas, so check your by-laws if you live in a residential zone.

Click here to see Super Bloom on Amazon.

14. Incredible Bulk Vegan Plant Food

Want a fertilizer that no animals have been harmed in the making? There is a vegan option from Incredible Bulk.

It's full of beneficial bacteria that break down the soil and is so clean that it does not leave the deposits behind that other fertilizers might.

It also protects against burns from overfeeding. You can use it both in water or directly in the soil.

See Incredible Bulk Vegan Plant Food on Amazon.

15. Simple Grow Worm Castings

Black-Eyed Susans are strong resilient flowers, but they can still get root and leaf diseases. They also don't do as well in fast-draining sandy soil. Combat both of these issues with worm castings.

Simple Grow says their worm castings will enable the soil to hold more water for more time and protects plant roots from disease. Worm castings enhance microbial activity and can improve the soil in the long run.

When Should You Fertilize Black-Eyed Susans?

Experienced gardeners have different opinions on the best time to fertilize Black-Eyed Susans. The Almanac does not mention fertilizing them in its growing guide.

Most experts agree if you fertilize, use an organic fertilizer early on before the stems push through. Some fertilizers on our list can be used just before cutting to extend the bloom's life.

Consult the manufacturer of your chosen fertilizer for the best time to use it, as different types are beneficial at other times during the flower's lifecycle.

How To Fertilize Black-Eyed Susans

Black Eyed Susan - Flower

Fertilizer mainly comes in granules, liquid, or a dry medium. Water soluble granules or liquid can be applied with a dispersing system attached to your hose or added to a watering can.

Dry granules and other dry mediums are mixed directly into the soil.

To Wrap It Up

Now that you have a list of great fertilizers and when it's best to use them, choose one to get started. Rotate between two or three for best results. You'll have beautiful yellow blooms for years to come.

Made it to the end? You may also be interested in the following:

How And When To Transplant Black-Eyed Susans

Can You Sprinkle Fertilizer On Top Of Soil?