VETTERLE & REINELT — HYBRIDIZING GARDENS 
CAPITOLA, CALIFORNIA 
CULTURE OF DELPHINIUM HYBRIDS 
SEED 
Delphiniums can easily be grown from seed which can be sown practically any time of 
the year according to the climatic conditions, equipment available or time of flowering desired. 
Under California conditions for early Spring flowers sow from June to September, Mid¬ 
summer blooms December to January, and for Fall blooms February to April. In regions 
with severe Winters, the early Summer sowing from June to July is recommended so that the 
little plants are well established before the Winter sets in. Otherwise, the most practical time 
to sow is early Spring. Seed can be kept in good condition for several years if kept in air-tight 
containers in a refrigerator. In fact it is practicable even with fresh seed to place it between 
two moist blotting papers and leave it directly under the freezing compartment of the re¬ 
frigerator for at least a week to induce a higher germination. For best results sow in flats in 
a mixture of two-thirds coarse leaf-mold and one-third loam, covering slightly with the same 
mixture and moisten thoroughly. To prevent evaporation, cover the flats with newspaper and 
glass until germination takes place. Immediately after the young plants begin to appear, both 
the glass and the newspaper should be taken off, however, the plants should be kept shaded 
and kept moist constantly. 
GERMINATION 
If the seeds do not germinate 100% and the flats are exposed to strong light immediately 
after the first few plants have appeared the rest may not germinate at all. Artificial heat 
can be used for germination in early Spring and it will give far better results than the natural 
heat in Summer. To get the best results in germination, bottom heat is necessary with a cool 
temperature overhead. This is well supplied under glass in early Spring, however, in Summer 
due to hot weather conditions it is usually the opposite and this is why many people have 
failures even with the very freshest seed. At temperatures of 8 5 degrees Fahrenheit and up the 
germination is often very poor and what germinates stands a very good chance of being simply 
cooked. To prevent this, after the seeds are sown in flats place them on the floor in a cool 
room or shed where they can be kept dark for the first ten days until germination takes place 
then give light and fresh air but keep them well protected against any drying out. We have 
repeatedly checked on seeds which were sown under greenhouse conditions in Summer or the 
cool shed method or a well shaded lath house and the results in each case were from 20 to 
5 0 per cent better under lath house conditions than under the greenhouse conditions. Under 
slow cool germination practically every seed will gradually come up, under quick hot con¬ 
ditions only a few will germinate, the rest remaining dormant in the soil. 
DAMPENING OFF will occur only if flats are kept too wet in the greenhouse without 
proper ventilation. Watering with a weak solution of chlorox, about four to six per cent, we 
have found to be the best cure and preventive. 
TRANSPLANTING 
When second leaves are developed and before plants are too crowded, prick in flats three 
inches apart in a mixture of two-thirds sandy loam and one-third leaf mold. Keep shaded for 
two or three weeks, then gradually give more light and when larger, harden off in full sun¬ 
light before planting out in permanent position about two or three feet apart. 
Open sunny location is necessary for best developement. In shade they will grow too spindly 
with only small flower spikes. If too close to walls, they will Mildew more than in the open. 
The ground should be well prepared for planting. A liberal application of well-rotted cow 
or sheep manure with a sprinkling of bone meal mixed with the soil which should be dug a 
foot deep, will produce fine growth. Heavy wet soils will require a slight addition of lime. 
Good drainage and uniform supply of moisture during the growth is essential. 
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