Autumn gardening - Spring bulbs

You need to plant spring-flowering bulbs in early autumn, preferably by the end of September because this is the month when many bulbs that are established in the ground begin to develop new roots, with one exception, tulips are best planted in November. Because most bulbs are purchased and planted when dry, which means they are dormant, leafless and rootless and need to be planted as soon as possible or they may flower poorly following late planting or lengthy storage. Another reason bulbs are planted in the autumn is to expose them to the cool temperatures which trigger a biochemical process within the cells of the bulb that stimulates flowering. They need at least six to eight weeks of temperatures of 40 to 45 degrees or lower and if they don't get this thorough chilling, flower stems remain short, and the flowers are produced close to the ground. This is why spring bulbs are so often disappointing after a middle winter.

Many hardy bulbs are from dry summer climates and prefer a warm sunny site with good drainage, but bulbs from cool, moist woodland habitats need similarly good damp garden conditions.

For all bulbs - make a hole to the required planting depth plus an inch. Fork in some bone meal if you use it, then an inch of sharp sand or grit to provide drainage which stops the bulb rotting. Space them at least twice the bulb's own height and width apart and replace the soil and gently firm with the back of a rake. As a rule of thumb you should plant any bulb at two or three times bulb height, which means the tip of a two inch tall bulb should be four to six inches below soil level.

Spring bulb photograph by Sailor Coruscant, used under a creative commons attribution licence