20 December 2022, by Benedict Vanheems
The rising cost of potting soil has many gardeners feeling the pinch, especially when it comes to filling large containers or raised beds. But don’t worry – there are several ways to make your potting mix go further without breaking the bank. Here are five easy, cost-effective strategies to help you save on soil and compost.
1. Fill Pots for Less
Potting mix can run out quickly, especially during peak growing season. But do you really need to fill all your containers with expensive potting mix? For shallow-rooted plants like lettuce, radishes, and strawberries, you only need around 6 inches (15 cm) of soil. Instead of filling the entire container with potting mix, consider using free materials like chopped twigs, straw, or old leaves to bulk up the base.
For heavier feeders such as cucumbers or squash, consider filling part of the container with nutrient-rich kitchen scraps or fresh leaves from plants like comfrey to provide extra nutrients. This method reduces the amount of costly potting mix you need.
2. Reusing Potting Soil
Old potting mix doesn’t have to go to waste. You can reuse it by rejuvenating it for another round of planting. Start by drying out the mix and removing any plant debris and roots. Once dry, add fresh potting mix and some organic fertilizer like blood, fish, and bone or a vegan alternative to refresh its nutrient content.
However, if the old mix came from diseased plants, avoid reusing it to prevent transferring diseases. As a rule of thumb, you can repurpose soil used for flowers to grow vegetables, or vice versa.
3. Stretch Potting Mix with Compost or Sand
To make your potting mix go further, mix it with homemade compost or sand, depending on your plants’ needs. For heavy feeders like tomatoes and cabbages, rich, dark compost will provide extra nutrients. On the other hand, for root crops like carrots, mix potting soil with sand to create a lighter, well-draining medium.
You can also mix equal parts of potting mix and sand to improve drainage or use sieved compost to enrich your growing medium. If you’re feeling adventurous, making your own potting mix from scratch is an affordable alternative.
4. Create Compost Pits
Instead of buying compost, you can create your own by digging compost pits in your garden. Add kitchen scraps to a pit or trench, then cover them with soil. The scraps will decompose over the winter, enriching the soil for the upcoming growing season. This method is especially effective for those with limited space or resources for composting.
5. Build Free Raised Beds with the Lasagna Method
The lasagna method is a fantastic way to build raised beds for free. Layer organic materials like cardboard, straw, grass clippings, and spent plants to form your growing medium. Start with a layer of cardboard to suppress weeds, then alternate between carbon-rich “brown” materials (like straw) and nitrogen-rich “green” materials (like grass clippings). Aim for a bed at least 18 inches (45 cm) high.
As the organic matter breaks down, it will create nutrient-rich soil. This method is particularly effective in the fall or early winter, as freezing and thawing help decompose the materials. If the bed hasn’t broken down fully by spring, top it off with a little compost and start planting.
By using these strategies, you can reduce your reliance on expensive potting soil and compost while creating healthier, more sustainable growing environments for your plants. Happy gardening!