Try these easy-to-make homemade fertilizers for coleus and boost your plant’s foliage, color, and overall health!
Coleus is loved for its colorful leaves and fast growth, but to keep it looking full and fresh, you have to give it sufficient light and the right kind of feed.
Instead of relying only on plant food from the market, you can try one of these homemade fertilizers that work just as well (sometimes better) for coleus.
Best Homemade Fertilizers For Coleus
1. Use Compost Tea
Compost tea is often the gardening favorite, and for coleus, it’s like serving a leafy-green latte. It’s packed with soluble nutrients, beneficial microbes, and trace minerals that will feed your plant and also improve soil health over time.
Unlike chemical fertilizers that can be too harsh, compost tea gives coleus a gentle and balanced boost, without stressing its tender roots.
Steep a few shovels of well-aged compost in a bucket of water for 2–3 days and stir occasionally. After that, strain it, and you’ve got your liquid plant food.
- When to Feed: You can apply every 2–4 weeks during spring and summer, when coleus grows fast and needs extra nutrition.
- How Much to Feed: For small pots, give your plant about 1 cup, and for large containers or garden plants, up to 4 cups is ideal.
- Why It Works: Compost tea provides gentle nitrogen for leaf production and beneficial microbes that improve nutrient uptake. This helps coleus maintain rich colors without chemical overload.
Pro Tip: For extra strength, add a teaspoon of molasses to the brew—it feeds the microbes and makes the tea more effective.
2. Banana Peel Fertilizer
Don’t throw banana peels into the bin. They’re loaded with potassium, calcium, and phosphorus, all of which are crucial for leaf color and stem strength in coleus. Potassium, in particular, helps intensify leaf patterns and makes plants more resistant to heat stress or irregular watering.
In fact, banana peels are about 42% potassium by dry weight, making them one of the richest natural sources available. This high potassium content directly fuels vibrant leaf variegation and encourages upright growth.
You can blend banana peels with water into a slurry and pour it around the base of your coleus. If you want a longer-lasting effect, dry the peels in the sun, grind them, and sprinkle the powder into the soil. You can also use dried banana peel powder with a little coffee ground for a quick DIY foliage booster.
- When to Feed: Use it once every 4-6 weeks, during peak summer, when coleus color tends to fade if the plant is underfed.
- How Much to Feed: You can use one blended peel per medium plant, or 1–2 tablespoons of dried powder mixed into the soil.
- Why It Works: Potassium boosts pigmentation, while calcium strengthens cell walls, which help coleus maintain its bold leaf structure and vibrant hues.
Pro Tip: Freeze banana peels before blending for a smoother consistency and stronger nutrient release.
3. Apply Coffee Grounds
Coffee wakes you up, and it can perk up coleus, too! Grounds are one of the easiest kitchen fertilizers, rich in slow-release nitrogen that fuels leafy growth. Since coleus is all about bold foliage, coffee grounds are a perfect fit. They also improve soil texture by adding organic matter and helping with drainage.
Sprinkle dried grounds on the soil or mix them lightly into the potting mix. Avoid dumping them wet and clumpy, as that can block airflow and water movement.
- When to Feed: Once or twice in a growing season is enough for slow-release nourishment.
- How Much to Feed: Sprinkle a thin, half-inch layer and gently mix it into the topsoil.
- Why It Works: Nitrogen fuels leaf growth, while the organic matter helps coleus roots stay moist but not soggy—crucial for bushy, balanced plants.
4. Epsom Salt Solution
Epsom salt (magnesium sulfate) is one of the simplest ways to bring out brighter coleus leaves. Magnesium is essential for chlorophyll production, which means greener, more colorful foliage. Without it, leaves can look pale or dull.
All you need to do is dissolve a tablespoon of Epsom salt in a gallon (about 4 liters) of water and apply it as a soil drench. For an even quicker fix, you can also use it as a foliar spray directly on the leaves.
- When to Feed: Apply it once every 4–6 weeks during active growing months.
- How Much to Feed: One gallon of diluted mix per 2–3 plants, poured evenly at the base, will be enough.
- Why It Works: Magnesium and sulfur enhance photosynthesis, boost color intensity, and strengthen plant tissue, which keeps coleus leaves bold and resilient.
Pro Tip: Pair an Epsom salt spray with all-day long indirect sunlight exposure, as brighter conditions plus extra magnesium will add to the foliage vibrancy.
5. Use Fish Tank Water
If you keep an aquarium, don’t throw away that water during cleanups because it can be the best liquid fertilizer for your coleus.
Fish waste breaks down into nitrates, phosphates, and potassium, and all of these are essential for strong leaf growth and healthy roots. Best of all, it’s free and eco-friendly.
Aquarium water is naturally rich in nitrogen (from fish waste), which fuels lush, green foliage, and contains trace amounts of magnesium and calcium that strengthen cell walls. Together, these nutrients keep coleus leaves vibrant and prevent stunted growth.
Replace a watering session with leftover tank water and watch your coleus respond. Unlike some homemade fertilizers, fish tank water is mild, so you won’t risk overfeeding or burning your plants.
- When to Feed: Every 2 weeks during water changes, or once a month if that’s more practical.
- How Much to Feed: Water the plant as you usually would, just dilute it in the ratio of 1:1 with regular water.
- Why It Works: Fish waste provides balanced nutrition while beneficial bacteria in the water improve soil health. This gives coleus both instant and long-term growth support.
6. Crushed Eggshells
Eggshells release calcium slowly, which strengthens coleus cell walls and prevents weak, floppy growth. Calcium also helps new shoots develop properly and keeps leaves from tip burn.
You just have to crush or grind eggshells into fine particles before mixing them into the soil. It will ensure faster breakdown and quicker nutrient release. In addition to being the best fertilizers, they will help you deter slugs and snails when sprinkled around outdoor coleus beds.
- When to Feed: You can feed it during repotting or as a top dressing every 3 months.
- How Much to Feed: 2–3 crushed shells per plant are enough when mixed into the topsoil.
- Why It Works: Eggshells improve soil structure, add calcium for stronger foliage, and provide a slow-release nutrient source without risk of overfeeding.
Pro Tip: Bake shells at low heat before crushing. This kills bacteria and makes them brittle for easier grinding.
Try adding them to your routine and watch your plants turn into stunning foliage showpieces that will turn heads.
