Vermiculite is a sterile growing medium which can be used for directly sowing seeds into or as a small top layer on your usual seed compost. Vermiculite can also be added to potting on compost to improve aeration and uptake of nutrients.
Vermiculite is often used to help prevent "damping-off"; this is caused by a fungal infection and damages new seedling stems.
If you sow directly into vermiculite, due to it's sterile nature, you will need to provide liquid feed.
When we sow the chilli seeds for our main crop, we sow them very densly in 7.5cm (3") pots and just cover the seeds with 5mm of vermiculite. This helps to keep moisture around the seeds and also helps insulate them against fluctuations in surface temperature.
When we are pricking-out and potting-on, we add a few handfuls of vermiculite to a bag of compost to help prevent nutrients from being washed out - the vermiculite then releases moisture and nutrients to the plant roots.
Size - Small (10Ltrs).
Please note, the brand of vermiculite may vary from the picture shown and may not be in a re-sealable bag.