Growing Bulbs

Growing Bulbs for Cut Flowers

Cut flowers that are taken from bulbous plants have a big marketing advantage over other types of flowers. They provide the grower with two products to sell.

While the flowers can be sold as a cash crop; flowers do not keep for a long time. They must be sold when  they are ready to pick. The grower can also sell the bulbs as well though; and the bulbs are less time sensitive. They enter a period of dormancy after flowering, when the top dies down. The dormant bulb can be lifted, and if stored properly, can be kept for a long time, and sold over a period of months; sometimes many months.  Two products is a distinct advantage; but having a product that is not so time sensitive is an even greater advantage.

Additionally, bulbs can be transported easily. They can be packed in boxes, sold through the3 mail; stored dry on nursery shelves, etc.

A true bulb consists of swollen fleshy or scale like leaves or leaf bases arising from a basal plate. Most home gardeners however, generally refer to bulbs as those plants which store food in a part of the plant below the ground. This includes the true bulbs, corms, tubers and some swollen rhizomes. These types of plants provide some of our most spectacular flowering displays. Some are also very fragrant.

A swollen root or bulb does not need heavy feeding when first planted as it will initially utilise its stored food supply. Because they are all grown for flowers, they generally need larger amounts of potash than other nutrients. They usually also have a dormant period and can be susceptible to rotting if left in a moist situation during dormancy (ie. their metabolism is slow in dormancy...this means their defence mechanisms are lower).
Most bulbs prefer a rich, organic, well drained loam. They thrive on soil which has been prepared with rotted manure or compost prior to planting.
Sunny but cool positions are excellent. They can often burn if there is too much heat or wind.

You can grow bulbs anywhere, any time, but you need the appropriate type for your locality.
Though most common bulbs are grown in temperate climates, some only do their best in a tropical climate

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, etc. This can occur if the bulb is not particularly hardy in your climate, or if you apply irrigation water at times of the year when the bulb is used to experiencing dry conditions. For this reason many bulbs are lifted and stored in a clean, dry and dark place to protect them from deteriorating.

Some bulbs however, do not benefit at all from lifting. It disturbs their root system and can even result in the death of the plant.

HOW LONG DO THE FLOWERS LAST?
Some bulbs produce flowers continually over a period (eg. Day lilies can flower for many months, particularly in warm temperate to tropical areas)
Others produce only one flower per bulb each year (eg. Daffodil, Tulip); and for an extended show, you need to plant a large number of bulbs.

FERTILISING BULBS/PLANTING BULBS
When you first plant out bulbs, you should provide them with a friable soil that has been fertilised with compost and/or an organic fertiliser. Bulbs will not grow well in heavy soils with low nutrients.

The best time to fertilise bulbs that become dormant is after they have flowered. It is during this time that they store the energy that they will use to produce flowers in the following year. It is for this reason that you should only remove the old leaves from bulbs when they are no longer green. If you have not removed the flowers to use in flower arrangements, it can also be beneficial to remove the spent flower heads, as this will prevent the plant from putting its energy into seed creation.

If you want your display of single flowering bulbs to last a little longer – plant half the bulbs upside down. That way it takes longer for the shoots to break the surface and consequently for the bulbs to flower.

Always make sure that you plant bulbs to the recommended depth.
*If you plant them too deep their shoots may not reach the surface
*If you plant them too high they will topple over once they begin to grow
*Ensure that the soil is both friable and firm to allow root penetration and stability of the emerging plant

LIFTING BULBS OVER WINTER

Many summer and autumn bulbs can benefit from lifting out of the ground and storing dry over winter.

Bulbs and other underground plant storage organs such as tubers and rhizomes become more susceptible to water-logging and attacks from pests and diseases in cool, moist conditions. In areas that have cold, wet winters bulbs will need more regular lifting than in other places. The need for lifting also varies with the type of bulb: some are more sensitive than others and require extra care.

Once the foliage begins to die down, you should generally stop watering. Liquid fertiliser can be applied to increase the bulb’s nutrient store.

Let all the leaves die before you dig up the bulb. This may look untidy, but it is important for the plant to be able to store food in the bulb for next season. Some gardeners plait the leaves together to keep them looking tidy while they die back.

When you dig up the bulb or tuber take care not to damage it with the spade or fork. The best way to lift bulbs up is to push two spades into the ground about thirty centimetres either side of the bulb clump and whilst supporting it from beneath, lever it out of the ground. Wash the soil off with a firm jet of water then let the bulbs dry completely before storing.

The most effective method for storing bulbs is to put them into net bags and place them somewhere cool, dry and airy – a dark, cool corner of the garden shed is ideal. Dust the bulbs with a fungicide powder and don’t overcrowd the bag as this can encourage fungal diseases.

There are other methods to store bulbs. For example, you can layer them in dry peat, vermiculite or clean, dry sand in a mesh or paper bag in a cool dry location. Check them once in a while during the winter and throw away any soft ones. The main thing when storing bulbs is to keep them dry. The bulbs will dehydrate, and may look wrinkled & pretty pitiful by spring, but that's you want.

If bulbs aren’t lifted, flowering may decrease over the years, or worse still, the bulbs may die. With proper handling and care, bulbs will multiply and improve over the years. Remember to think about climate, the type of bulb and the general garden conditions: with these things in mind, you can achieve maximum flowering with a minimum of work.

Summer flowering bulbs that benefit from lifting
Calla
Dahlia
Lilium
Nerine
Begonia
Eucomis
Galtonia
Hippeastrum*
Agapanthus*
Watsonia*

*Note: the main reasons to lift these bulbs would be to divide clumps or to avoid extreme cold (such as deep snow). These bulbs will survive if you don’t lift them.

Autumn flowering bulbs that may benefit from lifting
Crocus
Dahlia
Iris (some)
Lycoris
Nerine
Colchium
Leucojum
Sternbergia