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Choose quality non-hardy bulbs

Choose firm bulbs with a smooth surface (here, Acidanthera bulbs)
Photo: Kevin Payravi
Gladiolus murielae, bulbs

Bulbs can be bought at nurseries, gardening centres and many supermarkets. They are usually available during planting season. Here are some things to consider when choosing bulbs, their site selection, when planting and maintaining them.

How to select bulbs

Here are some selection criteria.

  • Large, firm and relatively heavy bulbs with a smooth surface are preferable.
  • You should avoid bulbs that are damaged, mouldy or insect-infested.
  • It is better to buy a small number of good-quality bulbs, which will produce large flowers, than a large quantity of cheaper small bulbs.

Even if they are in good condition when they are bought, bulbs can deteriorate very rapidly. They must be stored in a cool dry and well-ventilated place until they are ready to be planted. In general, tender bulbs are planted outside as soon as any danger of frost is over, i.e. at the end of May or early June.

Which site to choose?

In order to achieve good growth and interesting blooms, bulbs should generally be planted in a sunny area. They can be placed near a low wall, a staircase or in a rock garden. Their appearance is most striking when planted in small bunches.

Planting and maintaining non-hardy bulbs

Soil preparation

Bulbs prosper in rich and well-drained soil.

It is advisable to turn the soil and to enrich it with humus, i.e. compost or composted manure. Soil with a neutral or slightly alkaline pH level (6.5 to 7.5) is ideal. The pH can be determined with a soil test.


When the bulbs are planted, a bulb fertilizer will provide the necessary phosphorus for the bulbs to take root properly. Later, when the buds appear, a fertilizer for flowering plants can be applied. It is important not to exceed the amount of fertilizer recommended by the manufacturer, because any excess may burn the plant.

Fertilizing is a very important factor in bulb growth because it strengthens the roots and enables the bulb to acquire new reserves for the following growing season.


The other important factor is watering. The soil should be well moistened to allow the roots to develop normally. Substantial watering before and after blooming will produce larger bulbs. The first few centimetres of soil should be watered and then left to dry before watering again. During the flowering period, the soil should not be left dry.

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