How Do I Fertilize Blueberries with Black Gold Fertilizer?

“I would like to fertilize some small blueberry plants I bought this year. I have your BLACK GOLD RHODODENDRON, AZALEA & EVERGREEN FERTILIZER, and I have some questions about its use because I don’t understand the instructions. It says “new plantings, 500ml per 1.5 m squared.  Or 1.5 cups for every inch of diameter of the trunk.  My plants are nowhere near 1-inch in diameter.  I have a round pot, 15 inches diameter, and I have another plant, in a 14 X 20” rectangle. Also, doesn’t the depth matter as well when determining how much fertilizer to put in? Here are three more questions.

  1. How do I know how much fertilizer to put in?
  2. It says  “measure 6 inches above the soil line”. What is the soil line? Then you say “the drip line”. What is the drip line?
  3. The instructions say to mix the fertilizer in with the soil.  How do you do that once the plant is already potted?”

Question from JM of Toronto, Canada

Answer: We are happy to answer your question about how to apply Black Gold Rhododendron, Azalea & Evergreen Fertilizer. Here are the answers to your three primary questions.

  1. You will need to extrapolate from the guide suggestion: “Add 1.5 cups for every inch of diameter of the trunk.” For example, if the stem of your blueberry is approximately 1/2 inch in diameter, then work in 3/4 cup (175 mL) of fertilizer around the root zone of your blueberry. If it is smaller, extrapolate to add less.
  2. The soil line is the soil layer that covers the roots, while the drip line is the diameter area of the plant crown. Please see the schematic below.
  3. If you are adding fertilizer to a pot, then gently work it into the soil around the roots from the top. You do not need to work it in deeply. The fertilizer will make its way down to feed your plants every time you water.

We hope that this information helps.

Happy gardening,

Jessie Keith


What Are The Best Potting Soils for Dahlias, Lilies, and Begonias?


“What kind of potting soil should I use for Dahlias, Asiatic and oriental lilies, and begonias?” Question from Luciana of Portland, Oregon

Answer: Each flowering plant has some distinct needs when it comes to soil moisture, pH, and quality. The right kinds of fertilizers also help these flowers bloom at their best.

Soil and Fertilizer for Dahlias

Potted Dahlias need porous soil that drains well, holds moderate moisture and has a slightly acid to neutral pH (6.2 to 7). I recommend our Black Gold® All Purpose Potting Mix or OMRI Listed Black Gold® Natural & Organic Cocoblend Potting Mix, which is approved for organic gardening. Both potting soils have all the right characteristics. When picking a fitting fertilizer, choose one formulated for blooming plants. Proven Winners Premium Continuous Release Fertilizer is a good choice. Adding Proven Winners Premium Water Soluble Plant Food as directed will also help boost flowering through summer.

Soil and Fertilizer for Asiatic and Oriental Lilies

Lilies of all types grow best in soils that are well-drained and rich in organic matter. The ideal pH should be a little more acidic (5.5 to 6.5), but neutral soils are also tolerated. Once again, I recommend our Black Gold® All Purpose Potting Mix in addition to another of our OMRI Listed mixes, Black Gold Natural & Organic Ultra Coir, which is rich in organics but drains well. Here, it is best to choose a fertilizer specially formulated for summer bulbs. These tend to be balanced fertilizers with added bonemeal, and there are many fine choices on the market.

Soil and Fertilizer for Begonias

Fast-draining soils that are light and fertile are preferred by begonias. Their tubers or fibrous roots are prone to rot, so soils that hold onto water too well can be detrimental. Once again, a slightly acid pH (5.5 – 6.5) is needed. Black Gold® Natural & Organic Potting Mix is a good soil choice. Adding a little extra Black Gold Perlite for added drainage is also recommended. Proven Winners Premium Continuous Release Fertilizer helps boost flowering and performance in begonias. The occasional addition of Proven Winners Premium Water Soluble Plant Food will also help boost flowering.

Have a great gardening season!

Jessie Keith

Black Gold Horticulturist

Can I Use Black Gold Fertilizer On My House Plants?

“Can I use black gold fertilizer on my houseplants? ( 5 5 5 ) Any plants I should feed like ferns, orchids, African violets, etc?” Question from Gayle of New York

Answer: Black Gold Fertilizers are only available in Canada. You can certainly use our granular, Black Gold All-Purpose Fertilizer on house plants if you can find it in the states. Otherwise, we recommend that you try Proven Winners Premium Continuous-Release Plant Food and Proven Winners Premium Water Soluble Plant Food as an all-purpose fertilizer for feeding house plants. They are particularly recommended for flowering house plants. Our parent company, Sun Gro Horticulture, makes these products, so we can vouch for its quality and performance. Follow the product directions for application rates. From there, here are further resources for house plant care.




Happy gardening!

Jessie Keith

Black Gold Horticulturist

Do Blueberries and Strawberries Need to be Fertilized?

Do Blueberries and Strawberries Need to be Fertilized?

