Here is what I could find:

CACTUS GROWING TIPS
Most cacti come from dry areas of the Americas. There are however some that live in the tropical jungles! And many of the succulents come from reasonably wet areas of the African continent.
The natural growth cycle of many of the American cacti take advantage of the occasional flooding of the desert. These floods will rip through a canyon sweeping up all in its wake. The cacti swept up break into many pieces and are deposited along with other floatsome spread along miles of ravines and arroyos. The cactus pieces will be half buried in a minerally rich, loose mix of rock chips, sand and organic debris. The broken pieces will quickly grow roots from the areolas (the mole-like places where the spines grow from), these roots anchor the plant as it bends up to reach for the sun.
These conditions are what the outdoor cactus grower must strive to reproduce. Well draining soil is definately an advantage to reduce chances of rot. If your soil is heavy you can construct raised beds with rings of stones filled with a gravely mix. Mineral rich soil is helpful in growing healthy plants, the desert soils are often mineral rich. Adding compost will add minerals and help beneficial bacteria release the minerals naturally present in most soils. In fact compost is helpful if not essential for all soils, it will help open the structure on tightly bound clay soils, and help reduce excessive drainage on too gravely mixes.
A sunny spot is best for most cacti, but all will live with light shading or partial shade. A hillside with southern exposure is ideal as the excessive water will drain away quickly, and the cold air in winter will drain to lower locations also, reducing freezing damage.
Freezing damage can also be lessened by reducing water in fall to lower the plants' moisture content. Cease fertilizing with nitrogen sources in mid summer to eliminate new growth that might be more succulent in winter. Fertilizing with kelp extracts in summer and through the winter is reputed to reduce frost damage by imparting an 'anti-freeze' quality to the plants.
Your Opuntia cuttings will have no roots, this helps reduce rots and the plant having to chance having broken roots when planted. Rest assured the leaves will put out roots in a short time after planting. The Opuntia pads should be buried about one half to two third of their length in the soil. Most growers prefer the Opuntia have one of the thin edges facing south to reduce the sun exposure in the heat of the mid-day. Yet the wide flat parts of the pads are showing to the sun in the lesser heat of the sunrise and sunset. One will notice that the orientation of the mature leaves is generally this direction.
Cacti have a waxy coating called a 'glaucus bloom' that helps seal the plant moisture off from the external elements. This bloom can be removed with some pesticides, even organic ones! So be careful in what you spray on the plant, the removal of the bloom will not necessarily kill it, but will affect the appearance of the plant. The bloom does not grow back again, but new growth of the plant will have the necessary waxy coating.

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