Can I use the compost from grow bags in pots of spring-flowering bulbs?
Wyatt Newman, by email
Stefan says: Yes, you certainly can, and this raises an interesting issue that I’ve been thinking about now we’re in the bulb-planting season. I used to refill my bulb pots every year with fresh compost but soon realised this was a waste of both time and money. Many people may think me extravagant because while I keep bulbs in the open ground for several years – three or four years at least and truly naturalised kinds much longer – I treat bulbs in pots as annuals and discard them after flowering, when the pots are refilled with summer plants. But because the bulbs are only being grown for one season, they have no need for nutrient-rich compost because all the food they require is contained in the bulb itself. So almost any compost will suffice, even if it has been used for other plants.