5 Best Fertilizers for Hydrangea Plants

Hydrangea plants aren’t heavy feeders but they do better if they’re fertilized. One application of a slow-release fertilizer at the beginning of the growing season or two applications with a liquid fertilizer in spring and summer are enough to keep hydrangeas growing healthy.

You can reach for fertilizers formulated specially for hydrangeas but you can also use all-purpose fertilizers. Below, I review 5 of the best fertilizers for hydrangea plants.

Best Fertilizer for Hydrangeas

Reading through these fertilizer reviews, you’ll probably notice that I’m partial to organic fertilizers, so most of the fertilizers below are great for organic gardening.

– Miracle-Gro Fertilizer for Acid Loving Plants

Specially formulated for acid-loving plants, this plant food from Miracle-Gro will work on hydrangeas, orchids, rhododendrons, camelia, azaleas and other acid loving plants.

It instantly feeds plants stimulating foliage growth and bloom development. The manufacturer recommends using the fertilizer every 7 to 14 days. However, for hydrangeas you may use it less often since it doesn’t require constant fertilizing.

To apply to your hydrangeas, simply dissolve the recommended amount of fertilizer in water and use your watering can to water your hydrangeas.

The effect will be lusher foliage, richer colors and more spectacular blooms.

– Jobe’s Organics Soil Acidifier

Formulated with all-natural sulfur, Jobe’s Organics soil acidifier helps turn alkaline soils acidic. This in turn leads hydrangeas to produce blue colored blooms.

Jobe’s soil acidifier amends alkaline soils to suit the requirements of hydrangeas and improve blooming.

The manufacturer recommends that you test the soil before application to make sure it’s alkaline. You can apply the acidifier when planting your hydrangea, and then reapply it 2-3 times a year to maintain soil acidity.

If you’re eager to turn pink hydrangea blooms blue, give this soil acidifier a try.

– Espoma HT18 Holly Tone

Another organic hydrangea fertilizer that I love is the Espoma Holly Tone. It’s a 4-3-4 formulation fertilizer that’s derived from feather meal, bone meal, alfalfa meal, greensand, sulfate of potash, poultry manure, calcium, magnesium, and 6,000,000 colony forming units (CFU) per gram of beneficial microbes.

Besides hydrangeas, this fertilizer also helps other plants that thrive in an acidic environment including azaleas and rhododendrons. Blueberries and strawberries also benefit from Espoma’s Holly Tone.

You can either work it into the soil or apply on the surface of the soil then water your hydrangeas.

– Down to Earth All Natural Acid Mix Fertilizer 4-3-6

This special blend for acid loving plants contains cottonseed meal, langbeinite, fish bone meal, rock phosphate, humates, and kelp meal.

The manufacturer recommends two applications — once in spring at the beginning of the growing season and once when blooms appear.

It’s suitable for use in organic gardening, which is especially important because the fertilizer can be used with success on other acid loving plants and fruits including blueberries and raspberries.

Down to Earth All-Natural Acid Mix promotes vigorous plant growth, colorful blooms and fruit formation.

– Dr. Earth Organic Acid Fertilizer

A 4-5-4 formulation fertilizer that I also recommend comes from Dr Earth and it’s an organic, hand-crafted blend enriched with cottonseed meal, Alaskan fish bone meal, valley-grown alfalfa meal, kelp meal, natural potassium sulfate, and concentrated seaweed extract.

Besides these, the acid fertilizer from Dr Earth also contains beneficial soil microbes and mycorrhizae. Together, these components provide continuous feed to your hydrangeas and contribute to higher nutrient availability and increased plant performance.

As dry fertilizer, use it in raised beds during transplanting or as a mid-season feed for a nutritional boot. It can be used for hollies, azaleas, camelias, blueberries, evergreens, shade plants and other plants that need a more acidic growing environment.

How and When to Fertilize Hydrangeas?

At the very minimum, hydrangeas can be fertilized at the beginning of the growing season and then once again in mid-summer. The frequency can vary depending on the type of fertilizer you’re using.

A slow-release fertilizer may only need one application at the beginning of the growing season. Instant liquid fertilizer may require 2-3 repeat applications, and soil acidifiers can also require repeat applications throughout the growing season.

If you’re using a slow-release fertilizer or other dry fertilizer, you can work the fertilizer into the soil or choose a simple surface application, then water it in.

Water soluble fertilizers are usually diluted in water in a watering can and they can be applied to the soil directly from the watering can.

Whichever method you use, make sure to carefully follow the dosage and dilution recommendations to prevent fertilizer burn. It’s better to use less of a fertilizer or to create a weaker solution than to use too much of it.

Are Coffee Grounds Good for Hydrangeas?

If you’re a coffee drinker, don’t throw coffee grounds away. Use them as a soil amendment for your hydrangeas. Just like soil acidifiers, coffee grounds can also reduce the pH of soil and turn pink blooming hydrangeas into blue blooming ones.

Remember that used coffee grounds are not as acidic since hot water will reduce some of the initial acidity, so don’t expect your hydrangea blooms to turn acidic after just one application.

Besides this bloom color changing effect, coffee grounds can also improve drainage, especially when used in a composted form and improve the overall quality of the soil.

You can either work coffee grounds into the soil or apply them over the soil. I prefer to apply coffee grounds in a composted form and apply the compost over the soil.

Is Epsom Salt Good for Hydrangeas?

Hydrangeas can benefit from epsom salt added to their soil. Epsom salt is just another name for magnesium sulfate and most soils usually contain magnesium sulfate but not in the quantities needed for some plants.

Contrary to some beliefs, epsom salt does not turn hydrangea blooms blue. But it does improve roots systems, stem strength, and enhances the color of leaves and blooms.

Wrapping Up

Supplementing naturally available nutrients in the soil will have a beneficial impact in the growing stages of hydrangeas when the plant requires excess nutrients to stimulate root growth, stem development, leaf formation and blooming.

The fertilizers I recommended in this article are formulated to meet the nutritional requirements of hydrangeas. Because most of them are an all-natural blend, they’re also suitable for organic gardening.