Do you have an urban garden, many pots or crops on your terrace and want to know if you can? reuse old substrate for your plantsThe answer is yes. Recycling and reclaiming used soil is a sustainable and economical way to keep your crops healthy, avoiding waste and protecting the environment. However, it's essential to follow certain steps to ensure this substrate is once again fertile and safe for your plants.
Why does old substrate lose quality?
Over time, the substrate of pots and growing tables loses nutrientsIt compacts and can be a breeding ground for pests and diseases. Although it may appear to be in good condition at first glance, it's probably lacking minerals and its physical structure has deteriorated.
The main problems when reusing old substrates are:
- Nutrient deficit: Plants deplete the minerals and organic matter present in the substrate, leaving the soil less fertile.
- Compaction: Continuous watering and the effects of time cause the substrate to lose its natural sponginess, making aeration and drainage difficult.
- Presence of pests and diseases: There may be larvae, insect eggs, fungi, or bacteria that survive in the soil and affect new plants.
Steps to prepare and improve the substrate used
The process of restoring old soil to life is simple, but requires attention to several details. This way, you can restore the substrate's structure and fertility and avoid potential problems for your new plants.
1. Sieving and cleaning
Pour the old substrate into a large container and pass it through a sieve. This will separate Dead roots, stones, pieces of bark, dry clumps and possible remains of pests or larvaeThe finer the substrate, the better the aeration and water retention capacity.
2. Aerate and restore texture
If the substrate looks compacted or dry, it needs to be restored to its optimal structure. You can add coconut fiber, perlite, vermiculite, or volcanic gravel. These materials increase porosity, promote drainage, and improve moisture retention, preventing excessive compaction.
3. Enrich with nutrients
Since most of the nutrients have been consumed or washed away by the water, you need to replenish them. Mix in a ratio of approximately two parts old substrate to one part new substrateIf you want a more sustainable alternative, you can use Mature compost, worm castings, well-rotted manure, or slow-release organic fertilizersThese improve fertility and reactivate the microbial life of the substrate.
Tip: If you grow species with high nutrient demands (solanaceous plants, for example), you will also need to add a complete fertilizer later, as maintenance.
4. Disinfection of the substrate (optional)
If you suspect pests, fungi, or diseases, disinfection is essential. There are two safe and effective methods:
- Heat sterilization: Bake the substrate for 30 minutes at a moderate temperature (around 140°C) to eliminate pathogens.
- Solarization: Spread the substrate on a sheet of plastic and expose it to direct sunlight for two to three weeks, completely covered. The heat kills eggs, fungi, and bacteria.
After these treatments, it is advisable reintroduce beneficial microorganisms adding compost, worm castings or specific products to regenerate the essential bacterial and fungal life of the soil.
What to do with stored bags of substrate
It tienes unopened bags of substrate from the previous season, you should check them before using them. Even if they are sealed, they may have lost some of their nutrients or accumulated excess salts, which can negatively affect the plants. It is best to mix them with new soil or compost following the steps above, to restore a correct nutritional balance and avoid salinity problems.
Additional tips for a longer-lasting and healthier substrate
- Aerate the substrate regularly stirring it with a shovel, thus promoting oxygenation and avoiding compaction.
- Practice crop rotation to minimize the occurrence of diseases and balance nutrient intake.
- Do not reuse substrate with serious pests for sensitive plants. In this case, use this substrate in compost or for mulching in ornamental gardens.
- Try amendments such as compost scraps, rock flour, or shredded plant material. to improve the structure and enrich the substrate.
Giving your old soil a second life is possible and highly recommended, both for your wallet and the planet. Restoring the soil, disinfecting it when necessary, and enriching it with organic matter allows your plants to obtain all the nutrients and the proper environment to grow strong and healthy, without having to discard the old soil. This way, you can enjoy sustainable, ecological, and efficient gardening, ensuring abundant and attractive harvests season after season.
