This section is from the book "The Florists' Manual", by William Scott. Also available from Amazon: The Florist's Manual.
When planting out for your own stock give the plants plenty of room to grow and do not crowd or the growths will be soft and unsuitable for cuttings. Unless the season is very dry geraniums seldom want water, and if you must water give them a thorough soaking and then hoe before the ground bakes. That is pretty good advice to apply to a whole lot of things. Keep all flowers picked off as soon as they are fully developed; it will encourage the plants to grow.
About September 1 take off your first batch of cuttings and pot firmly in 2 1/4-inch pots. A coldframe will do for the cuttings, but an ordinary bench is just as good and less liable to neglect. They should be shaded during the hottest hours of the day only, and that can be done with newspapers which is better than any fixed shading because on dull days a shading would be injurious.
Potting firmly with a good, sifted loam is an important point. Don't thumb the top of the soil, but get your finger and thumb down by the side of the cutting like a wedge, and make the soil around the base of the cutting firm. The watering will take care of the surface without your wasting any time with your thumbs.
They want a good, thorough watering when first potted; after that only when they are decidedly on the dry side. There are more geraniums go off black and rotten through the heat and moisture than there are from dryness. In a month most of them will be rooted, and when they commence to make new leaves they should be stood over, dry leaves rubbed off and the surface of the soil stirred. From now on you will have to treat them barbarously to keep them from thriving.
Geranium Little Pink.
Bench of Bruant Geraniums.
Why you should wait till September 1, or about that time, before propagating is because earlier propagation in a hot spell in August is not safe. I have seen seventy-five per cent of fine cuttings turn black in a few days when we had very warm weather. Any kind that you were very short of can be propagated earlier, but it would be safer to put them in the sand.
By taking off all the leading shoots thus early you will usually by middle of October get another good lot of cuttings, which root still more certainly. If you don't have time for another batch these plants are in excellent shape to lift and pot and propagate during winter.
Florists that grow a variety of plants had better do their operations by a system, and our system is to get all our geraniums propagated in the fall without need of lifting old plants. A light house should be given to geraniums; it cannot be too light and dry and airy. A night temperature of 45 degrees will bring them along fast enough.
After our holiday trade there is room to spread out, and then our geraniums get a shift into a 3-inch pot. It is not much of a shift, but it makes a great difference to the plants. About February 1 they have made good roots in the new pots and then we stand them over, taking off all the tops that will make a cutting, and those that are not long enough we just pinch out the center. The cuttings from the tops of these 3-inch plants will root most easily at this time of year; potted in 2-inch you will not lose one in a thousand.
 
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