Rose Annual (1947) 125-127
Germinating Rose Seeds
By FORREST L. HIEATT
San Diego, California
THERE is a lot to be learned about germinating rose seeds. Why do the seeds of some varieties germinate in a few weeks while those of others lie dormant for several years before showing signs of life? Why do some seeds of a given cross germinate quickly, while others from the same hip require several years? These are some of the many questions whose answers will be most welcome. If we all apply ourselves to advancing the knowledge of germination, we shall solve many of the perplexities of rose seed germination. I get fifty per cent germination from the seeds of Arles within sixty days, while the remainder of the lot germinate intermittently over a period of two or more years. The seeds of many other varieties make no pretense of germinating until after two years. Mr. Shepherd may be losing some valuable results by discarding his seeds after twenty months. (ARA, 1945, p. 121.)
After reading the article by Miss Barton on 'Germinating Hybrid Rose Seeds' (ARA, 1937, p. 33), I followed the suggested proceedings with my 1938 seeds with only partial success. Then I decided to make a comparative test with my 1939 crop. From each hip with a multiple number of seeds, I put one-half in two-and-a-quarter-inch pots and put them in my germinating shed as usual. The other half was placed in small boxes made by cutting a one-inch square out of each corner of a three-inch square of 28-inch gauge copper and bending the projections at right angles to give a box one inch square and one inch deep.
Comparing the results: The unrefrigerated seeds began to germinate in two to three weeks and germination was 200 per cent better than that of the refrigerated seeds. From this I concluded that the refrigeration method was of little value and in fact, may have delayed germination.
After keeping both lots for five years, I discarded the unrefrigerated seeds. Not needing the copper boxes, I set the pans outside the shed. This was in February, 1945. In the latter part of March after several days of gentle rain, I noticed to my surprise a great number of seeds in the pans had germinated. I returned them to the shed where 160 seeds germinated in 1945, and 161 in 1946. The last seed to germinate from this lot was on November 4, 1946, more than seven years after the hip was harvested. There was no germination of the refrigerated seeds in 1943 and 1944. These late germinating seeds were all from the lot that had been kept in refrigeration at 41 degrees which was supposed to hasten germination. Some of the unrefrigerated seeds, if kept, might also have germinated in 1945 and 1946, but of course we have no way of knowing.
I agree with Mr. Coddington that cold storage has no particular advantage. (ARA, 1942, p.. 68.)
For the sake of better and more permanent records and accuracy, my hybridizing data is recorded at the time of pollination in a year-book which I carry in my hybridizing kit along with pollen jars, etc. In this book, opposite consecutive numbers, each cross is recorded showing parentage and any other useful information such as weather conditions, humidity and the like. The cross is identified by tying a price tag with a number corresponding to the book record on the pedicel of the prospective seed parent..
Since not all crosses are successful, these numbers are temporary and give way to permanent numbers which are given the successful crosses in the order in which the hips are harvested. This provides a record on the early maturing hips without having to refer to notes. The numbered hips are gathered as soon as they are ripe and are entered in a germination record book under the permanent numbers. These they carry through the germination period and on through the life of the plants until, or when, they are given names.
The hips are opened at once and the seeds given a Semesan bath and put in two-and-a-quarter-inch pots. They are covered one-half inch deep with granulated peat moss after a record is made of the number and kind of seed. The floating seeds are planted along with the sinking ones, for I have had instances of floating seeds germinating. The pots carry the identifying numbers written on each pot with a weather-proof pencil. I have found the Eberhard Faber pencil the most satisfactory. The pots are then plunged in peat moss in a rodent-proof germinating shed. This is constructed with a concrete floor, a tight roof and tight walls up to three feet. Above three feet, the walls are of one-quarter-inch mesh galvanized hardware cloth to keep out the birds which just revel in pulling the seedlings out as soon as the cotyledons appear. The pots are kept moist and are examined daily. The newly germinated seedlings are potted in two-and-a-quarter-inch pots and are kept in the shed until the first true leaves appear. They are then transferred to an unheated glass house where the humidity can more or less be controlled. They are grown on in this glass house until large enough to be planted in the field, which, in this climate, can be done throughout the year. The potting soil consists of 2 parts of sandy loam and one part of peat moss. Incorporated in this mixture is one-quarter of one per cent of agricultural sulphur to prevent damping off.
I use peat moss in germinating because it can be kept moist without becoming water-logged, a difficulty encountered when using soil which contributes to damping off. Sterilized clay pots are more sanitary than flats can possibly be. They prevent the possibility of seeds getting mixed or identity lost as can easily occur where flats are used. By using a uniform size of pot they can be placed orderly in regular rows in the shed. One two-and-one-half-inch pot will take care of the seeds from most hips. Where more than 20 or 25 seeds occur, a second pot can be used. I find in most cases when the cotyledons first appear, the tiny seedling already has a root an inch or so long. Potting at this time is safer than waiting for the permanent leaves to appear.
I have had the best germinations this year that I have ever had at this season. The 1946 seeds were planted the first week in November and I had 50 germinate before December 1. This was 25% of all germinations for November. In December, I had 250 germinations, 125 of which were 1946 seeds.