Westland bulb planting and potting mix is a specially blended peat-free compost ideal for indoor or outdoor bulb planting. With high grit for open drainage, it includes added zinc complex to naturally support plant health. Zinc aids production of the plant growth hormone auxin, which transports water and nutrients around the plant boosting growth of roots, shoots and flowers. It also encourages photosynthesis for energy production. Contains 10 litres when packed.