Garden Types Of Bulbs – Many of the popular bulbs which flower in the garden during the spring months can be grown indoors. For many people, helping to plant up a bowl of tulips or hyacinths was their first introduction to the world of indoor gardening.
There are two basic growing techniques. Large bulbs are nearly always ‘forced’ so that they will bloom well ahead of their garden counterparts – this forcing technique involves keeping them cold and dark to make the roots grow and then providing more light and warmth for leaf and flower development.
Hyacinths are the most reliable, tulips the least satisfactory. The second growing method (the non- forcing technique) is used for small bulbs and is simpler than forcing. The pots are placed outdoors after planting and then simply brought indoors when the flower buds have formed and are ready to open. In this case flowering will only be a few days ahead of similar bulbs grown in the garden.
Forcing technique for hyacinths, tulips and narcissi
Planting: Choose varieties which are recommended for indoor cultivation and make sure that the bulbs are good-sized, disease-free and firm. Bulb fiber is sometimes used as the growing medium, but if you intend to save the bulbs for garden use after blooming then choose seed and cutting compost. Place a layer of moist compost in the bottom of the bowl and set the bulbs on it. They should be close together but must not touch each other nor the sides of the bowl. Never force bulbs downwards into compost. Fill up with more compost, pressing it firmly but not too tightly around the bulbs. When finished the tips should be above the surface and there should be about 1/2 in. between the top of the compost and the rim of the bowl.
Care after planting: The bulbs need a ‘plunging’ period of complete darkness and a temperature of about 40°F. The best spot is in the garden covering the bowl with about 4 in. of peat. Failing this, place the container in a black polythene bag and stand it in a shed, cellar or garage. Any warmth at this stage will lead to failure. The plunging period lasts for about 6-10 weeks. Check occasionally to make sure that the compost is still moist.
Care during growth: When the shoots are about 1-2 in. high move the bowl into a cool room indoors – 50°F is the ideal temperature. Place in a shady spot at first, then move near to the window after a few days. The leaves will now develop and in a few weeks the flower buds will appear. Now is the time to move the bowl to the chosen site for flowering. This spot should be bright but not sunny, free from draughts, away from a radiator or heater and not too warm; 60°-70°F is the ideal. Keep the compost moist at all times. Turn the bowl occasionally so that growth will be even and provide some support for tall-flowering types. Feed with a liquid fertilizer.
Care after flowering: Cut off flowers, not flower-stalks. Continue watering and feeding until leaves have withered. Remove bulbs and allow to dry, then remove dead foliage and store in a cool dry place. These bulbs will not provide a second display indoors – plant in the garden in fall.
Non-forcing technique for other bulbs
Planting: It is essential to choose a container with adequate drainage holes. Place a layer of crocks at the bottom and add a layer of bulb fiber or seed and cutting compost. Plant the bulbs closely together and add more compost. The tips of the bulbs should be completely covered.
Care after planting: Place the pot in the garden.
Care during growth: When the plants are fully grown and flower buds are present bring the pot indoors to the site chosen for flowering. Treat in the same way as forced bulbs.
Care after flowering: Treat in the same way as forced bulbs.