Can you reuse potting soil after your flowers fade, temperatures drop, and you empty your containers and put them away for the winter? It’s tempting to keep and reuse what you have since replacing potting soil can be pricey, especially when you have a lot of potted plants. But this lightweight mix of compost, peat, perlite, and other materials doesn’t last forever.
Plants use up the nutrients in it as they grow, and the mix can become compacted and filled with roots. Sometimes pests, diseases, and weeds can take up residence, ready to pop back up when you replant in the mix. However, you can remedy these issues and get another use out of your potting soil with a little extra work.
It’s generally fine to reuse potting soil if whatever you were growing in it was healthy. But can you reuse potting soil that’s been home to pests? If you noticed pests or diseases on your plants, it’s best to sterilize the mix to avoid infecting next year’s plants. First, remove roots, grubs, leaves, and other debris from the old potting soil. Then, decide on the best method for banishing microbes and insects.
One technique for sterilizing soil is called solarizing. It involves putting old potting soil in lidded, five-gallon buckets ($7, The Home Depot) or black plastic bags tightly tied shut and leaving them in the sun for 4-6 weeks. The heat builds up inside the buckets or bags just enough to kill bugs and pathogens.
You also can sterilize old potting soil in your oven. Place it in an oven-safe pan, cover with foil, and bake it at 180 to 200 degrees Fahrenheit for 30 minutes (the soil will produce an earthy smell). It’s also important to check the soil temperature with a candy or meat thermometer ($23, Williams Sonoma) to make sure it stays below 200 degrees. Higher temperatures can release toxins. When it’s done, remove the soil from the oven and keep it covered until it cools.
Microwaving is another option. Put old, moistened potting soil in quart-size, microwavable containers. Cover them with microwavable lids that you can poke ventilation holes in or leave cracked to allow steam to escape. Heat at full power for about 90 seconds per two pounds of soil. Remove the containers, cover the vent holes with tape, and let the soil cool completely before using it.
Once your old potting soil has been sterilized, you’ll need to replenish its nutrients. You can combine equal parts of new potting soil with the old and add a dose of slow-release fertilizer pellets ($19, The Home Depot) according to package directions. Or, you can mix in one part compost to three or four parts of your old potting soil. Besides adding nutrients that plants need, fresh potting soil and compost will help keep the mix from compacting.
Reuse your clean potting soil in containers for vegetables, flowers, houseplants, or whatever you’d like to grow. If you’re not up for sterilizing and refreshing old potting soil, you can still put it to use instead of throwing it out. It can be dumped directly out of your containers and into established beds and borders. You can use it in raised beds or wherever your yard has holes or eroded areas. It can also be mixed into compost piles. The old potting soil you reuse can help you save money for what all gardeners want: more plants.
It's generally fine to reuse potting soil if whatever you were growing in it was healthy. But can you reuse potting soil that's been home to pests? If you noticed pests or diseases on your plants, it's best to sterilize the mix to avoid infecting next year's plants.
However, if the plants that grew in the soil before were healthy, it is generally OK to reuse the potting soil. One way to be sure that soil is clean is to sterilize the soil. There are a couple of ways to sterilize the soil. One is to solarize the soil in the sun, and the other is to heat up in an oven or microwave.
3. How Long Can You Store Potting Soil? Opened bags of new potting soil can retain quality for around 6 to 12 months. For unopened and unused potting soil, you can store it for about a year or two before it goes bad.
Typically, changing the soil in your potted plants should happen every 12 to 18 months. There are some exceptions that may change this timing. These include if you're moving a plant into a bigger pot because it's outgrown its current pot or if the soil has become very hard.
Hillock cautions gardeners against reusing potting soil if they had problems with diseases, weeds or insects last year. Viruses, fungi and bacteria will remain in the potting soil long after the life of the plant. “It's possible to destroy these pathogens, but it isn't worth the risk.
That potting soil is worn out because the peat moss has decomposed. That peat moss can decompose even if you never take it out of the bag. If your potting soil has been sitting in your shed since last year in an opened bag and it's gotten wet, toss it.
If your potting soil starts to smell sour, foul, or rotten, it's a sign that the soil has likely gone anaerobic due to overwatering or poor drainage. Anaerobic conditions can be harmful to plant roots and hinder plant growth.
Thankfully, there is one method that will consistently rewet super dry potting soil; wetting and mixing it with very warm or hot water and then hand turning and mixing it (be sure to wear water-impermeable gloves). The heat helps the peat and compost easily take up water again.
Their texture and weight allow less air movement, which is why they can get easily compacted. Water drains slower. This quality makes it not the best choice for potted plants since they can get wet roots, harming your house plants. Not perfect for seed starting.
As long as used potting soil still looks fairly fluffy and doesn't emit a rotten odor, gardeners should be able to use it again with good results. However, if the plants formerly grown in the potting soil struggled with disease or insect problems, it's probably best to discard the mix and start fresh next season.
For instance, if the container is so large that the volume of soil is a lot like a raised garden bed you could simply top with compost— mixing it gently into the top layer and then transplant. A second option for reusing old potting soil and refreshing a container is to empty out the whole thing and remix the soil.
Add a handful of a slow release fertilizer like manure. Mix in one part compost for every three or four parts of the old potting mix. Apply a liquid fertilizer like compost tea every two weeks. Mix an organic fertilizer like worm castings or coffee grounds to the top few inches of garden soil.
If it appears healthy, you can revitalize it by amending with fresh compost or organic matter to replenish nutrients. Sterilization: To reduce the risk of pathogens or pests, you can sterilize the old potting soil by heating it in an oven or microwave, but be cautious not to overheat or burn it.
Plants may appear wilted and thirsty, but take care to refrain from watering until about a week after re-potting to ensure that any roots damaged during re-potting have healed. During the recovery period, place plants in a cooler, shadier spot. Most potting soil contains fertilizer.
As long as used potting soil still looks fairly fluffy and doesn't emit a rotten odor, gardeners should be able to use it again with good results. However, if the plants formerly grown in the potting soil struggled with disease or insect problems, it's probably best to discard the mix and start fresh next season.
As old soil might be deficient in plant nutrients, you need to replenish it. Here are some ways you can add nutrients and organic matter to soil: Add a handful of a slow release fertilizer like manure. Mix in one part compost for every three or four parts of the old potting mix.
Introduction: My name is Saturnina Altenwerth DVM, I am a witty, perfect, combative, beautiful, determined, fancy, determined person who loves writing and wants to share my knowledge and understanding with you.
We notice you're using an ad blocker
Without advertising income, we can't keep making this site awesome for you.
:strip_icc()/hands-in-potting-soil-e7f271a0b638489bbfa65ae65f779e53.jpg "Can You Reuse Potting Soil? Yes, as Long as You Do This First (1)")
