This section is from the book "The Florists' Manual", by William Scott. Also available from Amazon: The Florist's Manual.
No feature in carnation growing has undergone such a change as the time of getting them from the field to the houses. From end of September twenty-five years ago the lifting time has been moved year by year forward till now early July is the time our best growers, lift their plants from the field, and from what we have observed and from our experience the past two years the first or second week of July is the time. If you could lift them all at once we would say let that be done about July 10, but it necessarily must take a week or two, so begin at the first of July. There are several good reasons why this early planting is the thing, and let us remark that early lifting calls for early propagating and getting them into the field in the early days of May, or, perhaps, in more favored latitudes, the last days of April. This seven or eight weeks in the open ground has given them a robustness; they have laid the foundation for sturdy plants; they have made a good ball of roots, but they are not spread out, and when lifted every particle of root can be preserved. We used to wait for a rain in the old days. With these comparatively small, compact plants there is no need of that, for there are no long roots to lift and the plants relish the change from the often hot, dry field to the moisture of the bench. I have never seen a bench of plants planted in early July wilt to any extent. The plant is in no condition to wilt. The best all round carnations we ever saw, of more than six varieties, were benched from July 5 to July 10. They then will quickly take hold of the new soil, and all the growth they make inside is strong and vigorous and the first flowers you get are perfect. With many growers, particularly those who retail their own flowers, it is a serious loss to throw out their plants before school graduations are over, somewhere along after the middle of June. This allows you to get all there is in your carnations and gives you time to clean out houses, renew soil and in with your new crop.
Within five or six years an entire inside culture has been tried and in some cases with the greatest success. Some varieties may be better adapted for this method. We believe if you should find yourself with an empty house at the first of April or even up to first of May that it would be the very best plan to put your carnations on the bench at once, instead of in the field, but we do not believe it would pay to throw away a bench on May 1 that was yielding, or would yield within a few weeks, a fine cut of flowers. There is no doubt that some varieties, notably Lawson and Enchantress, grown entirely under glass, will yield as many flowers, and magnificent flowers, and what is more continue to bear flowers as long as the plants lifted from the field. If you are after long-stemmed, perfect flowers in early fall, say September and October, then the inside culture is the plan. That we have proved. We think the earlier they can be planted the better the result and that if you want to try this system, but can't get them on the bench till first of June, you had better have put them in the field at the first of May, and for two months they would be doing better than cramped in pots and run the very likely risk of suffering for water. The greatest hindrance to this method with the average florist is that he loses a valuable part of his crop and it is more expensive to carry his young stock over the month of May in pots than planted out. The specialist who supplies the fancy trade of a large city it may pay to throw out his carnations after Easter and on his young plants he may gain largely in early fall with his perfect flowers what he loses in May and June. Yet they lift so perfectly and take hold so quickly in July that two months in the field will be found the better plan and least expensive. No doubt circumstances will induce us to adopt both plans, for they are both good. The great forward strides we have made is in early planting.