This section is from the book "The Gardener V1", by William Thomson. Also available from Amazon: The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener.
The common garden Balsam is now one of the most beautiful of our summer decorative annuals. It is of East Indian origin, consequently tender. Its position should be in the list of subtropicals. It, like most flowers taken in hand by the florist, has been very much improved, and none but the very best strains should be grown. There are still a number of flimsy trashy varieties sold, of lanky habit and indescribable colour, like the bulk of German ten-week stocks: therefore the first consideration in starting to grow Balsams is to obtain good seed; and when a good strain is secured, seed should be saved from picked plants.
It is no great exaggeration to call many of the better varieties Camellia-flowered. The last two years we had some white flowers that were quite reflexed in the petal, and imbricated, and perfectly double, like a Camellia imbricata, from seed got at a respectable London house; the colours very fine, various shades of red, pink, and almost crimson, white, and mottled, as well as good purples, alongside of which common strains, or indeed no strain at all, would not have been looked at.
The quality of flowers, however, depends much on culture. Under the best management it will be observed that plants which have yielded very fine flowers when in their progressive stages will, when on the wane, produce flowers quite single, though the colours will be still distinct: then is the time to secure seed - to obtain a crop of good plump seed in this climate by planting out a selection of the earliest plants, which have flowered in pots, on a bed of rich soil, in the blaze of the sun in the open air. This is, however, not necessary to seed saving, only it saves labour in watering and house-room; and, moreover, a Balsam in a seedy state is not ornamental indoors. The Balsam should be quickly grown when taken in hand; it requires plenty of sun and air, so that it is not advisable to sow the seed very early in the season. The plants should never be drawn by want of light or room, and not starved for want of pot-room if large plants are wanted. A large Balsam can be grown in a comparatively short time under good conditions. A bright sun and plenty of air are essential to mature the growth as it progresses. We therefore do not advise to sow the seed before the first week in April for the first lot; later sown will even be better.
As the sun increases in power and the plants in size, air may be given with more freedom with the advancing season.
If seed be scarce, we prefer sowing single seeds in small pots, or, if plentiful, more seeds to the pot, selecting one plant and pinching out the rest. When they are well up, the pots are placed in a dung-frame or warm pit near the glass; and at once guard against over much moisture and closeness, as the seedlings will get drawn in one day if forgotten or mismanaged. From the beginning the pots would be better plunged in sawdust or tan, thinly, but more especially as the plants advance in size, when more air is given: a steady temperature of from 75° to 80° at the root is immensely in their favour; the top heat may fluctuate very widely without any harm.
If the seeds have been sown in 3-inch pots, the first shift should be into 6-inch, with one large crock over the hole. They should be shifted when the roots have got well hold of the ball of soil, but not matted. The plants will be by this time short sturdy fellows if they have not been coddled. Some do not mind their being a little long in the stem, as the balls can be kept low in the pots at the time of shifting, and the soil brought up to near the first pair of branches; but we do not advise the practice, because it should not be necessary. When shifted, they must be again plunged, but not in much bottom-heat; the heat of the sun on the plunging material, whether sawdust or tan, will be sufficient in May and onwards.
At this first shift it will be necessary to speak of soil. We prefer turfy loam of a sandy nature, which has been stacked for a few months with layers of dung put up with it; the turf will have absorbed the good qualities of the dung. We chop it up rough on the potting bench, and to it we still add a third of horse-droppings, which have been prepared for the mushroom-house, with the bulk of its good qualities remaining, but sweetened for use: old mushroom dung is poor stuff. If the soil is not sufficiently sandy - that is, if it be of a close texture - a small portion of gritty river-sand should be added, or sharp pit-sand; fine silver-sand is not necessary to such a coarse-rooting plant as the Balsam, although it will do perfectly well. We, however, prefer for coarse-rooted plants a coarser sand. The sand in this instance is not necessary simply to keep the soil open mechanically; sand is necessary, we believe, as a feeder or digester, especially in very rich soils. A plant will sometimes be found not to root in pure dung, but add a portion of sand to the dung, and it roots in it directly.
With the above soil the plants may be potted rather firmly.
Increased attention will now be required to air-giving. The plants must have plenty of room, to allow of a free circulation of air about them, and prevent them shading each other - the lights of the pit tilted half way down the side, not top and bottom, to avoid draughts. They will now make very rapid progress and sturdy growth. Water cautiously after potting for a few days, and always with water the same temperature as the plunging material. A comfortable condition of the root, not actually bottom-heat - as usually implied, that expression is apt to lead astray - but a steady warmth, is one of the most essential points in the culture of tropical and sub-tropical plants; for although the atmosphere may vary in temperature, there is a steady rise or decline in the soil with the season in most climates. Watering with cold water is a serious evil with jjlants in pots, and very soon ruins a Balsam.
The next shift may be into 10-inch or 12-inch pots, if large plants are wanted; 8 or 9 inch pots are large enough for general decorative purposes. If into 10 or 12 inch pots, room should be left for an after top-dressing of dung - sheep's dung we prefer - keeping the plants plunged until they are large enough to be moved into the show-house.
Some pick off the early blooms with the view of retarding the general flowering and strengthening the plants, but we do not think there is much gained; if the plants be quickly and liberally grown, this will not be found necessary. If they have been checked or starved for want of room or water, this picking off the blooms will not make up the difference.
Some also pick and tie out the plants. We have done the same, but the Balsam is a stubborn subject under training; it resists it obstinately. If done at all, it must be done with much caution and coaxing, like tying down the young shoots of the Vine when vigorous. A specimen Balsam should be grown without pinching or tying. We think when a Balsam is manipulated in this fashion, its character is spoiled directly.
When the plants are removed from the plunging material to the show-house, care must be particularly taken not to over-water, especially if in large pots; yet they must not be allowed to flag. Most of the feeding roots will be near the sides of the pot; water should be given round the circumference rather than close to the stem, where it may be allowed to become comparatively dry. They must never be shaded or crowded, but have plenty of air and no draughts. Plants often sicken off when removed to the greenhouse: this is owing to the check of removal from the plunging material in a highly cultivated subject; hence the caution required in watering.
The Balsam can be grown to a huge size, with attention to potting and growing on. We have seen them in 18-inch pots from 3 to 4 feet through every way, but we never grow them that size. We once saw a Balsam, grown by a cottager and exhibited at one of the leading provincial shows, which was the above size, and was the wonder of many. The first referred to were about a dozen in number; they were grown in a lean-to house, an old pine stove. The plants were plunged in the pit in front, under the lower sashes of the house, and the upper sliding sashes were entirely wanting; so that the Balsams enjoyed themselves perfectly: abundance of air, no draughts, comfortable at the roots, and the full blaze of the sun. They were grand plants, were neither tied nor pinched, but stiff and short jointed, the centre stems as thick as a man's wrist.
When the pots are filled with roots after the last shift, and while the plants are still plunged, they may have a little manure-water every time. It is needless to say that the Balsam is a gross feeder, and capable of appropriating large quantities of stimulants under a hot sun; but when removed to the show-house, manure-water must be administered with more caution, and none at all when the weather is dull and wet. A little top-dressing is better, as they will root up to the warm surface. The Squire's Gardener.