How to Refresh Old Potting Soil

Container gardens and indoor plants require repotting on a yearly basis in order to keep plants looking their best. Instead of purchasing new soil, try refreshing the existing potting soil. It is an easy DIY project that will save you tons of cash over the years.

Use Compost

If the potting soil is not leaching salts, you can refresh your potting soil easily by mixing it with equal amounts of compost. Remove the plant from its pot, gently shake off excess soil from the roots, and add the potting soil to a large tub or trash can. Mix in equal amounts of compost and moisten. Repot the plant into a slightly larger planting container with the potting soil/compost mix.

If you do not have a compost pile, it is never too late to start one. Just mix equal amounts of dry items (dry leaves, twigs, sawdust and shredded paper) with wet items (green plant material, vegetable scraps, coffee grinds.) Add the items in layers to a compost container or pile. Turn once a month and you will have compost in 90 days.

Removing Salts

Potting soil that has been in a pot for a while will start to leach out salts. A white crust along the edge of the pot and on the surface of the potting soil is indicative of leaching salts. When this situation occurs, it is possible to refresh the potting soil; you just have to remove the excess salts.

Start by drilling a few holes in the bottom of a bucket or pail. Add the old potting soil to the pail and fill with water, allowing the water to completely drain out of the pail. Fill the pail a second time and allow all of the water to run through. Rinsing the soil helps to flush out the excess salts.

Empty the potting soil onto a tarp and spread it out in a single, thin layer. Place the tarp in the sun and allow the potting soil to dry out completely.

Sift finished compost through a half-inch screen. Mix the screened compost and potting soil together in a tub or trash can, using equal amounts of potting soil and screened compost. Moisten the mixture and allow it to cure for two to three weeks, making sure that it does not dry out. You can place the container in a shed or garage. If doing this during the winter, keep the refreshed soil from freezing. Allowing the mixture to cure will help the beneficial microbes from the compost to spread into the potting soil. You can give your plants an extra boost by adding worm castings or other organic fertilizer to the mix before allowing it to cure.

Refreshing your potting soil with compost is a great way to save money and to provide your plants with the best growing medium possible. Change out the soil in your planters once a year and you will be rewarded with beautiful, healthy plants.