As the sun in England is not nearly so powerful as in the hot plains of
Central America and the Southern States of North America, where Cactuses
are found in greatest abundance, it will be evident that, if flowers are
to be produced, we must see that our plants have a sufficiency of water
in early summer, and little or none during the autumn and winter, whilst
the whole year round they should be exposed to all the sunlight
possible, the temperature, of course, varying with the requirements of
the species, whether it is a native of tropical or of temperate regions.
It is important that the cultivator should understand that if water is
liberally supplied all through the summer, the plants cannot obtain the
rest which is necessary to their ripening and producing flowers, as
dryness at the root alone is not sufficient to provide this, but must be
accompanied by exposure to bright sunlight, which is not possible in
England during winter, so that the ripening process must begin before
the summer is over.

It is possible to preserve most Cactuses alive by keeping them
constantly growing; but, with very few exceptions, such treatment
prevents the plants from flowering. The following is what is practised
in the gardens where Cactuses are successfully cultivated. For the
genera Cereus, Echinopsis, Echinocactus, Mamillaria, Opuntia, and
Melocactus, a moist tropical house is provided, and in April the plants
are freely watered at the root, and syringed overhead both morning and
afternoon on all bright days. This treatment is continued till the end
of July, when syringing is suspended, and the water supplied to the
roots gradually reduced. By the end of August, the plants are placed in
a large light frame with a south aspect, except the tall-growing kinds,
which are too bulky to remove. In this frame the plants are kept till
the summer is over, and are watered only about once a week should the
sun be very powerful. The lights are removed on all bright sunny days,