... ammonium, potassium, calcium and magnesium.ยท Vermiculite, when combined with peat or composted pine bark compost, promotes faster root growth and ... in weight, easy to handle and easily mixes with soil, peat, composted pine bark, fertilizers, pesticides and herbicides. Its ... SEED GERMINATION - Use vermiculite alone or mixed with soil or peat. Very little watering is required. More seeds germinate - ...