This section is from the book "The Gardener V2", 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.
One would fancy that of such old-fashioned common flowers as the French and African Marigolds there would be very little to say. Nor is there much. Only, as the scope of 'The Gardener' is not restricted with regard to the subjects discussed, and as I know that a good strain of these well grown commands a good deal of attention from the flower-loving portion of the community who visit gardens, I have therefore thought that a note on their culture would not be wholly out of place.
And first as to raising the plants: I sow about the middle of April in a cold frame in which a bed of soil is prepared, and the seeds are thrown broadcast over the surface thereof, and merely pressed firmly in without further covering of soil. The sashes are kept closed, and covered with mats until the seeds have germinated. The mats are made use of thus to secure partial darkness to the seeds, and also to preserve a uniform amount of moisture in the soil without having to apply water. When the young seedlings appear both light and air are freely admitted, and when weather permits the sashes are entirely dispensed with. The seed is sown very thinly, and the soil is of a light and rich nature; so that, while it is not necessary to prick out the seedlings before transplanting them into their "blooming" quarters, the nature of the soil allows for this being done without destroying the roots of the plants, and consequently without their receiving a check from the operation. When slugs abound, larger plants than these thus grown might be found to do better, as slugs have a great liking to young Marigolds. Sowing a little earlier and keeping the plants warmer would be necessary in such cases, but otherwise small plants grown without a check are most satisfactory.
Growers for exhibition commonly plant in beds. I find them do equally well either in lines amongst other plants or planted singly in mixed borders. Whichever plan is chosen, a rich well-cultivated soil is necessary to have them fine. Each plant, if well grown and space allowed, will make a bush three or four feet through towards the end of the season. It is well to remember that allowing them plenty of space for growth secures quite as many flowers as if, say, double the number were grown; whilst those plants having the most room for head-growth produce the finest blooms. If the weather is dry when the plants are put out, one good watering is given, some dry soil being thereafter drawn over the surface as a check to evaporation. Small plants may also have their roots drawn through a mixture of water and soil - mud, in fact. This is found very beneficial in extra hot weather. Except when first planted out, our plants are never watered. Where autumn winds are destructive, it will be necessary to take the precaution of securing the plants by one or more stakes, otherwise no supports are required. The only other points to be attended to are the removal of the flowers when "over," and securing a sufficient number of the best flowers for seed.
African Marigolds are further benefited by having the flower-buds thinned out. The flowers cut for seed should be hung in small bundles in a dry warm room to ripen: this is a somewhat important matter, as good well-ripened seed is not always to be got. These past few years seed has been very poor in germinating quality. In selecting French Marigolds for exhibition, blooms with distinct and even markings should only be cut; depth of petals ought also to be considered, as well as the width of the flower. Any undeveloped florets in the centre of the flower should be removed, as also those grown out of shape. African Marigolds do not form such symmetrical blooms in cold weather as in warm: warm positions should therefore be given these. Also in preparing blooms for showing, their symmetry is improved by removing florets out of harmony with the rest. The colours of these cannot be too pure - the nearer to a dark orange or a clear lemon the better. From a mere utilitarian point of view I find Marigolds very useful. The French is used, in the case of self flowers, which are, some of them, very rich and dark, others pure yellow, for mixing in vases. The African is much used for church decoration in autumn; these are also very sweet-scented, a fact not very generally known.
I also grow a very good selection of the old double-pot Marigold. Being quite hardy it receives no other culture than a good soil.
R P. B.