4 BULLETIN 797, U. S. DEPARTMENT OF AGRICULTURE. 
than on heavy soils. The character of the bulbs grown on heavy and 
on light soils will vary somewhat, of course, as it will with shallow 
and with deep planting. The indications are that success can be 
secured in bulb production on a friable loam soil, whether it has a 
preponderance of sand in its composition or not. 
TEMPERATURE, SOIL, AND FERTILITY REQUIREMENTS. 
We may gain a valuable lesson as to the requirements and suit- 
ability of these bulbs from the long private experiences of those who 
have flowered them either in pots or in borders in different regions 
and then tried to carry on their propagation. It is the common 
experience that these stocks gradually deteriorate in size in the hands 
of the small grower. This is not always a proof of lack of adapt- 
ability, because it is seldom that the stocks are properly handled. 
They become overgrown with weeds, are left undug too long, or are 
improperly fertilized. 
About 40 miles from the coast in northern California we have a 
record of an apparent intelligent handling of Darwin tulips over a 
period of years. Here, with good fertility and proper handling, the 
bulbs gradually deteriorate in size. Two natural conditions in this 
locality seem to be accountable. The moisture is likely to fail sud- 
denly before the plants complete their growth, and the temperatures 
are likely to run suddenly high at the same time, thus shortening the 
growing period suddenly. Such conditions are evidently not suited 
to commercial bulb production. 
The consensus of experience in the vicinity of the District of 
Columbia probably would be very similar to that in the interior 
region of northern California — the bulbs gradually deteriorate in 
size. In this region, however, the average soil is naturally poor, 
which, coupled with imperfect growing of small lots, is responsible 
for much of the failure. There has been recently ample proof that 
all of the robust varieties of both the nacissus and the tulip can 
be successfully produced in good quality even here. It is not to be 
considered, however, that the conditions are by any means ideal. 
The main adverse condition, aside from natural lack of soil fer- 
tility, is the high temperatures, which are normal for May and June 
and occasionally occur even in April. There is also an uncertainty 
regarding moisture supply before the end of the growing season. 
Suitable temperature, moisture, and soil conditions obtain in both 
our Atlantic and Pacific coast regions. In the interior of the eastern 
United States, as far west as Illinois and Michigan at least, condi- 
tions are favorable enough for success. The temperature is not as 
favorable as in the cooler coastal climate, but, in our opinion, where 
friable well-drained soils occur the conditions are generally as satis- 
