Much has been written regarding the difficulties encountered in growing Delphiniums from seed. To my way of thinking, these difficulties have been greatly over-emphasized with the result that gardeners either lave been reluctant to try sowing Delphinium seeds, thus depriving themselves of a great deal of pleasure, or they have overdone the operation, using too many artificial safety devices.
A number of years ago it was found that fresh Delphinium seeds, hermetically sealed in bottles and kept in a cool place, would retain viability for many months. I have had excellent germination from seed stored variously either with maximum care or downright carelessness. I have sown the seed in nine different months of the year and find that, given half a chance, Nature does its work, if we take reasonable care in trying to duplicate conditions that exist when natural germination takes place.
After all, Aquilegia and Petunia seeds to me present greater difficulties than Delphiniums. On the other hand, all three self-sow in the garden and come up in myriad’s of healthy little plantlets. And we all know that Petunia and Aquilegia seed are hardly larger than coarse ground pepper.
From experience, therefore, I have concluded that I can, with a minimum amount of effort and a maximum result, be almost assured of success by merely following Nature’s rules.
When to plant
Your first crop of Delphinium blooms will, in this climate(Mass. USA), go to seed in July. The seed drops on the ground, the wind covers it lightly with dust, and moisture and sunshine do the rest. So then, plant your Delphinium seeds some time before August 10 if possible.
How to plant
As we have seen, Nature does not bury the seeds at all, it barely covers them. So press your seed into the soil and then sift over them lightly some sandy soil or even just fine sand.
Nothing will grow without moisture. Therefore, it is essential that your seedbed not be permitted to dry out but be kept consistently moist but not muddy. This may be best accomplished by watering the soil well before planting.
To preserve moisture and protect from drying out by sun and wind, the outdoor planting is covered with a frame of standard cold frame size, 3 feet by 6 feet, made of furring strips on which is tacked unbleached muslin. This is kept on until seeds have germinated. During rainstorms, the glass sash is placed right over the muslin (sash) frame to prevent dripping to wash out the seeds. Plastic will work just as well.
The ordinary summer temperature, existing at the time of the year when Nature plants its seeds, will, of course, be ideal when you plant your seeds by hand. The more even the temperature can be kept, slightly above 70°, the better.
When seedlings show
Just as soon as the seedlings break through the ground, the covering should be removed or spindly growth will result. When the Delphinium plants drop their seeds at their own feet, the seedlings are naturally partially shaded by the old plant. That’s the condition you will wish to duplicate, and this can be done with slatted frames made of furring strips on which laths are tacked one half inch apart.
When the true leaves begin to develop, transplant the seedlings into a well prepared bed in a sunny position in the garden which, however, is more satisfactory if naturally protected from high winds. As the seedlings develop, a very weak solution of chemical fertilizer will help develop strong plants. The location should be one, which will not retain puddles of water, which may freeze solid in winter. My experience has been that these seedlings thus planted in the open will winter-over, even though extremely cold, if, when the ground begins to freeze, they are covered merely with a quarter of an inch of coarse sand. The following spring, strong plants should develop and can then be planted into their permanent positions in the garden.
For one who may use only one package of seeds, I would plant in seed pans. I recommend a mixture of one-third good garden soil; one-third sand and one-third finely ground peat moss or leaf mold. Mix together thoroughly and sift out. Then cover the bottom of the seed pan with pieces of broken flower pots, fill the pan with the soil mixture and stand the seed pan in water to about one-half the depth of the pan for about a half hour.
Much has been said about damping off of seedlings. If clean pots, clean soil and a little care is used regarding moisture, the precaution to sprinkle the soil after it is in the pot with a fungicide solution should suffice to eliminate this trouble. Therefore, prior to sowing seeds, mix the solution in a fine spray watering pot and sprinkle the seed pans from the top. I place a piece of newspaper over the seed pans all night and then permit them to air for twenty-four hours before planting the seeds. Planting is done as soon as excess water has drained from the soil in the pan.
Seeds are sprinkled evenly on top of this soil and pressed in. I then sprinkle a little of the same soil mixture or just plain sand lightly over the seeds. Do not water again. Of course, the covering soil should have had the fungicide treatment also. I then place the seed pan where it will not dry out and where a constant temperature may be maintained. Cover the seed pan with a piece of glass until seeds have germinated, which they should do within ten days. If, through any chance, the seed pan shows signs of drying out, stand it in water again for a short time to give it an opportunity to soak up moisture.
When I plant large amounts of named varieties, I select a spot in the garden protected from the wind, prepare the soil well, mixing in the top two or three inches sand and sifted peat moss. I place over this plot a wooden frame made of 6-inch boards and of the proper size to take a standard three by six coldframe sash. Before planting I water well, the final watering being with the fungicide solution (use as directed on the package) putting on the sash over night so that the fumes can well disinfect the soil. Then after airing, the seeds are planted in rows, carefully labeled and covered lightly, following the same procedure as indicated above for planting in seed loans. The frames are covered with unbleached muslin or burlap shades during germination and with glass sash in case of storms.
If the seedlings are not too thick in an open bed, from one-half to one inch apart, I have not found it necessary to transplant them in the fall, but have left them in the seed bed during the winter and haven’t moved them until ready for transplanting into the permanent bed the following spring.
During the fall, it is wise to dust the seedlings, maybe two or three times before winter sets in, with Bordeaux mixture.
There’s only one reason why I may favor growing Delphiniums from seed sown in the greenhouse in February, and that is to satisfy my own curiosity. Seeds planted that early can be transplanted into the garden in June, and if you are working with a new variety which you have never before seen, then you have an excellent chance of getting some seedling blossoms before snow flies.
It seems to me that it is good business for Delphinium enthusiasts to develop a simple and effective method of growing plants from seeds. In the first place our able hybridists are continually producing new and interesting strains which most of us wish to try. Further, like practically all perennials, Delphinium clamps gradually develop more numerous spikes and smaller flowers. I have found that a plant that goes three to four years is then in dire need of being broken up, cuttings must be taken from the old clumps. This is not too easy an operation to perform with success. I find it much easier to carry on my rejuvenating campaign by growing new seedlings. Then, too, Delphiniums are not immune to disease. In fact, there are blights, which are very destructive and usually fatal. However, replacement is not difficult if seedling plants are continually coming along. Then, again, some of the more highly developed hybrids (in my experience the “whites”) are short lived and very often die out over winter. So there again is a good reason for growing from seed.
Therefore, if you plan to sow some Delphinium seeds each summer, just as you plant peas and spinach every spring, you will keep your Delphinium garden at its height and at the same time know about and enjoy the new introductions.
By L. BRUGGEMANN