Besides Aspidistras, you can have some of the hardy Ferns, of which the Holly Fern is the most enduring; Aralias, which look like little Fig-trees; Indiarubber plants, whose young unfolding leaves it is such a pleasure to watch; various hardy Palms (Phœnix and Kentia, for instance); and some of the hardy Cactuses. The Indiarubber (Ficus Indica) and Palms are plants that you must be careful not to overpot. We know that from sad personal experience, as well as from some of the great authorities. In our early gardening days we often used to get a healthy Palm or Indiarubber from a good nursery, thinking when we bought it that the nurseryman was rather stupid and neglectful to leave the poor thing caged in that little pot of hard soil. We would bring it home, turn it out, find its roots in a thick mat, plunge them into a pot about four times the size of the old one, full of nice, loose, fresh soil, and expect it to grow like Jack’s Beanstalk in its happy new conditions. The ungrateful thing usually died. So remember that if you repot Indiarubber plants and Palms at all, take a pot only slightly larger than the last. Remember, too, that if you overwater an Indiarubber plant its leaves will turn yellow and drop off, while Palms must not be allowed to suffer from drought. It is death to nearly all plants to be allowed to stand in stagnant water. We mean that you must not leave the water in the saucer that has run out of the pot. When a plant is dry it is a good plan to plunge it in water nearly, but not quite, up to the brim of the pot, and to leave it there till the top of the soil is moist. That will show you that it has had enough to drink, and it should then be lifted out and allowed to drain before being replaced in its saucer. If you let plants stand in stagnant water day after day, they soak up more than they can digest—their leaves turn yellow, their roots rot, and they die. You can generally judge by the state of the pot whether you should give water. At least we know one good amateur gardener who would never water a plant in a moist pot, but only one in a pot that felt dry to the touch.
All foliage plants must be sponged once a week with a soft sponge and lukewarm water, as dust chokes and kills them. If you can put them out on some leads after sponging and spray them well with a syringe, so much the better, but this must be only done in mild weather. Remember, too, not to use ice-cold, hard water from a tap. In summer let them stand out in soft warm rain as often and as much as possible.
Many plants in pots die of starvation. When you drench them with water, the water that runs off carries plant food with it, and this is often not replaced. We used to use a little Clay’s Fertilizer, about half a small teaspoonful to a half-gallon of water, well mixed; but lately we have used Shefa, a new kind that is especially suitable for ferns. These liquid manures must never be given more than once a month, and never to flowering bulbs.
If you have more plants than will stand on your table in the window, you must shift some of them every week, and bring those that have had several days of semi-darkness to the light. You must also be careful not to let your plants stand in a draught. It is most injurious to them, especially when it is a cold one. If you have a light bathroom, with a good-sized window, and are allowed to use it, you would find it a help, as the air of a bathroom is sometimes steamy, and never as dry as that of a sitting-room. You could put plants that you wanted to nurse there, and more especially a succession of bulbs when they have made their roots in darkness and first need the light.
The real joy and glory of room gardens are the flowering bulbs, and the more you can have the better; but grow a few of many kinds rather than many of a few kinds, because then you will have a longer and more continuous succession. You do not want your room over-crowded at one time, and then empty of scent and colour. In September you should muster your glasses, bowls, and pots, and decide what you want and can afford to buy, and you must also choose what you will grow your bulbs in. Hyacinths, as you no doubt know, do well in water, and nowadays you can buy pretty squat glasses instead of the ugly tall ones we used to have. The bulb should almost, but not quite, touch the water; if it gets sodden, blue mould forms on it, and it decays. Crocuses are also grown in water in small glasses sold now for this purpose. The early Roman Hyacinths and the Polyanthus Narcissus will also flower well in this way. When you grow bulbs in water you will find that you must often add a little. The amount a Hyacinth in flower will drink is surprising. Many people change all the water in their bulb glasses once or twice in the season. A scrap of charcoal in each glass keeps the water clean and wholesome.