“Do blueberries and strawberries need to be fertilized?” Question from Melanie of Holton, Michigan

Answer: Absolutely! Fertilization will encourage better growth, flowering, and fruit set. Each berry type has different needs when it comes to fertilizer.

Fertilizing Blueberries

Blueberries grow best in more acid soils (pH between 4.5 and 5.5) and require a specialty fertilizer formulated for acid-loving plants and/or berries. I generally fertilize in spring with a continuous-release fertilizer, but how you fertilize will depend on the product you choose. Follow the manufacturer’s application recommendations. There are many types of blueberry shrubs. To learn more, watch our video all about choosing and growing blueberries.

Fertilizing Strawberries

Strawberries like soils with a more neutral pH, and are less fussy. To encourage berry production, choose a specialty fertilizer formulated for strawberries or berries. There are many on the market. If your strawberries are June-bearing then I recommend fertilizing them in early spring and again later in the season, depending on what fertilizer you choose. If your strawberries are everbearing, then I would fertilize them with a continuous-release fertilizer in spring as well as a water-soluble fertilizer that will encourage them to produce berries through summer. For more information about growing strawberries watch this video.

I hope that this information helps!

happy berry growing,

Jessie Keith

Black Gold Horticulturist

How Do I Organically Feed My Vegetable Garden Soil for Fall?

How Do I Organically Feed My Vegetable Garden Soil for Fall?

“I’m getting ready to prep my raised beds for the fall crop.  What is best to amend the soil with since I do not use chemical fertilizers?” Question from Randal of Chiply, Florida.

Answer: There are lots of things that you can do to feed your soil for fall and winter crops. Here are some of easy options.

Feed Your Soil

Your garden is as good as its soil. For success, liberally feed it with organic matter, such as Black Gold Earthworm Castings, Canadian Sphagnum Peat Moss, and Garden Compost Blend, especially if your soil is rich in clay or sandy. Add at least 3 inches of the amendment to the soil surface, and till it to a depth of at least 8 inches. Tilling in amendments will increase water-holding capacity and aeration for better root growth. Use the amendment application formula below to determine the amount you will need.

Amendment Application Formula

([area to cover] ft2 x [depth in inches desired] x 0.0031 = ___ yd3).

Example: If you wanted to cover a 20 square foot area with 2 inches of compost, the result would be: 20 ft2 x 2 inches of compost x 0.0031 = 2.48 yd3.

(Click here for a full overview of how to prep a new vegetable garden from start to finish.)

Choose the Right Organic Fertilizer

Vegetables perform better with regular fertilization, especially heavy feeders like tomatoes. In fact, most veggies will deplete the soil of nutrients over time, so replenishment is necessary. There are many organic vegetable fertilizers on the market. Alfalfa, blood, bone, feather, fish, kelp, and shrimp meals are all common natural components of non-chemical fertilizers. Earthworm castings are also a good source of nitrogen and beneficial microbes. Adding mycorrhizae to the soil is also useful because it helps plants take up water and nutrients better. Black Gold Natural & Organic Ultra Coir is another of our organic-rich amendments that also contains our proprietary blend of endomycorrhizae. We recommend that you research top-rated organic fertilizers to find the best for your needs.

Rotate Your Crops with Legumes

Vegetables, especially tomatoes, should be rotated on a three-year cycle–tomato one year and other vegetables the next two years. Legumes, like beans and peas, are excellent rotation crops because they naturally fortify soils with nitrogen. For more rotation tips, I encourage you to read Spring to Fall Vegetable Rotation: Planting for Non-stop Garden Produce. It will provide all of the information you need to effectively rotate your crops, whether container- or garden-grown.

I hope that all of this information helps! We have many more articles about gardening in Florida, click here to view them.

Happy fall vegetable gardening,

Jessie Keith

Black Gold Horticulturist

How Long Does Compost Feed Plants?

How Long Does Compost Feed Plants?

“How long does compost feed plants? And if you have compost in the ground, do the plants still need fertilizer? I use plant-based food scraps, grass clippings, and shredded paper for trench composting. It breaks down very quickly here in the Sonoran Desert.” Question from Jacqueline of Casa Grande, Arizona

Answer: The value of compost to plants depends on how long it takes to break down. Compost adds needed structure, water-holding capacity, aeration, and microorganisms to garden soil. Overall, it feeds and enriches soil, but its nutrient profile depends on what you feed into your compost pile. For example, if you add lots of eggshells your compost will have higher calcium content. With that said, you should also add balanced fertilizer to your garden beds–especially where soils are nutrient-poor. As your compost breaks down and disappears, it is no longer working its magic, so keep it replenished. And, if you run out you can always supplement further with products that are high in organic matter, such as Black Gold Garden Compost Blend, Just Coir, or Canadian Sphagnum Peat Moss.

Happy gardening!

Jessie Keith

Black Gold Horticulturist

Is Comfrey a Good Natural Fertilizer?

