Reusing the soil right after the harvest?

The golden rule............new plants = new soil!. Saving money by reusing old soil is false economy, the risk of disease and salt/pH problems is too high. Why risk the results of your next grow by penny pinching on something as vital as quality soil mix?

I re-used soil (FFOF+extra perlite) 3-4 times wheni first started... No problems but doesn't mean i had zero risk.. just too new to know better. As long as it isn't over-fertilized should be fine. The rotting old roots and such could impacat pH or be a foothold for some sort of pathogen. Can you do it? more times than not probably okay, but it is better to at least strip out off the old roots system, which in my opinion is not worth the effort, but each to their own. If you compost, that's an option too.

Best to compost it or sanitize it somehow like with heat or chemicals like peroxide. easier to do outdoors in black garbage bags or an old oven. I tend to mix all my old soil into my current garden and call it a day. any extra I toss into city planters at night.

One technique for sterilizing soil is called solarizing. If you are unsure about health. It involves putting old potting soil in lidded, five-gallon buckets (available at 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.

As long as used potting soil still looks fairly fluffy and doesn't emit a rotten odor, 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. Make sure to replenish using organic amendments if you use them. Old roots are the the issue. Remove bigger roots by hand. I like to have a bone dry period over a week or two then re-moistureize. Once done use a humic acid this will help with any roots that were left over decompose faster.

Hey, i would suggest to remove as many old roots as you can before re-using soil, as they can become a breeding chamber for pests like fungal root infections. You could also cycle your pots, the roots will decompose over time (it takes patience, you should wait at least 1 year, better 2 or 3) and meanwhile you can plant any other plant than cannabis or hops into that soil. The roots of another plant species will not be problematic, just from the same species or family its dangerous to plant into rotting roots. If you consider this you can recycle your soil. Make sure to reamend what you estimate has been taken from the soil in the previous grow. Good luck!