Many mixtures for growing bulbs are recommended. The one we like best for bowls without drainage is gravel mixed with a little carbon. You buy it in little sacks mixed ready for use at any of the big London shops that have a gardening department, and probably at any good florist’s elsewhere. Moss-fibre is satisfactory, too, but the gravel is cleaner to handle, and the carbon keeps the water sweet. From the moment that bulbs are planted in bowls they must not be allowed to become quite dry. If you think there is too much water, however, you must put your hand over the top of the bowl to keep your bulbs in place, tilt it a little, and drain off the water. For ordinary flower-pots a mixture of leaf-mould and sand is good, and while these are in the dark you must not water much, or the soil will get sour and unhealthy. In planting bulbs for a room garden, do not set them deeply in the gravel or moss-fibre. The point of the bulb should just show above ground. This applies also to bulbs grown in ordinary pots. Whatever medium you use should be damp when you finish your planting. Your bulbs must then be put into a dark, cool place for four weeks to make their roots. An airy cellar is good, but many people use a cool cupboard. They usually choose one that is sometimes opened, and therefore aired for a moment. At the end of the four weeks the bulbs must be brought into a light and cool, but not cold, place, and it was at this stage that we found a bathroom window so useful. When the green is well up and the flowers beginning to show, they may be moved to a light place in your warm sitting-room.
The first bulbs to push up are the white single Roman Hyacinths. These, if planted in September, will bloom in November, and will give you a little of the promise and fragrance of spring in the dull, dark days. Two dozen bulbs would be enough to buy, and of these one dozen should be started in September and the other dozen in October for succession. Next come the red and yellow Duc Van Thol Tulips, Crocuses, Trumpet Daffodils, and Hyacinths. The two earliest Daffodils are Trumpet-Major and Sir Henry Irving, and they should be planted in September. The Hyacinths look well either singly in glasses or three together in a bowl. In October plant some of the later Daffodils—for instance, Golden Spur, Princess Victoria, Emperor, and Empress. These may all be treated in the same way: set in gravel with a little carbon added, kept from frost and in the dark for four or five weeks, then brought to a cool, light place, and, when in bud, to the warm room. The Japanese Sacred Lily, which is so largely advertised, is only a large kind of Polyanthus Narcissus. It is easy to grow in a sunny window; but we should always buy Narcissus Gloriosa instead, as it is very like it, just as sweet, and about a quarter the price. All these Polyanthus Narcissi bloom well in pots without drainage, and if you have a blue-and-white bowl you should fill it with the one called Soleil d’Or. Scilly White, too, is easy to grow in a room.
So far our description of the room garden has dealt with foliage plants and spring flowers, but there are also many summer flowers that do well in a light window. In most parts of England the cottage windows show you that. For instance, you often see the blue or white hanging Campanula Isophylla, such a mass of flower that it covers the pot. It is an easy plant to manage and propagate. If you get a healthy specimen of it in May, it should flower all the summer. In the autumn cut it back a little and give a mild dose of liquid manure. It will flower for years without being repotted, and can be increased by cuttings put round the edge of a pot and stood in a window. Gardeners always put anything they want to strike near the edge, and not in the middle of a pot. Begonias make handsome room plants; so do Fuchsias, Heliotropes, and Geraniums. We have seen a big plant of Heliotrope that had lived for years in a Paris window, but it does not like the sooty air of our big cities. Some of the vigorous Ivies grow well in pots, and in Germany you often see them trained round picture-frames. We once brought a spray from the country that was so determined to grow that it rooted itself in an earthenware jug, lived for more than two years on an occasional drink of fresh water, and only died when we were away from home and could not attend to it. Geraniums would rather be dry than wet. The pretty white Spiræa and the little trailing yellow Musk are both very thirsty plants, and flag at once if you neglect them. The Vallota Purpurea, the Scarborough Lily, is a splendid window plant. When once you have potted it you should not disturb it, as it flowers best when it is almost bursting the pot with its big onion-shaped bulbs. The Vallota never cares to be wet, and after it has flowered it needs very little water; yet it must not become bone-dry. You will say these are difficult directions, and we can only agree with you. Gardening is an art that in the end must be largely learned by experience, and the earlier you begin to practise it the sooner you will find out some of the things all the books in the world cannot tell you. You cannot give a recipe for watering as you can give one for a cake or a pudding, because the same plant will need different quantities in different conditions and at different times. When you see leaves flag in their flowering season, they probably want water; when they turn yellow and drop off, they have probably had too much. In winter you must not water in a room likely to feel frost at night, as that would help to freeze the roots. You are sure to have some failures and some successes with your plants to the end of your gardening days, but every failure ought to teach you, and every success will spur you on. The true gardener loves his art so well that he will grow what he can even under difficult conditions.