“Have you heard about comfrey as being an organic fertilizer for gardens, and do you have any additional information on it?” Question from Sylvia of Belle Plaine, Minnesota

Answer: The claim is that the old-fashioned herb comfrey (Symphytum officinale) is a “dynamic accumulator,” or a plant that absorbs and retains higher amounts (10 x or more) of essential macronutrients, such as nitrogen, phosphorus, and potassium, as well as micronutrients. Plants that absorb and retain lots of nutrients make great natural fertilizers that boost compost and can be used as green manure crops or to make fertilizer teas.

Some research has been done on the subject, and despite the claims, comfrey does not fall into the category of a dynamic accumulator. It only has a Nitrogen, Phosphorus, and Potassium (NPK) ratio of between 3-1-5 and 1.8-0.5-5, while other common plant products, such as corn gluten meal (~9-1-0) and soybean meal (~7-1-2) are far more nutritious but still not considered dynamic accumulators. So, comfrey offers some fertility but is not an extraordinary natural fertilizer.

Dynamic Accumulators for Natural Fertilization

But, there are several true dynamic accumulators worth considering for natural garden fertility. Some of the best are common weeds, such as stinging nettle (Urtica dioica) with an estimated NPK of 12.5-8.5-16, lamb’s quarters (Chenopodium album), which is reported to accumulate very high amounts of Nitrogen, Potassium, Phosphorus, Calcium and Manganese, horsetail (Equisetum arvense), which accumulates high amounts of Potassium, Phosphorus, and tons of Silicon, amaranthus (Amaranthus spp.), which accumulates very high amounts of Calcium, and finally the humble dandelion, a high accumulator of Iron. Some of the annual weeds, such as amaranth and lamb’s quarters, can be planted as green manure crops and tilled under before they set seed.

Finally, don’t forget the power of garden legumes, such as beans, peas, alfalfa, and lupines, for naturally adding nitrogen to the soil. These are some of the finest plants for providing natural fertility to your garden soil. (Click here to read an article about nitrogen-fixing plants.)

I hope that this answer helps!

Happy gardening,

Jessie Keith

Black Gold horticulturist


Is Bat Guano Good for Flower Beds?

“I have a large amount of bat dung in our barn and have heard that it is an excellent fertilizer for flowers. Is that true?” Question from Catherine of White Cloud, Michigan

Answer: Bat guano makes an excellent plant fertilizer once it has been composted. Fresh bat guano is rich in nutrients, particularly nitrogen, but it needs to be broken down and mellowed before use. This is the same for any manure (cow, horse, etc.) that you may want to add to the garden.

To compost it, pile up the guano, layering in grass clippings, dry leaves, vegetable waste, and/or straw as you go. The higher the pile, the better. Do this in a composter, if you have one, or in a convenient spot outside of your barn. Once the pile is complete, moisten it, and allow it to naturally compost/decompose for a couple of months. In this time, the pile will heat up in the center. Turn it with a spade or garden fork every two weeks and keep it moist to ensure that the whole pile gets composted. Once it is ready to use, it will be cool in the center and very crumbly and soil-like.

To reduce its high nutritional punch, consider cutting your composted guano with standard compost, such as Black Gold Garden Compost Blend, before use. Because guano is high in nitrogen, which encourages foliage growth rather than flower development, mix in a granular fertilizer formulated for flowering plants before adding it to your beds.

Keep gathering and using your guano! It’s good stuff for the garden.

Happy gardening,

Jessie Keith

Black Gold Horticulturist

Should I Fertilize My Vegetable Garden in Winter?

“What is the best nutrient to use when preparing for a vegetable garden in the winter months?” Question from Denise of Clemmons, North Carolina

Answer: Vegetable fertilization regimes always depend on the plants you are growing. Winter crops for cold frames or hoop gardens tend to consist of cold-tolerant greens, herbs, and root crops. Nitrogen is the best fertilizer for growing leafy crops, while phosphorus and potassium support strong root growth.

If you do not plan to plant winter vegetables in your garden, wait until spring to add an all-purpose granular fertilizer for vegetables. Or you can also consider planting a nutritious winter cover crop, like winter wheat or buckwheat. This article lists a few good cover crops that naturally feed the soil.

There is one more point to consider, your choice of organic versus inorganic fertilizers. Organic fertilizers generally contain nutrients that are converted into accessible forms by soil microbes before plants can use them. These microbes are less active in the cold, to the nutrients will be less available to plants, so inorganic fertilizers will make nutrients more readily available to winter crops.

Happy Gardening!

Jessie Keith

Black Gold Horticulturist

What is the Best Fertilizer for Herbs?

“Is there a specific product that is ideal to use for feeding my herbs (potted, indoors)…?” Question from Stephanie of Elizabeth, Colorado

Answer: When it comes to feeding leafy herbs, it’s all about the nitrogen. This is the macro-nutrient that encourages strong leaf development. Choose a leafy green vegetable fertilizer that’s high in nitrogen. I tend to prefer sprinkle-and-forget, slow-release fertilizers that are OMRI Listed for organic gardening. They are easy to apply and ensure plants are getting fertilized at each watering.

Happy herb gardening!

Jessie Keith

Black Gold Horticulturist