ACS Distance Education UK
In many locations, it is better to plant winter-flowering bulbs, earlier rather than later in autumn.
In cooler places though, it may be better to plant them later.
It is important to remember that most bulbs don't like to be in hot soil. Try to choose plant types which come from a climate similar to where you live.
In some warmer places you may need to wait until the hotter weather has passed completely before planting. Generally speaking, plant bulbs later in hotter climates than recommendations for temperate regions.
Early autumn is also the best time for planting those spring-flowering bulbs with softer, fleshier bodies because they are more prone to rot if removed from the ground for too long. Some other bulbs may be planted in early autumn to provide earlier spring flowers.
How to Plant Bulbs
As a general rule of thumb, most bulbs are planted at twice the depth of the size of the bulb (so, a 2cm bulb is planted 4cm deep). The same applies to space between bulbs, although you can plant further apart if you intend to naturalise bulbs over time (this gives them more space to multiply before you need to lift and replant them because of overcrowding).
Some bulbs such as tulips for example, need a chilling period to initiate flowering. Buy these early and store them in the fridge (not the freezer) for a few weeks before planting out in the garden.
Bulbs can be planted using a trowel to dig a hole which is deep enough and wide enough to accommodate the bulb. The bulb is placed in the hole with the basal plate (i.e. the bottom of the bulb) resting on the bottom of the hole. The hole is then backfilled with soil and gently firmed down. Cover the soil with a thin layer of mulch (pea straw, manure or fine bark are ideal) to conserve moisture.
Bulbs thrive in rich, free-draining soil which has been prepared by adding rotted organic matter. They will not grow well in heavy soils with low nutrients. If you do have heavy soils, plant them in raised beds or pots.
Bulbs usually have sufficient nutrients stored within them to produce flowers and don't need additional feeding at planting, however growth will be stronger with good soil fertility.
If you do need to fertilise, a slow-release fertiliser is more appropriate for bulbs. Use this if you have particularly sandy soils. Avoid applying strong fertilisers directly onto tender tissues (young leaves, new roots) or dormant bulbs.
Organic fertilisers are mostly slow-release, as are pelletised fertilisers or anything that does not dissolve readily and thoroughly in water.
Why Lift Bulbs after Flowering?
For many bulbs, the foliage dies down after flowering, leaving only the dormant bulb in the soil. While in this dormant state, some bulbs are susceptible to rotting, attack by pests, or damage by fertilisers, chemicals in the soil or soil-borne diseases. These bulbs may be lifted and dried in a cold, dry place before wrapping in cloth such as hessian and stored ready for planting the following autumn. It is essential that the bulbs are dry before storage otherwise they are prone to moulds. Always allow the foliage to die back naturally before lifting otherwise the bulb may not have stored sufficient quantities of food. In most cases though this is not needed in our Australian climate.
SOME BULBS TO GROW
Lilies do well in cooler areas and are just as well suited to mass plantings and garden beds as they are to woodland gardens.
These do well in most climates, with the exception of tropical areas.
Tulips grow well in most regions but many usually only flower well in the first year.
These come from South Africa and do well in most parts of Australia, England and similar climates.
Alliums include lots of edible plants (onions, shallots, some types of garlic), plus others only grown for flowers. All are treated similarly.