How to Use Leftover Coffee Grounds to Fertilize Houseplants

How to Use Leftover Coffee Grounds to Fertilize Houseplants

How to Use Leftover Coffee Grounds to Fertilize Houseplants

Using leftover coffee grounds to fertilize houseplants is an easy and environmentally-friendly way to reuse kitchen scraps. Here’s a complete guide on how to use spent coffee grounds in your indoor garden.

Why Use Coffee Grounds as Plant Fertilizer

Coffee grounds contain essential nutrients that provide multiple benefits for houseplants. Here are some key reasons to use them:

  • Rich in nitrogen – Coffee grounds are high in nitrogen, one of the macro nutrients plants need to thrive. Nitrogen promotes healthy green growth and strong stems.

  • Provide phosphorus and potassium – In addition to nitrogen, coffee grounds contain phosphorus and potassium, two other vital nutrients for plants.

  • Acidify soil – The acids in coffee grounds help lower the pH level of soil, which many indoor plants prefer. This can help them absorb nutrients more efficiently.

  • Improve soil structure – As a natural material, coffee grounds can aerate and add organic matter to potting soil when mixed in. This leads to better water retention and drainage.

  • Insect deterrent – The caffeine in coffee grounds may help repel certain insects and pests from the soil.

  • Free fertilizer – Rather than letting grounds go to waste, reusing them eliminates the need to buy chemical plant foods. It’s economical and eco-friendly.

Which Houseplants Like Coffee Grounds?

Most houseplants can benefit from some additional nitrogen in their potting mix. Here are some indoor plants that do particularly well with coffee fertilizer:

  • Succulents – Coffee energizes slow-growing succulents like jade plants, aloe vera, and Christmas cactus. The acidity also suits them.

  • Orchids – Orchids thrive with the acidity that grounds provide. The nitrogen also encourages blooms.

  • Ferns – Coffee’s nitrogen boosts the lush green foliage of ferns. Boston ferns, bird’s nest ferns and staghorn ferns are especially responsive.

  • Palms – Nutrient-demanding palms like areca palms, bamboo palms and parlour palms love coffee fertilizer.

  • Ficus – The familiar fiddle leaf fig and other ficus species produce vibrant leaves with coffee’s nitrogen.

  • Crotons – Coffee stimulates brilliant coloration in the leaves of croton houseplants.

  • Bromeliads – For bromeliads like air plants and pineapple plants, the acidity is ideal.

How to Prepare and Apply Coffee Grounds

Follow these steps for using coffee grounds to feed your houseplants:

Gather Used Grounds

  • Collect wet, used grounds immediately after brewing coffee. Letting them dry out reduces their fertilizing value.

  • Tip: Put a small bucket or container beside your coffeemaker to directly catch drips.

Combine with Potting Mix

  • Blend some grounds into the potting soil as you re-pot plants. This provides extended fertilization.

  • Use no more than 20% grounds to 80% potting mix.

Top dress pots

  • Sprinkle dried grounds lightly over the surface of potted plant soil every 2-4 weeks.

  • Try 1-2 tablespoons per 6 inch pot. Water well after applying.

Make compost tea

  • Steep grounds in water overnight, strain and use the “tea” to water plants. This quickly provides nutrients.

  • Use a ratio of 1/4 cup grounds per gallon of water. Dilute if needed.

Mulch soil with grounds

  • Spread used coffee grounds as mulch in the top layer of potting soil. This retains moisture and suppresses weeds.

  • Lay down 1/2 inch deep maximum to prevent mould growth.

Tips for Using Coffee Grounds on Plants

Follow these best practices when repurposing your leftover coffee grounds for houseplants:

  • Use grounds in moderation – Too much can overload plants with nitrogen.

  • Avoid letting grounds dry out completely before use. Dried grounds lose nitrogen content over time.

  • Mix grounds into soil, don’t just layer them on top. This prevents mould growth.

  • Alternate coffee grounds with other fertilizers. Don’t rely solely on one nutrient source.

  • Monitor plants carefully and adjust amounts as needed. Reduce if you notice burned leaf tips.

  • Rinse foliage after fertilizing to avoid any residual acidity burning leaves.

  • Coffee can lower soil pH significantly. Check pH yearly and add lime if needed.

With a little routine care, used coffee grounds can be a safe, sustainable plant food source for vibrant and healthy houseplants. Give your indoor garden a java boost!