Carnation Fertilizer Tips: Boosting Your Blooms

Carnations are herbaceous perennials from the Dianthus genus that are popular for their beautiful frilly flowers. While carnations are fairly hardy perennials, they do sometimes need a helping hand to produce their best flowers. In this article, I’ll run through everything you need to know about when and how to fertilize carnations for optimal health and maximum blooms each season.

When and How to Fertilize Carnations (Essential Tips)

Which Type of Fertilizer is Best for Carnations?

Carnations are clump-forming perennials with slender grass-like leaves. However, most types of carnations are usually grown for their beautiful flowers rather than their foliage. As such, choose fertilizers that have NPK ratios with lower nitrogen levels. NPK ratios such as 5-10-5 or 5-10-10 work best.

For optimal growth, plant carnations in fertile, well-draining soils that are neutral to slightly alkaline with pH levels between 6.5 and 8.5. However, carnations are hardy plants that don’t need too much fertilizer.

Slow-release fertilizers are best for carnations because they won’t overpower the plant. Liquid fertilizer also works well in small diluted doses.

Good options I’ve tested include FoxFarm Marine Cuisine and Dr. Earth Life Organic Fertilizer

The Role of Fertilizers in Plant Health, Growth, and Development

Bright pink carnation flowers in bloom

Plants get most of their nutrients from the surrounding soil while absorbing water through their roots. However, over time plants deplete the nutrients in the soil. Fertilizers help replenish these nutrients, fueling the development of plants throughout the year.

All plants need four main types of nutrients:

  • Structural macronutrients
  • Primary macronutrients
  • Secondary macronutrients
  • Micronutrients

The three structural macronutrients are carbon (C), hydrogen (H), and oxygen (O). These major nutrients are crucial components in photosynthesis – the process through which plants create glucose. The glucose is then used as fuel to manufacture cellulose, which forms the basis of all plant tissue.

Nitrogen (N), phosphorus (P), and potassium (K) are the three primary macronutrients. Nitrogen fuels foliage development, while phosphorus helps produce flowers. Potassium improves the circulation of water and nutrients.

Secondary macronutrients perform various other functions and include calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), and sulfur (S).

Types of Fertilizers

A person pouring a cap full of liquid fertilizer into a watering can in the garden

Fertilizers are usually either organic or synthetic. Organic fertilizers need to be broken down by organisms within the soil before plants can absorb the nutrients. Synthetic fertilizers work faster and don’t need to be broken down.

All fertilizers have an NPK ratio that explains how much nitrogen, phosphorus, and potassium each dose contains. Different NPK ratios affect plant growth in different ways. High-nitrogen fertilizers encourage more foliage growth, while high-phosphorus fertilizers help produce more flowers.

When to Fertilize Carnation Flowers

Flowering carnations flowers in bloom

Carnations need small doses of fertilizer throughout the growing season. Most carnations bloom from late spring until late summer or early fall. Stop fertilizing carnations during the winter.

If you’re using a slow-release fertilizer, apply a small dose during the spring. Throughout the growing season, apply extra doses every three to four months. If you’re using liquid fertilizer, apply heavily diluted doses once every month or two.

How to Fertilize Carnations

Carnations don’t need much fertilizer and can suffer if over-fertilized. As such, it’s important to fertilize carnations correctly. Here’s a brief guide detailing how to fertilize carnations:

  1. Start fertilizing carnations during the spring. You can use either slow-release fertilizer or liquid fertilizers.
  2. Lightly water the soil around your carnations before applying fertilizer.
  3. If you’re using a slow-release fertilizer, apply a fresh dose once every three or four months.
  4. If you’re using liquid fertilizers, apply a fresh dose every month or two. Always dilute liquid fertilizers according to the instructions on the packet.

Fertilizing Carnations FAQs:

Do Carnations Need Feeding?

Although carnations aren’t heavy feeders, fertilizing them is still beneficial. Feed these fragrant flowers with a slow-release fertilizer once every three or four months. If you want to use liquid fertilizer, apply diluted doses once every month or two throughout the growing season.

Is Miracle-Gro Good For Carnations?

Several Miracle-Gro fertilizers can be good for carnations. Aim to use a slow-release fertilizer once every few months. Alternatively, apply small doses of diluted Miracle-Gro liquid fertilizer once every month or two.

What Compost Do Carnations Like?

Carnations like rich, well-draining soils such as chalky, sandy, or loamy soils. Adding some homemade garden compost adds extra nutrients. Alternatively, give your carnations some organic compost.

Do Carnations Grow Back Every Year?

Most carnations are short-lived herbaceous perennials that live for approximately three or four years when grown from seed. As such, carnations will come back every year. Carnations die back during the winter before regrowing in the following spring. For more, see our in-depth guide to how tall and wide carnations grow under optimal conditions. 

How Do You Keep Carnations Blooming?

Keep your symbolic carnation flowers blooming by making sure that they get approximately four to six hours of full sun. Make sure that your carnation grows in rich, well-draining soil and fertilize it to provide extra nutrients.

How to Fertilize Carnations – Wrapping Up

Carnations need rich, well-draining soils to produce their best flowers but don’t actually need too much fertilizer. If you’re using a slow-release fertilizer, apply doses every three to four months from spring until fall. Dilute liquid fertilizers according to the packet instructions and apply every one or two months. Choose fertilizers with low-nitrogen NPK ratios.


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