Foundations of our plantings - soil, composting, container gardening

[Agony]

7. re-using soil

Be extremely careful about reusing soil if you are talking about starting seeds or for small "pricked in" seedlings because you might have problems with "damping off". With damping off your tiny seedling rot off right at the soil surface, fall over and die. This is caused by fungal organisms that don't normally cause serious problems with larger or mature plants but manage to attack the very soft tissue of new seedlings. High moisture levels at the soil surface from watering (e.g.) can trigger this and suddenly all of your plants just fall over! This is why seeds/seedlings are often grown in sterile soilless mix. Growers use steam to sterilize soil, and you can use your oven or solarization to do small batches. (solarization is done by covering a container of damp soil with clear plastic and letting the sun get the temperature up above 100degF, 117deg can kill the relevant pathogens in as little as 6 hours)

most importantly!
have fun.

Cheers
Agony