Composting is a fantastic way to recycle your garden and kitchen waste, creating nutrient-rich material for your plants. You’ve put in the effort, turning your scraps into a hot, crumbly mulch – but what next? While spreading it over the garden as mulch is always a great option, there’s another exciting way to make even better use of your compost. With a few additional ingredients and simple techniques, you can transform it into custom potting mixes—perfect for sowing seeds, potting plants, filling containers or even for indoor houseplants.
This guide will show you how to get started, what you’ll need, and offer recipe ideas to create high-quality, homemade potting mix. Let’s get mixing!
Why Turn Your Compost into Potting Mix?
Creating your own potting mix at home has some major benefits.
- Cost savings: Skip the expensive store-bought bags and cut your gardening costs significantly.
- Custom blends: Tailor your mix to suit specific plant needs—seedlings, container plants or even houseplants.
- Sustainability: Reuse your waste and reduce the demand for commercial compost production.
Homemade potting soil is not just practical; it gives you complete control over your garden’s foundation.
What You’ll Need to Get Started
To turn your compost into versatile potting mixes, you’ll need a few extra ingredients alongside your compost. These additions help balance drainage, texture and nutrients for different plants.
Essentials for Your Mix:
- Sieved compost: Start by sifting your compost through a garden riddle or fine mesh to remove large, uncomposted chunks. This creates a smooth, even base for your potting mixes.
- Sand or Grit: Improves drainage and aeration, essential for many types of plants. Use horticultural sand or grit to avoid salts or impurities found in builders’ sand.
- Coir or Leaf Mould: Acts as a moisture retainer, helping to balance the mix. Coir is made from coconut fibre, while leaf mould is an excellent alternative if you have access to decomposed leaves in your garden.
- Garden Soil: Adds structure and nutrients, making the mix perfect for heavier planting requirements like shrubs or vegetables. Be sure to sterilise your garden soil beforehand to eliminate pests and diseases.
- Perlite or Vermiculite: Lightweight materials that help with drainage and moisture retention, especially for seedlings and houseplant mixes.
Optional Ingredients:
- Wood Ash: Provides potassium, which is ideal for fruiting plants. Use sparingly.
- Bone Meal or Fertiliser: To add nutrients that may be lacking, especially when growing plants in containers.
- Lime: If your compost tends to be acidic, lime can help balance the pH for specific plant types.
Proportions of these ingredients will vary depending on the purpose of your mix—read on for some easy recipes you can follow.
Mix Recipes for Every Need
1. Seed-Sowing Potting Mix
Young seeds are delicate and need a light, airy mix to thrive. This mix ensures proper drainage while being nutrient-rich enough to support germination.
- 1 part sieved compost
- 1 part coir or leaf mould
- 1 part fine sand or perlite
Perfect for: Sowing vegetable or flower seeds in trays or pots.
2. General-purpose Potting Mix
A versatile mix for potting on young plants or filling containers for annuals and perennials.
- 2 parts sieved compost
- 1 part garden soil
- 1 part grit or sand
Perfect for: Repotting plants and filling outdoor containers.
3. Container Plant Mix
Plants grown in containers need extra nutrients and good drainage. This recipe provides a rich base and helps plants stay hydrated.
- 2 parts sieved compost
- 1 part perlite or vermiculite
- 1 part coir
- A small handful of organic fertiliser (e.g., bone meal)
Perfect for: Flowers, vegetables, and herbs in pots.
4. Houseplant Mix
Houseplants require specific care, and this mix helps balance moisture and drainage to keep them happy indoors.
- 2 parts sieved compost
- 1 part coir or leaf mould
- 1 part perlite or vermiculite
- Optional: Add a small amount of activated charcoal to prevent odours in indoor pots.
Perfect for: Fiddle-leaf figs, succulents, pothos, and other houseplants.
5. Acid-Loving Plant Mix
Some plants, like azaleas and blueberries, prefer acidic conditions. Modify the general-purpose mix by adding ericaceous compost or sulphate of ammonia.
- 2 parts sieved compost
- 1 part garden soil
- 1 part grit or sand
- A small handful of sulphate of ammonia or ericaceous compost
Perfect for: Acid-loving shrubs or berry plants in pots.
Final Tips for Success
- Sterilisation: If using garden soil, always sterilise it by baking it in the oven at 180°C for 30 minutes. This eliminates pests, weed seeds and diseases.
- Customise for Plants: Don’t be afraid to tweak these recipes based on your plants’ needs. Add more sand for succulents or more compost for vegetables.
- Store Carefully: Keep any unused potting mix in a sealed container to prevent it from drying out or being contaminated.
By experimenting with your mixes, you’ll learn what works best for your garden and indoor plants.
Bring Your Garden to Life—Naturally
Turning your homemade compost into potting mix isn’t just a sustainable initiative. It’s a creative way to refine your gardening skills while saving money and resources. Whether you’re sowing seeds, repotting plants or nourishing houseplants, these natural mixes make it easy to grow healthier, happier plants.
Why not give it a try today? Your plants—and your garden budget—will thank you!
Further reading: Compost Wormery, What is Composting, Homemade Garden Fertilisers