Indoor Gardening: Growing Bulbs

MORE and more people are discovering the pleasures and interest of indoor gardening, not only those who live in town flats, often without balconies, but those with gardens too,

Keeping a room supplied with cut flowers is one way of bringing the garden indoors. But perhaps more satisfying is the cultivation of house plants, and the making of miniature gardens in bottles and various other kinds of container.


Bulbs grown indoors give special pleasure, since their development can be watched from start to finish, and their blooms appear at times when flowers in the garden are scarce. They are showy and beautiful, and often delightfully fragrant. Crocus

For forcing, choose bulbs that are solid, heavy, and free from blemish or mildew. They need not be top size, but make sure that the tips are undamaged and that the thin outer skins or tunics are reasonably intact. Be particularly careful about this when choosing tulips. Those that look skinned may have been roughly handled; such bulbs will probably do well enough in a garden, but avoid them for growing indoors.

Choose, too, bulbs that have been specially treated to flower at certain times of the year. A bulb normally requires a long period at low- temperatures after it has been planted, followed by warmth as it reaches the flowering period. By artificially simulating these natural conditions, through subjecting the bulbs to heat or cold treatment, growers are able to vary the length of the waiting period. In this way, a grower can dictate the time of year at which a bulb will bloom. It enables him to ship bulbs to any part of the world, and it enables the indoor gardener to buy, with confidence, bulbs that have been specially prepared to flower early (for example, at Christmas), or at specific times during spring or early summer.


Bulbs may be forced in many different kinds of container filled with one of a variety of growing media.

The beginner will probably wish to use flower pots filled with soil; to guard against over-watering, put a few crocks covered with leaves over the drainage holes. Bowls made especially for bulb-growing are filled with bulb fibre or medium grade sedge peat. One or two lumps of charcoal at the bottom of each bowl will give sufficient drainage. For crocuses there are special pots made of terracotta, with holes punchcd out at intervals round the sides. Fill the pots gradually with fibre and poke the tip of a crocus corm through each hole from the inside as the work proceeds; plant several more on the top. Each crocus pot holds about a dozen corms and makes a delightful picture when all come to flower, with blossoms round the sides of the pot as well as on top.

Most bulbs can be grown in soil, compost, bulb fibre, sedge peat, vermiculite, water or brick rubble, or even in bowls of wet newsprint.

The chief essential is to maintain an even amount of moisture. The planting material must never become waterlogged and never dry out. Food is of less consequence, since a bulb usually stores enough within itself to bring it to flower.

If soil is to be used, John Innes potting compost No. 1 gives excellent results. Alternatively, make up a mixture of equal parts of sifted loam, coarse sand and peat. The soil must be firm in the pots but not hard packed.

Bulb fibre can be mixed at home from sedge peat, a little crushed charcoal and oyster shell. But most nurserymen sell fibre ready mixed at a reasonable price; in some brands there is also a trace of fertilizer.

Soak the fibre before use, so that when squeezed in the hand only a few drops of moisture can be expelled; never let it swim in water. Half-fill the container and stand the bulbs in place, close to each other but not actually touching. Using the handle of a wooden spoon, pack more fibre round the bulbs until the smaller ones are completely covered and only the necks of hyacinths and narcissi are showing.

Do not twist any of the bulbs round and round to set them lower in the bowl, as this consolidates the fibre beneath them so that the roots cannot penetrate it and they therefore grow up-ward and over the rim of the bowl. Fibre, like soil, should be pressed firmly into the container but not packed hard.

Compost made from old newspapers is excellent for hyacinths. Newsprint (the material on which newspapers are printed) contains cellulose and has a natural tendency to hold moisture. To prepare a newsprint compost, first soak the newspapers well, then shred them into pieces the size of a pea. The compost is used in bowls in the same way as fibre.


When all the bulbs are planted, put them into a cold, dark place for eight to ten weeks to encourage good root formation, without which there cannot be success. Most bulb failures are caused by bringing the bowls too early into the light and warmth.

Ideally, the bowls should be plunged under a 6-in. layer of wood ashes, sand or soil in the garden. Wrap them first in polythene to save them from gelling scratched and to prevent heavy rain from flooding them.

If they cannot be plunged in a garden, the bowls should be stood in a cold, tireless place such as a cellar or cool cupboard. First wrap the bowls in black polythene, which keeps out the light and prevents them from drying out. Bowls wrapped in polythene will not need watering throughout the plunge period. If they are not wrapped, they should be looked at occasionally and supplied with sufficient water to keep the fibre just moist.

Examine the bowls from time to time. When the bulb shoots are about l in. high, root growth is sufficiently strong for the bowls to be brought in from the garden or taken from the cupboard. Remove the polythene wrapping, and then put them in a light, cool room, at a temperature of about 50° F. (10° C).

For the first day keep the bowls covered with newspaper to allow the white shoots to accustom themselves to the light. They gradually turn green and grow vigorously, but do not take them into real warmth—higher than 60° F. (16° C.) —until the leaves are well out of the bulbs. At this stage, water more frequently; how often depends on the heat of the room. Keep the fibre moist to the touch, but no wetter; if it is over-watered it will harden on top (repelling any further moisture) and dry out underneath.

A good idea is to sprinkle the container with Agroslis tenuis grass seed directly it leaves the plunge bed or the cupboard. By the time the bulbs come to flower, the surface of the soil or fibre will be completely hidden by a green turf carpet.


1.    Insufficient time in the plunge bed or cupboard, causing stunted growth.

2.    Leaving the bowls in a draught, which turns the leaves yellow.

3.    Insufficient water at the roots, which may result in dead blooms on the flower spike, stunted flower stems shorter than the leaves, or dead foliage.

4.    Insufficient light, inducing long, lanky and yellowing leaves.


A few bulbs, notably crocus, Narcissus Cragford and N. Paper White, can be grown entirely on water. The bulbs themselves must be kept just clear of the water (if they touch it they will rot) so that their roots can go down for moisture. It is not necessary to keep water-grown bulbs for a time in darkness. And their development can therefore be watched daily.

There are two methods of water cultivation. The most usual is in bulb glasses, which can be bought in various sizes. A bulb glass has a restricted neck in which the bulb perches, sending its roots down to the water below. Always keep a lump of charcoal in the glass.

Rain-water gives much better results than tap-water; even in a flat, rain-water can be trapped in a suitable container placed on a window ledge. Top up, too, with rain-water.

The other method is to pile washed pebbles in bowls or saucers with water in the bottom. The bulbs are lodged between the stones, which keep them from contact with the water.


Hyacinths. Most of the large-flowered hyacinths force well. They can be had in either white, red, yellow, pink or blue shades. Roman hyacinths bloom earlier, are smaller and daintier, and produce several spikes from a single bulb; the flowers are usually white, but there is a deep rose-pink variety called Rosalie. Most hyacinths should be planted in September or October.

Muscari. All need cool conditions. Daffodils and narcissi. Recommended are Golden Harvest, Carlton (clear yellow), Verger (white and lemon), and Valiant Spark (orange and yellow). For growing on pebbles the best are Cragford, Grand Soleil d’Or and Paper White.

Tulips. Most double tulips can be forced. Of the single varieties, choose for forcing those listed in bulb catalogues as single early. Potted in September and October, they will flower in January and February. Crocuses. All crocuses can be forced.

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13. February 2013 by admin
Categories: Indoor Garden, Types of Gardens | Tags: , , , , | Comments Off on Indoor Gardening: Growing Bulbs


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