We can remember pots of lily of the valley being grown in our greenhouses in March and April many years ago. These pots (a 5-inch or 6-inch) contained a solid mass of roots and were not disturbed or shifted for several years. After flowering they were stood outside and kept watered till fall, when they were plunged in coal ashes and a few inches of the same material thrown over them. This was growing them in a natural way, and a very great addition they were to the attractiveness of the conservatory. As pot plants they are of little consideration. Within twenty-five years the flower must now be supplied the year around.
When first lily of the valley was produced in the summer and fall months it commanded a most lucrative price, but nowadays at the close margin at which it is sold you must be successful or you had far better not attempt it; rather leave the growing to the specialist and buy your flowers from the grower or commission man.
A few years ago in the columns of one of the trade papers appeared several articles from the pen of Mr. E. Simpson, who can not only write plainly, and explicitly convey his knowledge to us, but has been one of the largest and most successful growers of this dainty little flower, and though not copying him verbatim, I acknowledge to him many of the important details on growing now given in this article, and particularly the care of the pips in cold storage, for it must be remembered that while the winter is the natural cold storage for the pips that give us the flowers from the middle of January to possibly the end of May, the other seven or eight months we must depend on those whose growth has been arrested by cold storage.
I never did believe that to put the original cases into cold storage and expect them to come out in seven or eight months and give good results was at all the reasonable or proper plan. When first received, which is usually in November, unpack at once. Large growers place them in trenches in coldframes and between each row of trenches put some sandy soil or finely sifted coal ashes, and over the tops of the pips two inches of the same material. Small growers will find boxes holding conveniently the quantity they want to force weekly or biweekly more convenient than the first plan, because you can easily bring in the box containing just the quantity you want. When putting them outside the smallest and weakest pips should be put by themselves and labeled and reserved for the latest spring forcing, but with those that are to go into cold storage it is just the reverse, and those which are to be retarded longest should be the strongest.
Sometimes we find the roots very dry. L prefer to dip the roots for a few moments in a tub of water before putting outside. Let a frost come, a good, hard one, so that the covering is frozen, and no harm if the roots are, then put a foot of hay or excelsior over them and cover with shutters to. keep off rain. It is not well for the roots to be too wet. Glass sash would keep off the rain, but it would also raise the temperature on bright days during a thaw, and that is just what you don't want. These conditions will do for all the pips that you force during winter and up to the time that we get the flowers outside. But long before this you must have removed to the cold storage the roots that are wanted for summer and autumn.
The time to put them in cold storage may vary by a month because the weather varies. They must be absolutely dormant when removed to the cold storage, and that must be closely watched. We have tried repeatedly to store away a few thousand in our local cold-storage warehouses, and if we could be always successful with them it would be a great convenience and cheaper than building one of your own. But it is very uncertain work and we have often blamed ourselves when perhaps it was the cold-storage management that was at fault.
Mr. Simpson at some length gives instructions how to build a cold-storage house, but were I to repeat it I am sure you could not build one by it without visiting some one who has one and seeing for yourself " how to do it." The most comforting part of it is that he says a cold-storage house that will hold 400,-000 valley roots can be built for $600. The interest on that sum seems very trifling when the success of even a quarter of the above number is grown. Whether you have your own cold storage or hire it, the conditions which you should try to preserve are these:
Get boxes of convenient size, six or seven inches deep, line them with moist sphagnum moss and between the bunches of roots put moist sand, not saturated, and cover pips with an inch or two of sphagnum. To occupy little space you will have to put slats or boards on top of each box, so that they can be piled up one above the other. In renting space in cold storage this would be a great consideration. When first put in give them 10 degrees of frost and in a few days let the temperature go up to 28 or 29 degrees and remain at that.
In large cold-storage houses they have rooms at all temperatures and will ask you what degree you want, so the same plan can be carried out by moving the boxes. If when removing the roots from the frame to cold storage they appear dry, give the whole box a watering before putting it away, but it is not well for the sand to be too wet or the roots may rot. Those small growers who hire the local cold storage for their arrested lilies may as well put them in suitable boxes when first receiving them in the fall; then with the addition of some moist sphagnum over the pips they can be easily removed at short notice to their cold surroundings.